Tuesday, August 30, 2011
Sunday, August 28, 2011
Friday, August 26, 2011
Monday, August 22, 2011
15 Animals You Won’t Believe Aren't Photoshopped
Cracked.com has a very fun article on some neat-looking animals like Ankole-Watusi Cattle which is captioned: "That's the smile of a boy who will never, ever be fucked with again." Go here to see the full list!
New drug cures H1N1 and 14 other virus types via very clever system
from National Geographic News
New Drug Cures Multiple Viruses in Human Cells
Single treatment can kill 15 virus types in 11 mammals, study shows.
by Christine Dell'Amore
There's no cure for the common cold—yet.
A new drug can scout out and kill numerous types of viruses infecting human and animal cells, researchers have announced. It's the first time a single drug has been shown to work against a range of viruses, from those that cause seasonal sniffles to more fatal diseases.
"Several decades ago the discovery and production of antibiotics revolutionized the way bacterial infections were treated," said study co-author Todd Rider, a senior staff scientist at the Massachusetts Institute of Technology's Lincoln Laboratory and Division of Comparative Medicine.
"We hope that this will similarly revolutionize the way viral infections are treated. That covers everything from cold and flu viruses to more serious clinical pathogens like HIV and hepatitis viruses and ultimately even more deadly viruses like Ebola and smallpox."
Alien-Like Viruses Tough to Beat
Though there are plenty of drugs to treat bacterial infections, there are few that can battle viruses. The antiviral drugs that have been developed are highly specific, with each drug targeting just one strain of a virus, which can easily mutate and become resistant to the medication.
So Rider and colleagues took a different approach—tailoring their new drug to work with the body's built-in defense mechanism.
Viruses operate "sort of like the aliens in the Alien movies," Rider said. "They'll enter a cell, replicate inside the cell, and ultimately burst out of the cell," killing it.
While taking over cells, viruses produce what's called long double-stranded RNA, a complex acid that controls the virus's chemical activities and is not produced in healthy human cells, according to the study, published July 27 in the journal PLoS ONE.
Human bodies do have natural defenses against viruses: They produce proteins that latch onto double-stranded RNA and prevent the virus from replicating itself. But many viruses have evolved ways to shut down these proteins.
New Drug Packs Double Whammy
Rider and his team developed a drug that combines the natural-defense protein with another protein that triggers a cell's suicide switch. All human cells have these suicide switches, which are usually activated when cells start to become cancerous, Rider said.
The result is like the mythological centaur, said Marie Pizzorno, a molecular virologist at Pennsylvania's Bucknell University.
"The horse is one piece of a protein that normally we make and that can recognize the [long double-stranded DNA] made by the virus, and the man is something that triggers the cell-death pathway," she said.
The new drug, called DRACO, works by searching for cells in the body that contain long double-stranded RNA—a surefire sign of a virus. If the drug finds a viral infection, it tells the cell to self-destruct.
Since our body doesn't use these proteins together naturally, combining them in drug form may outsmart even the most adaptable of viruses, added Pizzorno, who was not involved in the new study.
"Viruses have figured out how to handle our normal defenses, [but] by activating these two pathways with one protein, they've hopefully prevented the viruses from getting around it."
If the drug does not find double-stranded RNA in the body, it eventually flushes out with no side effects, study leader Rider added. (See a human-body interactive.)
Common-Cold Drug Still a Decade Away
So far, the drug has proven to be effective and nontoxic in killing 15 types of virus—including the ones that cause dengue hemorrhagic fever and H1N1 influenza, or swine flu—in 11 types of mammalian cells, including human.
The drug also cured 100 percent of mice injected with a lethal dose of H1N1, and there are ongoing trials in mice with other viruses.
The next step will be to see if the drug can kill viruses in bigger animals, such as rabbits, guinea pigs, and ultimately monkeys, Rider said.
Then, if the drug is still safe and effective, the U.S. Food and Drug Administration may approve human clinical trials, Rider said. Still, it will be "at least a decade before you can buy this at the drugstore."
Even with all these steps yet to go, the new drug has promise, Bucknell's Pizzorno added.
"It's a really innovative way to consider doing an antiviral," she said. "I don't think anyone has ever thought of this before."
Animal cognition: Chimps fake laugh, sheep know taxonomy and pigeons better at stats then us
(thanks to Damien C for the link!)
By ALEXANDRA HOROWITZ and AMMON SHEA
Alexandra Horowitz is the author of “Inside of a Dog: What Dogs See, Smell and Know.” Ammon Shea is the author of “The Phone Book: The Curious History of the Book That Everyone Uses But No One Reads.”
HUMANS have long been fascinated with animal intelligence. Scientific studies have asked if animals use language or tools; have culture; can imitate, cooperate, empathize or deceive.
Inevitably, the results of these studies invite comparison with our own cognitive faculties. In such comparisons, humans nearly always come out on top. An impartial observer might suggest that the deck is stacked. After all, we are the ones running these tests.
But if we look at some of the subtler aspects of animal behavior, the beasts begin to offer surprisingly stiff competition. A few recent research papers describe animal competence at social and cognitive tasks that humans often struggle with — mastering conversational etiquette, understanding botanical classification, competing on game shows and figuring out how to get a drink when you’re thirsty and the only glass of water is glued to the table and your hands are tied behind your back.
“Aping Expressions? Chimpanzees Produce Distinct Laugh Types When Responding to Laughter of Others,” in the journal Emotion (2011).
You’re at a dinner party. Your hostess regales you with a long, meandering tale of her recent back surgery. It ends with attempted humor: she laughs and glances at you. You laugh in response, trying to convey an appreciation for her humor that you don’t actually feel. Congratulations: you are now at the level of social politeness of chimpanzees.
In this study, the laughs of 59 chimps (yes, they do laugh) were recorded and the sounds analyzed. The researchers discovered that when one chimp laughed others sometimes engaged in “laugh replications” that lacked the full acoustic structure of spontaneous laughter. In other words, they were fake-laughing.
This happened more often in more newly formed colonies, where, perhaps, the individuals were less familiar with one another. With your spouse of 25 years, you can simply stare at him stony-faced when he tells you his favorite “funny” story yet again.
“Do sheep (Ovis aries) categorize plant species according to botanical family?” in Animal Cognition (2011).
Type “Is the tom...” into Google, and the search engine, presuming that you are beset with the same burning question that has plagued so many, offers to finish your query for you: “Is the tomato a fruit or a vegetable?” Given that we humans are still puzzled by the botanical status of one of our most common vegetables, er, fruits, the performance of the 12 lambs described in this study is humbling.
After learning that eating sainfoin, but not fescue, was followed by a stomachache, the lambs knew to pick cocksfoot over alfalfa when given the choice in the future. Have no idea what this means? In non-lamb terms, if a pasture legume caused indigestion (thanks to lithium chloride added by the researchers) but a grass found in pastures did not, the lambs, when facing a later choice between a different legume and a different grass, opted for the grass over the legume. In other words, the lambs demonstrated an ability to form a generalization about the relative digestibility of families of plants. (Lest sheep let these findings go to their heads, note that recent research found that some plants communicate with each other to raise defenses against herbivores.)
“Are Birds Smarter Than Mathematicians? Pigeons (Columba livia) Perform Optimally on a Version of the Monty Hall Dilemma,” in the Journal of Comparative Psychology (2010).
The old game show “Let’s Make a Deal” inspired a famous probability puzzle. A contestant has three doors to choose from: one hides a spectacular prize; the other two each hide something considered undesirable, like a goat. Once the contestant makes a choice, the host, Monty Hall, reveals a goat behind one of the unchosen doors, and offers the contestant the chance to switch his choice to the third door.
On the show, few people switched. But famously, probability shows that it is much better to switch. We humans are reluctant to accept this: in laboratory studies, subjects switch only a third of the time. We perform only slightly better if we get a chance to play the game dozens of times or if the probability is explained to us beforehand.
But pigeons that were offered a version of Monty Hall’s choice aced the test. The experiment involved pecking keys and winning “mixed grain,” instead of selecting doors hiding unknown prizes. After training in the game, the pigeons switched 96 percent of the time. The lesson? Take a pigeon with you if you’re going to be on this game show (now back on television).
“Rooks Use Stones to Raise the Water Level to Reach a Floating Worm,” in Current Biology (2009).
One of Aesop’s fables tells the tale of a crow who quenches his thirst by filling a nearly empty pitcher with stones until the water level rises high enough to drink. Displacement is an insightful solution — could a bird really come up with it? After all, one can easily imagine humans failing to do so (say, reality-show contestants who, faced with an immobile glass and a “no hands” rule, contort themselves futilely).
In this study, four rooks (a type of bird) faced an Aesopian task: confronted with a vial partly filled with water and holding a floating worm, could they extract this bounty?
Easy. After considering the problem, they collected and dropped into the tube just enough stones to bring the worm within snatching distance. Look for this challenge to be included in the next season of “Fear Factor.”
There is no need to be either frightened or overly excited by these findings. The animals won’t be taking over anytime soon, and there is very little chance you can train your parrot to help your child get into the right kindergarten (even animal cognition has its limits). And there is still one notable area of behavior in which animals have shown no sign of matching us: they appear to be not at all interested in running experiments testing our cognition.
Smart animals.
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References
Davila-Ross M, Allcock B, Thomas C, Bard KA (2011) Aping Expressions? Chimpanzees Produce Distinct Laugh Types When Responding to Laughter of Others. Emotion DOI: 10.1037/a0022594
Abstract
Humans have the ability to replicate the emotional expressions of others even when they undergo different emotions. Such distinct responses of expressions, especially positive expressions, play a central role in everyday social communication of humans and may give the responding individuals important advantages in cooperation and communication. The present work examined laughter in chimpanzees to test whether nonhuman primates also use their expressions in such distinct ways. The approach was first to examine the form and occurrence of laugh replications (laughter after the laughter of others) and spontaneous laughter of chimpanzees during social play and then to test whether their laugh replications represented laugh-elicited laugh responses (laughter triggered by the laughter of others) by using a quantitative method designed to measure responses in natural social settings. The results of this study indicated that chimpanzees produce laugh-elicited laughter that is distinct in form and occurrence from their spontaneous laughter. These findings provide the first empirical evidence that nonhuman primates have the ability to replicate the expressions of others by producing expressions that differ in their underlying emotions and social implications. The data further showed that the laugh-elicited laugh responses of the subjects were closely linked to play maintenance, suggesting that chimpanzees might gain important cooperative and communicative advantages by responding with laughter to the laughter of their social partners. Notably, some chimpanzee groups of this study responded more with laughter than others, an outcome that provides empirical support of a socialization of expressions in great apes similar to that of humans.
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Ginane C, Dumont B (2011) Do sheep (Ovis aries) categorize plant species according to botanical family? ANIMAL COGNITION 14(3): 369-376, DOI: 10.1007/s10071-010-0371-4
Abstract
The ability of grazing herbivores to assign food types to categories by relying on certain relevant criteria could considerably reduce cognitive demand and increase their foraging efficiency when selecting among many different plant items. Grasses and legumes differ functionally in vegetation communities as well as in nutritive value. We aimed to determine whether sheep can generalize an aversion they learnt for a grass or a legume species to another species of the same functional type and consequently whether botanical family is a potential level of categorization. Over four successive weeks, 12 lambs were conditioned against either a freshly cut grass (tall fescue—Festuca arundinacea, N = 6) or legume species (sainfoin—Onobrychis viciifolia, N = 6) using a negative post-ingestive stimulus (lithium chloride) on day 1. Preference of all lambs between another grass (cocksfoot—Dactylis glomerata) and another legume (alfalfa—Medicago sativa) was assessed on day 3 by measuring their relative consumptions. Preference for alfalfa progressively became lower for lambs that were conditioned against sainfoin than against tall fescue, indicating that lambs generalized the aversion between species along some perceptual gradient and classed the considered grasses and legumes in distinct categories. Beyond this original result, the question now is to identify which specific plant characteristics or functional traits the animals rely on in order to form categories.
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Herbranson WT, Schroeder J (2010) Are birds smarter than mathematicians? Pigeons (Columba livia) perform optimally on a version of the Monty Hall Dilemma. Journal of Comparative Psychology, 124(1): 1-13. doi: 10.1037/a0017703
Abstract
The “Monty Hall Dilemma” (MHD) is a well known probability puzzle in which a player tries to guess which of three doors conceals a desirable prize. After an initial choice is made, one of the remaining doors is opened, revealing no prize. The player is then given the option of staying with their initial guess or switching to the other unopened door. Most people opt to stay with their initial guess, despite the fact that switching doubles the probability of winning. A series of experiments investigated whether pigeons (Columba livia), like most humans, would fail to maximize their expected winnings in a version of the MHD. Birds completed multiple trials of a standard MHD, with the three response keys in an operant chamber serving as the three doors and access to mixed grain as the prize. Across experiments, the probability of gaining reinforcement for switching and staying was manipulated, and birds adjusted their probability of switching and staying to approximate the optimal strategy. Replication of the procedure with human participants showed that humans failed to adopt optimal strategies, even with extensive training
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Bird CD and Emery NJ (2009) Rooks Use Stones to Raise the Water Level to Reach a Floating Worm. Current Biology 19(16): 1410-1414 doi:10.1016/j.cub.2009.07.033
Abstract
In Aesop's fable “The Crow and the Pitcher,” a thirsty crow uses stones to raise the level of water in a pitcher and quench its thirst. A number of corvids have been found to use tools in the wild [1,2,3,4], and New Caledonian crows appear to understand the functional properties of tools and solve complex physical problems via causal and analogical reasoning [5,6,7,8,9,10,11]. The rook, another member of the corvid family that does not appear to use tools in the wild, also appears able to solve non-tool-related problems via similar reasoning [12]. Here, we present evidence that captive rooks are also able to solve a complex problem by using tools. We presented four captive rooks with a problem analogous to Aesop's fable: raising the level of water so that a floating worm moved into reach. All four subjects solved the problem with an appreciation of precisely how many stones were needed. Three subjects also rapidly learned to use large stones over small ones, and that sawdust cannot be manipulated in the same manner as water. This behavior demonstrates a flexible ability to use tools, a finding with implications for the evolution of tool use and cognition in animals.
Something light to start off Monday morning: Orangutan cools off with face cloth
Thanks to Mark W for the link
Saturday, August 20, 2011
Dr. Mitani's NYTimes Op- Ed:Fearing a Planet Without Apes
From the NYTimes.com
by JOHN C MITANI
VIEWERS of this summer’s Hollywood blockbuster “Rise of the Planet of the Apes” may be surprised to learn that before our earliest ancestors arrived on the scene roughly seven million years ago, apes really did rule the planet. As many as 40 kinds roamed Eurasia and Africa between 10 and 25 million years ago. Only five types remain. Two live in Asia, the gibbon and orangutan; another three, the chimpanzee, bonobo and gorilla, dwell in Africa. All five are endangered, several critically so. All may face extinction.
A decade ago, Congress stepped forward with a relatively cheap but vitally important effort to protect these apes through innovative conservation programs in Africa and Asia that combined taxpayer dollars with private money. But attempts to reauthorize the Great Apes Conservation Fund have gotten stuck in Congress and may become a victim of the larger debate over the national debt.
Hollywood’s depiction of apes as cunning — if not conniving — creatures comes close to reality. Fifty years ago, Jane Goodall’s observations of chimpanzees’ using tools and eating meat demonstrated just how similar apes are to humans. Subsequent fieldwork has underscored this point.
Gibbons, long thought to be monogamous, occasionally mate with individuals outside their group. Orangutans fashion tools to extract seeds that are otherwise difficult to obtain. Gorillas engage in conversational vocal exchanges. Bonobos appear to have sex not only to reproduce but also to relieve stress. Male chimpanzees form coalitions to kill their neighbors and take over their territory. If all of this seems human, there is a good reason: The apes are our closest living relatives, and in anatomy, genetics and behavior, they are much more similar to us than they are to other animals.
Apes fascinate and captivate us like no other species. They are prime attractions at zoos, and scientists from disciplines ranging from anthropology to biology and psychology study them closely in captivity and in the wild. As our first cousins in the primate family, apes help us to understand what makes us human.
I have been lucky to study all five kinds of apes during 33 years of fieldwork in Africa and Asia. When I look into the eyes of an ape, something stares back at me that seems familiar. Perhaps it is a shock of recognition, or a thoughtfulness not seen in the eyes of a frog, bird or cat. The penetrating stare makes me wonder, “What is this individual thinking?”
But as the human population expands, ape numbers continue to dwindle. In previous versions of the “Planet of the Apes” films, greed and consumption by humanlike apes threatened the world. In reality, it is these all-too-human traits that imperil apes.
Habitat destruction because of human activity, including logging, oil exploration and subsistence farming, is the biggest concern. Hunting is another major problem, especially in West and Central Africa, where a thriving “bush meat” trade severely threatens African apes. Poachers are now entering once-impenetrable forests on roads built for loggers and miners. Recently, periodic outbreaks of deadly diseases that can infect humans and apes, like Ebola, have begun to ravage populations of chimpanzees and gorillas.
The Great Apes Conservation Act, enacted in 2000, authorized the spending of $5 million annually over five years to help protect apes in the wild. The act was re-authorized in 2005 for another five years. The program matches public with private dollars to maximize the impact. Since 2006, for example, $21 million in federal dollars spent by the Great Ape Conservation Fund generated an additional $25 million in private grants and support from other governments.
The federal money may not sound like much in this era of “big science.” But those dollars have gone a long way to protect apes in countries that are desperately poor and politically volatile. The money pays for protecting habitat, battling poachers and educating local populations about the importance of these apes.
For instance, in Indonesia, where habitat loss threatens the few remaining populations of orangutans, money has been earmarked to block the conversion of forests to commercial oil palm and rubber plantations. In Congo, home to the extremely rare mountain gorilla, alternative fuels have been introduced to discourage the cutting of forests for charcoal production. In Gabon, the program has paid for law enforcement training for park rangers battling poachers. The list goes on. In all, last year, the Great Apes Conservation Fund helped to underwrite more than 50 programs in 7 Asian and 12 African countries. If Congress does not reauthorize the act, it could make it much harder to continue even the modest appropriations the great apes fund now receives.
A planet without apes is not sci-fi fantasy. If we do not take action now, sometime in the future, as Hollywood continues to produce sequels to the classic 1968 film, our children and our children’s children will ask with wonder, and perhaps a certain amount of anger, why we stood by idly while these remarkable creatures were driven to extinction.
(John C. Mitani is a professor of anthropology at the University of Michigan.)
Thursday, August 18, 2011
*updated* Hysteria trailer
a cheeky movie about a key moment in the study of human sexuality
*updated*
a few more interesting things came out today in case you are interested in female sexuality
a TEDx talk on female orgasm
and a documentary on Persistent Sexual Arousal Syndrome (which can be found at TOP DOCUMENTARY FILMS)
*updated*
a few more interesting things came out today in case you are interested in female sexuality
a TEDx talk on female orgasm
and a documentary on Persistent Sexual Arousal Syndrome (which can be found at TOP DOCUMENTARY FILMS)
*updated*: Family Dog Rescues 6-Year-Old Girl from River Drowning
updated august 19th 2011 - read the comment below, i totally fell for this one, my BS detector was on extremely low....
from the Morton Report via 27b/6
from the Morton Report via 27b/6
by Holly Thorne
On August 17, Tom and Marie Morgan of Ridgefield, Washington were walking along the edge of a tributary of the Lewis River with their six year-old daughter Taylor and family dog Maggie. The river was in full flow due to recent heavy rains. As Taylor ran forward to throw a rock into the river, the bank collapsed and, falling into the rushing torrent, Taylor was quickly swept away.
"I couldn't keep up with her," said her father, "the water was too quick." I was running as fast as I could along the edge when Maggie bolted past me for about 30 yards and then leaped into the river. I lost sight of both of them for a second and then I saw Maggie with Taylor's jacket collar in her mouth trying to swim towards the bank. The river took them down about another hundred yards before Maggie was able to reach the bank. Even though they went under a few times she didn't let go once. If it hadn't been for Maggie, we would have lost our daughter."
An eyewitness who was jogging nearby when the incident happened said, "The dog sprinted and jumped about 12 feet out into the river just in front of the child. They both went under and when they came up the dog had her jacket in its mouth and was dragging her to the bank. The dad ran into the water's edge and grabbed the other side of the child's jacket and they both dragged her up onto the grass. I have never seen anything like it."
Sergeant Michael Brodie of the local police department said that in twenty years on the force he had not seen anything like it either.
"I have never heard of a dog jumping into a river to save a child before. The family is very lucky to own a dog with this degree of devotion. When I took the report at the family's home, the dog sat there looking back and forth between me and Taylor and I could sense something extremely unusual between them."
Taylor's father Tom says that it is not the first time Maggie has displayed an unusual degree of devotion towards Taylor.
"Maggie never lets her out of her sight. About two years ago she rushed into the house, breaking the screen, barking as if she had gone crazy. She is usually very gentle and quiet. When my wife and I rushed to see what was happening she ran out into the yard where we found Taylor lying on the grass having trouble breathing. She had been stung on the neck and is highly allergic to bees."
Maggie has been a member of the family since Taylor was just two years old. "We visited an animal shelter and were walking down a row of cages and all the other dogs were either barking or running around but one was just sitting quietly in the middle of its cage as if waiting and Taylor stopped and said, "Hello Maggie, we're taking you home."
The parents don't know where Taylor got the name from but said it just stuck. "We have always known there was an unusual bond between them. When Taylor was younger and first walking, Maggie would move toys out of her path and always sleeps just outside her bedroom door as if on guard."
When asked about her river rescue, Taylor responded "Maggie loves me."
Today, the Morgan family received notice that Maggie has been nominated for a Commendation of Bravery by the police department. Unfortunately, the medal may be given posthumously.
"We found out last month that Maggie has been diagnosed with Hemangiosarcoma cancer and will not be with us in a few months; we haven't told Taylor yet as she will be devastated. It will be the hardest thing we have ever had to do. The two have an inseparable bond that is based on real love. We owe our daughter's life to her.
On August 17, Tom and Marie Morgan of Ridgefield, Washington were walking along the edge of a tributary of the Lewis River with their six year-old daughter Taylor and family dog Maggie. The river was in full flow due to recent heavy rains. As Taylor ran forward to throw a rock into the river, the bank collapsed and, falling into the rushing torrent, Taylor was quickly swept away.
"I couldn't keep up with her," said her father, "the water was too quick." I was running as fast as I could along the edge when Maggie bolted past me for about 30 yards and then leaped into the river. I lost sight of both of them for a second and then I saw Maggie with Taylor's jacket collar in her mouth trying to swim towards the bank. The river took them down about another hundred yards before Maggie was able to reach the bank. Even though they went under a few times she didn't let go once. If it hadn't been for Maggie, we would have lost our daughter."
An eyewitness who was jogging nearby when the incident happened said, "The dog sprinted and jumped about 12 feet out into the river just in front of the child. They both went under and when they came up the dog had her jacket in its mouth and was dragging her to the bank. The dad ran into the water's edge and grabbed the other side of the child's jacket and they both dragged her up onto the grass. I have never seen anything like it."
Sergeant Michael Brodie of the local police department said that in twenty years on the force he had not seen anything like it either.
"I have never heard of a dog jumping into a river to save a child before. The family is very lucky to own a dog with this degree of devotion. When I took the report at the family's home, the dog sat there looking back and forth between me and Taylor and I could sense something extremely unusual between them."
Taylor's father Tom says that it is not the first time Maggie has displayed an unusual degree of devotion towards Taylor.
"Maggie never lets her out of her sight. About two years ago she rushed into the house, breaking the screen, barking as if she had gone crazy. She is usually very gentle and quiet. When my wife and I rushed to see what was happening she ran out into the yard where we found Taylor lying on the grass having trouble breathing. She had been stung on the neck and is highly allergic to bees."
Maggie has been a member of the family since Taylor was just two years old. "We visited an animal shelter and were walking down a row of cages and all the other dogs were either barking or running around but one was just sitting quietly in the middle of its cage as if waiting and Taylor stopped and said, "Hello Maggie, we're taking you home."
The parents don't know where Taylor got the name from but said it just stuck. "We have always known there was an unusual bond between them. When Taylor was younger and first walking, Maggie would move toys out of her path and always sleeps just outside her bedroom door as if on guard."
When asked about her river rescue, Taylor responded "Maggie loves me."
Today, the Morgan family received notice that Maggie has been nominated for a Commendation of Bravery by the police department. Unfortunately, the medal may be given posthumously.
"We found out last month that Maggie has been diagnosed with Hemangiosarcoma cancer and will not be with us in a few months; we haven't told Taylor yet as she will be devastated. It will be the hardest thing we have ever had to do. The two have an inseparable bond that is based on real love. We owe our daughter's life to her.
Will power and decision making get harder as the day goes on and glucose is depleted
REALLY well written and researched article on decision making and how it affects all aspects of our lives-MA
From the New York Times
Do You Suffer From Decision Fatigue?
By JOHN TIERNEY
Do You Suffer From Decision Fatigue?
By JOHN TIERNEY
Three men doing time in Israeli prisons recently appeared before a parole board consisting of a judge, a criminologist and a social worker. The three prisoners had completed at least two-thirds of their sentences, but the parole board granted freedom to only one of them. Guess which one:
Case 1 (heard at 8:50 a.m.): An Arab Israeli serving a 30-month sentence for fraud.
Case 2 (heard at 3:10 p.m.): A Jewish Israeli serving a 16-month sentence for assault.
Case 3 (heard at 4:25 p.m.): An Arab Israeli serving a 30-month sentence for fraud.
There was a pattern to the parole board’s decisions, but it wasn’t related to the men’s ethnic backgrounds, crimes or sentences. It was all about timing, as researchers discovered by analyzing more than 1,100 decisions over the course of a year. Judges, who would hear the prisoners’ appeals and then get advice from the other members of the board, approved parole in about a third of the cases, but the probability of being paroled fluctuated wildly throughout the day. Prisoners who appeared early in the morning received parole about 70 percent of the time, while those who appeared late in the day were paroled less than 10 percent of the time.
The odds favored the prisoner who appeared at 8:50 a.m. — and he did in fact receive parole. But even though the other Arab Israeli prisoner was serving the same sentence for the same crime — fraud — the odds were against him when he appeared (on a different day) at 4:25 in the afternoon. He was denied parole, as was the Jewish Israeli prisoner at 3:10 p.m, whose sentence was shorter than that of the man who was released. They were just asking for parole at the wrong time of day.
There was nothing malicious or even unusual about the judges’ behavior, which was reported earlier this year by Jonathan Levav of Stanford and Shai Danziger of Ben-Gurion University. The judges’ erratic judgment was due to the occupational hazard of being, as George W. Bush once put it, “the decider.” The mental work of ruling on case after case, whatever the individual merits, wore them down. This sort of decision fatigue can make quarterbacks prone to dubious choices late in the game and C.F.O.’s prone to disastrous dalliances late in the evening. It routinely warps the judgment of everyone, executive and nonexecutive, rich and poor — in fact, it can take a special toll on the poor. Yet few people are even aware of it, and researchers are only beginning to understand why it happens and how to counteract it.
Decision fatigue helps explain why ordinarily sensible people get angry at colleagues and families, splurge on clothes, buy junk food at the supermarket and can’t resist the dealer’s offer to rustproof their new car. No matter how rational and high-minded you try to be, you can’t make decision after decision without paying a biological price. It’s different from ordinary physical fatigue — you’re not consciously aware of being tired — but you’re low on mental energy. The more choices you make throughout the day, the harder each one becomes for your brain, and eventually it looks for shortcuts, usually in either of two very different ways. One shortcut is to become reckless: to act impulsively instead of expending the energy to first think through the consequences. (Sure, tweet that photo! What could go wrong?) The other shortcut is the ultimate energy saver: do nothing. Instead of agonizing over decisions, avoid any choice. Ducking a decision often creates bigger problems in the long run, but for the moment, it eases the mental strain. You start to resist any change, any potentially risky move — like releasing a prisoner who might commit a crime. So the fatigued judge on a parole board takes the easy way out, and the prisoner keeps doing time.
Decision fatigue is the newest discovery involving a phenomenon called ego depletion, a term coined by the social psychologist Roy F. Baumeister in homage to a Freudian hypothesis. Freud speculated that the self, or ego, depended on mental activities involving the transfer of energy. He was vague about the details, though, and quite wrong about some of them (like his idea that artists “sublimate” sexual energy into their work, which would imply that adultery should be especially rare at artists’ colonies). Freud’s energy model of the self was generally ignored until the end of the century, when Baumeister began studying mental discipline in a series of experiments, first at Case Western and then at Florida State University.
These experiments demonstrated that there is a finite store of mental energy for exerting self-control. When people fended off the temptation to scarf down M&M’s or freshly baked chocolate-chip cookies, they were then less able to resist other temptations. When they forced themselves to remain stoic during a tearjerker movie, afterward they gave up more quickly on lab tasks requiring self-discipline, like working on a geometry puzzle or squeezing a hand-grip exerciser. Willpower turned out to be more than a folk concept or a metaphor. It really was a form of mental energy that could be exhausted. The experiments confirmed the 19th-century notion of willpower being like a muscle that was fatigued with use, a force that could be conserved by avoiding temptation. To study the process of ego depletion, researchers concentrated initially on acts involving self-control — the kind of self-discipline popularly associated with willpower, like resisting a bowl of ice cream. They weren’t concerned with routine decision-making, like choosing between chocolate and vanilla, a mental process that they assumed was quite distinct and much less strenuous. Intuitively, the chocolate-vanilla choice didn’t appear to require willpower.
But then a postdoctoral fellow, Jean Twenge, started working at Baumeister’s laboratory right after planning her wedding. As Twenge studied the results of the lab’s ego-depletion experiments, she remembered how exhausted she felt the evening she and her fiancé went through the ritual of registering for gifts. Did they want plain white china or something with a pattern? Which brand of knives? How many towels? What kind of sheets? Precisely how many threads per square inch?
“By the end, you could have talked me into anything,” Twenge told her new colleagues. The symptoms sounded familiar to them too, and gave them an idea. A nearby department store was holding a going-out-of-business sale, so researchers from the lab went off to fill their car trunks with simple products — not exactly wedding-quality gifts, but sufficiently appealing to interest college students. When they came to the lab, the students were told they would get to keep one item at the end of the experiment, but first they had to make a series of choices. Would they prefer a pen or a candle? A vanilla-scented candle or an almond-scented one? A candle or a T-shirt? A black T-shirt or a red T-shirt? A control group, meanwhile — let’s call them the nondeciders — spent an equally long period contemplating all these same products without having to make any choices. They were asked just to give their opinion of each product and report how often they had used such a product in the last six months.
Afterward, all the participants were given one of the classic tests of self-control: holding your hand in ice water for as long as you can. The impulse is to pull your hand out, so self-discipline is needed to keep the hand underwater. The deciders gave up much faster; they lasted 28 seconds, less than half the 67-second average of the nondeciders. Making all those choices had apparently sapped their willpower, and it wasn’t an isolated effect. It was confirmed in other experiments testing students after they went through exercises like choosing courses from the college catalog.
For a real-world test of their theory, the lab’s researchers went into that great modern arena of decision making: the suburban mall. They interviewed shoppers about their experiences in the stores that day and then asked them to solve some simple arithmetic problems. The researchers politely asked them to do as many as possible but said they could quit at any time. Sure enough, the shoppers who had already made the most decisions in the stores gave up the quickest on the math problems. When you shop till you drop, your willpower drops, too.
Any decision, whether it’s what pants to buy or whether to start a war, can be broken down into what psychologists call the Rubicon model of action phases, in honor of the river that separated Italy from the Roman province of Gaul. When Caesar reached it in 49 B.C., on his way home after conquering the Gauls, he knew that a general returning to Rome was forbidden to take his legions across the river with him, lest it be considered an invasion of Rome. Waiting on the Gaul side of the river, he was in the “predecisional phase” as he contemplated the risks and benefits of starting a civil war. Then he stopped calculating and crossed the Rubicon, reaching the “postdecisional phase,” which Caesar defined much more felicitously: “The die is cast.”
The whole process could deplete anyone’s willpower, but which phase of the decision-making process was most fatiguing? To find out, Kathleen Vohs, a former colleague of Baumeister’s now at the University of Minnesota, performed an experiment using the self-service Web site of Dell Computers. One group in the experiment carefully studied the advantages and disadvantages of various features available for a computer — the type of screen, the size of the hard drive, etc. — without actually making a final decision on which ones to choose. A second group was given a list of predetermined specifications and told to configure a computer by going through the laborious, step-by-step process of locating the specified features among the arrays of options and then clicking on the right ones. The purpose of this was to duplicate everything that happens in the postdecisional phase, when the choice is implemented. The third group had to figure out for themselves which features they wanted on their computers and go through the process of choosing them; they didn’t simply ponder options (like the first group) or implement others’ choices (like the second group). They had to cast the die, and that turned out to be the most fatiguing task of all. When self-control was measured, they were the one who were most depleted, by far.
The experiment showed that crossing the Rubicon is more tiring than anything that happens on either bank — more mentally fatiguing than sitting on the Gaul side contemplating your options or marching on Rome once you’ve crossed. As a result, someone without Caesar’s willpower is liable to stay put. To a fatigued judge, denying parole seems like the easier call not only because it preserves the status quo and eliminates the risk of a parolee going on a crime spree but also because it leaves more options open: the judge retains the option of paroling the prisoner at a future date without sacrificing the option of keeping him securely in prison right now. Part of the resistance against making decisions comes from our fear of giving up options. The word “decide” shares an etymological root with “homicide,” the Latin word “caedere,” meaning “to cut down” or “to kill,” and that loss looms especially large when decision fatigue sets in.
Once you’re mentally depleted, you become reluctant to make trade-offs, which involve a particularly advanced and taxing form of decision making. In the rest of the animal kingdom, there aren’t a lot of protracted negotiations between predators and prey. To compromise is a complex human ability and therefore one of the first to decline when willpower is depleted. You become what researchers call a cognitive miser, hoarding your energy. If you’re shopping, you’re liable to look at only one dimension, like price: just give me the cheapest. Or you indulge yourself by looking at quality: I want the very best (an especially easy strategy if someone else is paying). Decision fatigue leaves you vulnerable to marketers who know how to time their sales, as Jonathan Levav, the Stanford professor, demonstrated in experiments involving tailored suits and new cars.
The idea for these experiments also happened to come in the preparations for a wedding, a ritual that seems to be the decision-fatigue equivalent of Hell Week. At his fiancée’s suggestion, Levav visited a tailor to have a bespoke suit made and began going through the choices of fabric, type of lining and style of buttons, lapels, cuffs and so forth.
“By the time I got through the third pile of fabric swatches, I wanted to kill myself,” Levav recalls. “I couldn’t tell the choices apart anymore. After a while my only response to the tailor became ‘What do you recommend?’ I just couldn’t take it.”
Levav ended up not buying any kind of bespoke suit (the $2,000 price made that decision easy enough), but he put the experience to use in a pair of experiments conducted with Mark Heitmann, then at Christian-Albrechts University in Germany; Andreas Herrmann, at the University of St. Gallen in Switzerland; and Sheena Iyengar, of Columbia. One involved asking M.B.A. students in Switzerland to choose a bespoke suit; the other was conducted at German car dealerships, where customers ordered options for their new sedans. The car buyers — and these were real customers spending their own money — had to choose, for instance, among 4 styles of gearshift knobs, 13 kinds of wheel rims, 25 configurations of the engine and gearbox and a palette of 56 colors for the interior.
As they started picking features, customers would carefully weigh the choices, but as decision fatigue set in, they would start settling for whatever the default option was. And the more tough choices they encountered early in the process — like going through those 56 colors to choose the precise shade of gray or brown — the quicker people became fatigued and settled for the path of least resistance by taking the default option. By manipulating the order of the car buyers’ choices, the researchers found that the customers would end up settling for different kinds of options, and the average difference totaled more than 1,500 euros per car (about $2,000 at the time). Whether the customers paid a little extra for fancy wheel rims or a lot extra for a more powerful engine depended on when the choice was offered and how much willpower was left in the customer.
Similar results were found in the experiment with custom-made suits: once decision fatigue set in, people tended to settle for the recommended option. When they were confronted early on with the toughest decisions — the ones with the most options, like the 100 fabrics for the suit — they became fatigued more quickly and also reported enjoying the shopping experience less.
Shopping can be especially tiring for the poor, who have to struggle continually with trade-offs. Most of us in America won’t spend a lot of time agonizing over whether we can afford to buy soap, but it can be a depleting choice in rural India. Dean Spears, an economist at Princeton, offered people in 20 villages in Rajasthan in northwestern India the chance to buy a couple of bars of brand-name soap for the equivalent of less than 20 cents. It was a steep discount off the regular price, yet even that sum was a strain for the people in the 10 poorest villages. Whether or not they bought the soap, the act of making the decision left them with less willpower, as measured afterward in a test of how long they could squeeze a hand grip. In the slightly more affluent villages, people’s willpower wasn’t affected significantly. Because they had more money, they didn’t have to spend as much effort weighing the merits of the soap versus, say, food or medicine.
Spears and other researchers argue that this sort of decision fatigue is a major — and hitherto ignored — factor in trapping people in poverty. Because their financial situation forces them to make so many trade-offs, they have less willpower to devote to school, work and other activities that might get them into the middle class. It’s hard to know exactly how important this factor is, but there’s no doubt that willpower is a special problem for poor people. Study after study has shown that low self-control correlates with low income as well as with a host of other problems, including poor achievement in school, divorce, crime, alcoholism and poor health. Lapses in self-control have led to the notion of the “undeserving poor” — epitomized by the image of the welfare mom using food stamps to buy junk food — but Spears urges sympathy for someone who makes decisions all day on a tight budget. In one study, he found that when the poor and the rich go shopping, the poor are much more likely to eat during the shopping trip. This might seem like confirmation of their weak character — after all, they could presumably save money and improve their nutrition by eating meals at home instead of buying ready-to-eat snacks like Cinnabons, which contribute to the higher rate of obesity among the poor. But if a trip to the supermarket induces more decision fatigue in the poor than in the rich — because each purchase requires more mental trade-offs — by the time they reach the cash register, they’ll have less willpower left to resist the Mars bars and Skittles. Not for nothing are these items called impulse purchases.
And this isn’t the only reason that sweet snacks are featured prominently at the cash register, just when shoppers are depleted after all their decisions in the aisles. With their willpower reduced, they’re more likely to yield to any kind of temptation, but they’re especially vulnerable to candy and soda and anything else offering a quick hit of sugar. While supermarkets figured this out a long time ago, only recently did researchers discover why.
The discovery was an accident resulting from a failed experiment at Baumeister’s lab. The researchers set out to test something called the Mardi Gras theory — the notion that you could build up willpower by first indulging yourself in pleasure, the way Mardi Gras feasters do just before the rigors of Lent. In place of a Fat Tuesday breakfast, the chefs in the lab at Florida State whipped up lusciously thick milkshakes for a group of subjects who were resting in between two laboratory tasks requiring willpower. Sure enough, the delicious shakes seemed to strengthen willpower by helping people perform better than expected on the next task. So far, so good. But the experiment also included a control group of people who were fed a tasteless concoction of low-fat dairy glop. It provided them with no pleasure, yet it produced similar improvements in self-control. The Mardi Gras theory looked wrong. Besides tragically removing an excuse for romping down the streets of New Orleans, the result was embarrassing for the researchers. Matthew Gailliot, the graduate student who ran the study, stood looking down at his shoes as he told Baumeister about the fiasco.
Baumeister tried to be optimistic. Maybe the study wasn’t a failure. Something had happened, after all. Even the tasteless glop had done the job, but how? If it wasn’t the pleasure, could it be the calories? At first the idea seemed a bit daft. For decades, psychologists had been studying performance on mental tasks without worrying much about the results being affected by dairy-product consumption. They liked to envision the human mind as a computer, focusing on the way it processed information. In their eagerness to chart the human equivalent of the computer’s chips and circuits, most psychologists neglected one mundane but essential part of the machine: the power supply. The brain, like the rest of the body, derived energy from glucose, the simple sugar manufactured from all kinds of foods. To establish cause and effect, researchers at Baumeister’s lab tried refueling the brain in a series of experiments involving lemonade mixed either with sugar or with a diet sweetener. The sugary lemonade provided a burst of glucose, the effects of which could be observed right away in the lab; the sugarless variety tasted quite similar without providing the same burst of glucose. Again and again, the sugar restored willpower, but the artificial sweetener had no effect. The glucose would at least mitigate the ego depletion and sometimes completely reverse it. The restored willpower improved people’s self-control as well as the quality of their decisions: they resisted irrational bias when making choices, and when asked to make financial decisions, they were more likely to choose the better long-term strategy instead of going for a quick payoff. The ego-depletion effect was even demonstrated with dogs in two studies by Holly Miller and Nathan DeWall at the University of Kentucky. After obeying sit and stay commands for 10 minutes, the dogs performed worse on self-control tests and were also more likely to make the dangerous decision to challenge another dog’s turf. But a dose of glucose restored their willpower.
Despite this series of findings, brain researchers still had some reservations about the glucose connection. Skeptics pointed out that the brain’s overall use of energy remains about the same regardless of what a person is doing, which doesn’t square easily with the notion of depleted energy affecting willpower. Among the skeptics was Todd Heatherton, who worked with Baumeister early in his career and eventually wound up at Dartmouth, where he became a pioneer of what is called social neuroscience: the study of links between brain processes and social behavior. He believed in ego depletion, but he didn’t see how this neural process could be caused simply by variations in glucose levels. To observe the process — and to see if it could be reversed by glucose — he and his colleagues recruited 45 female dieters and recorded images of their brains as they reacted to pictures of food. Next the dieters watched a comedy video while forcing themselves to suppress their laughter — a standard if cruel way to drain mental energy and induce ego depletion. Then they were again shown pictures of food, and the new round of brain scans revealed the effects of ego depletion: more activity in the nucleus accumbens, the brain’s reward center, and a corresponding decrease in the amygdala, which ordinarily helps control impulses. The food’s appeal registered more strongly while impulse control weakened — not a good combination for anyone on a diet. But suppose people in this ego-depleted state got a quick dose of glucose? What would a scan of their brains reveal?
The results of the experiment were announced in January, during Heatherton’s speech accepting the leadership of the Society for Personality and Social Psychology, the world’s largest group of social psychologists. In his presidential address at the annual meeting in San Antonio, Heatherton reported that administering glucose completely reversed the brain changes wrought by depletion — a finding, he said, that thoroughly surprised him. Heatherton’s results did much more than provide additional confirmation that glucose is a vital part of willpower; they helped solve the puzzle over how glucose could work without global changes in the brain’s total energy use. Apparently ego depletion causes activity to rise in some parts of the brain and to decline in others. Your brain does not stop working when glucose is low. It stops doing some things and starts doing others. It responds more strongly to immediate rewards and pays less attention to long-term prospects.
The discoveries about glucose help explain why dieting is a uniquely difficult test of self-control — and why even people with phenomenally strong willpower in the rest of their lives can have such a hard time losing weight. They start out the day with virtuous intentions, resisting croissants at breakfast and dessert at lunch, but each act of resistance further lowers their willpower. As their willpower weakens late in the day, they need to replenish it. But to resupply that energy, they need to give the body glucose. They’re trapped in a nutritional catch-22:
1. In order not to eat, a dieter needs willpower.
2. In order to have willpower, a dieter needs to eat.
As the body uses up glucose, it looks for a quick way to replenish the fuel, leading to a craving for sugar. After performing a lab task requiring self-control, people tend to eat more candy but not other kinds of snacks, like salty, fatty potato chips. The mere expectation of having to exert self-control makes people hunger for sweets. A similar effect helps explain why many women yearn for chocolate and other sugary treats just before menstruation: their bodies are seeking a quick replacement as glucose levels fluctuate. A sugar-filled snack or drink will provide a quick improvement in self-control (that’s why it’s convenient to use in experiments), but it’s just a temporary solution. The problem is that what we identify as sugar doesn’t help as much over the course of the day as the steadier supply of glucose we would get from eating proteins and other more nutritious foods.
The benefits of glucose were unmistakable in the study of the Israeli parole board. In midmorning, usually a little before 10:30, the parole board would take a break, and the judges would be served a sandwich and a piece of fruit. The prisoners who appeared just before the break had only about a 20 percent chance of getting parole, but the ones appearing right after had around a 65 percent chance. The odds dropped again as the morning wore on, and prisoners really didn’t want to appear just before lunch: the chance of getting parole at that time was only 10 percent. After lunch it soared up to 60 percent, but only briefly. Remember that Jewish Israeli prisoner who appeared at 3:10 p.m. and was denied parole from his sentence for assault? He had the misfortune of being the sixth case heard after lunch. But another Jewish Israeli prisoner serving the same sentence for the same crime was lucky enough to appear at 1:27 p.m., the first case after lunch, and he was rewarded with parole. It must have seemed to him like a fine example of the justice system at work, but it probably had more to do with the judge’s glucose levels.
It’s simple enough to imagine reforms for the parole board in Israel — like, say, restricting each judge’s shift to half a day, preferably in the morning, interspersed with frequent breaks for food and rest. But it’s not so obvious what to do with the decision fatigue affecting the rest of society. Even if we could all afford to work half-days, we would still end up depleting our willpower all day long, as Baumeister and his colleagues found when they went into the field in Würzburg in central Germany. The psychologists gave preprogrammed BlackBerrys to more than 200 people going about their daily routines for a week. The phones went off at random intervals, prompting the people to report whether they were currently experiencing some sort of desire or had recently felt a desire. The painstaking study, led by Wilhelm Hofmann, then at the University of Würzburg, collected more than 10,000 momentary reports from morning until midnight.
Desire turned out to be the norm, not the exception. Half the people were feeling some desire when their phones went off — to snack, to goof off, to express their true feelings to their bosses — and another quarter said they had felt a desire in the past half-hour. Many of these desires were ones that the men and women were trying to resist, and the more willpower people expended, the more likely they became to yield to the next temptation that came along. When faced with a new desire that produced some I-want-to-but-I-really-shouldn’t sort of inner conflict, they gave in more readily if they had already fended off earlier temptations, particularly if the new temptation came soon after a previously reported one.
The results suggested that people spend between three and four hours a day resisting desire. Put another way, if you tapped four or five people at any random moment of the day, one of them would be using willpower to resist a desire. The most commonly resisted desires in the phone study were the urges to eat and sleep, followed by the urge for leisure, like taking a break from work by doing a puzzle or playing a game instead of writing a memo. Sexual urges were next on the list of most-resisted desires, a little ahead of urges for other kinds of interactions, like checking Facebook. To ward off temptation, people reported using various strategies. The most popular was to look for a distraction or to undertake a new activity, although sometimes they tried suppressing it directly or simply toughing their way through it. Their success was decidedly mixed. They were pretty good at avoiding sleep, sex and the urge to spend money, but not so good at resisting the lure of television or the Web or the general temptation to relax instead of work.
We have no way of knowing how much our ancestors exercised self-control in the days before BlackBerrys and social psychologists, but it seems likely that many of them were under less ego-depleting strain. When there were fewer decisions, there was less decision fatigue. Today we feel overwhelmed because there are so many choices. Your body may have dutifully reported to work on time, but your mind can escape at any instant. A typical computer user looks at more than three dozen Web sites a day and gets fatigued by the continual decision making — whether to keep working on a project, check out TMZ, follow a link to YouTube or buy something on Amazon. You can do enough damage in a 10-minute online shopping spree to wreck your budget for the rest of the year.
The cumulative effect of these temptations and decisions isn’t intuitively obvious. Virtually no one has a gut-level sense of just how tiring it is to decide. Big decisions, small decisions, they all add up. Choosing what to have for breakfast, where to go on vacation, whom to hire, how much to spend — these all deplete willpower, and there’s no telltale symptom of when that willpower is low. It’s not like getting winded or hitting the wall during a marathon. Ego depletion manifests itself not as one feeling but rather as a propensity to experience everything more intensely. When the brain’s regulatory powers weaken, frustrations seem more irritating than usual. Impulses to eat, drink, spend and say stupid things feel more powerful (and alcohol causes self-control to decline further). Like those dogs in the experiment, ego-depleted humans become more likely to get into needless fights over turf. In making decisions, they take illogical shortcuts and tend to favor short-term gains and delayed costs. Like the depleted parole judges, they become inclined to take the safer, easier option even when that option hurts someone else.
“Good decision making is not a trait of the person, in the sense that it’s always there,” Baumeister says. “It’s a state that fluctuates.” His studies show that people with the best self-control are the ones who structure their lives so as to conserve willpower. They don’t schedule endless back-to-back meetings. They avoid temptations like all-you-can-eat buffets, and they establish habits that eliminate the mental effort of making choices. Instead of deciding every morning whether or not to force themselves to exercise, they set up regular appointments to work out with a friend. Instead of counting on willpower to remain robust all day, they conserve it so that it’s available for emergencies and important decisions.
“Even the wisest people won’t make good choices when they’re not rested and their glucose is low,” Baumeister points out. That’s why the truly wise don’t restructure the company at 4 p.m. They don’t make major commitments during the cocktail hour. And if a decision must be made late in the day, they know not to do it on an empty stomach. “The best decision makers,” Baumeister says, “are the ones who know when not to trust themselves.”
John Tierney (tierneylab@nytimes.com) is a science columnist for The Times. His essay is adapted from a book he wrote with Roy F. Baumeister, “Willpower: Rediscovering the Greatest Human Strength,” which comes out next month.
Case 1 (heard at 8:50 a.m.): An Arab Israeli serving a 30-month sentence for fraud.
Case 2 (heard at 3:10 p.m.): A Jewish Israeli serving a 16-month sentence for assault.
Case 3 (heard at 4:25 p.m.): An Arab Israeli serving a 30-month sentence for fraud.
There was a pattern to the parole board’s decisions, but it wasn’t related to the men’s ethnic backgrounds, crimes or sentences. It was all about timing, as researchers discovered by analyzing more than 1,100 decisions over the course of a year. Judges, who would hear the prisoners’ appeals and then get advice from the other members of the board, approved parole in about a third of the cases, but the probability of being paroled fluctuated wildly throughout the day. Prisoners who appeared early in the morning received parole about 70 percent of the time, while those who appeared late in the day were paroled less than 10 percent of the time.
The odds favored the prisoner who appeared at 8:50 a.m. — and he did in fact receive parole. But even though the other Arab Israeli prisoner was serving the same sentence for the same crime — fraud — the odds were against him when he appeared (on a different day) at 4:25 in the afternoon. He was denied parole, as was the Jewish Israeli prisoner at 3:10 p.m, whose sentence was shorter than that of the man who was released. They were just asking for parole at the wrong time of day.
There was nothing malicious or even unusual about the judges’ behavior, which was reported earlier this year by Jonathan Levav of Stanford and Shai Danziger of Ben-Gurion University. The judges’ erratic judgment was due to the occupational hazard of being, as George W. Bush once put it, “the decider.” The mental work of ruling on case after case, whatever the individual merits, wore them down. This sort of decision fatigue can make quarterbacks prone to dubious choices late in the game and C.F.O.’s prone to disastrous dalliances late in the evening. It routinely warps the judgment of everyone, executive and nonexecutive, rich and poor — in fact, it can take a special toll on the poor. Yet few people are even aware of it, and researchers are only beginning to understand why it happens and how to counteract it.
Decision fatigue helps explain why ordinarily sensible people get angry at colleagues and families, splurge on clothes, buy junk food at the supermarket and can’t resist the dealer’s offer to rustproof their new car. No matter how rational and high-minded you try to be, you can’t make decision after decision without paying a biological price. It’s different from ordinary physical fatigue — you’re not consciously aware of being tired — but you’re low on mental energy. The more choices you make throughout the day, the harder each one becomes for your brain, and eventually it looks for shortcuts, usually in either of two very different ways. One shortcut is to become reckless: to act impulsively instead of expending the energy to first think through the consequences. (Sure, tweet that photo! What could go wrong?) The other shortcut is the ultimate energy saver: do nothing. Instead of agonizing over decisions, avoid any choice. Ducking a decision often creates bigger problems in the long run, but for the moment, it eases the mental strain. You start to resist any change, any potentially risky move — like releasing a prisoner who might commit a crime. So the fatigued judge on a parole board takes the easy way out, and the prisoner keeps doing time.
Decision fatigue is the newest discovery involving a phenomenon called ego depletion, a term coined by the social psychologist Roy F. Baumeister in homage to a Freudian hypothesis. Freud speculated that the self, or ego, depended on mental activities involving the transfer of energy. He was vague about the details, though, and quite wrong about some of them (like his idea that artists “sublimate” sexual energy into their work, which would imply that adultery should be especially rare at artists’ colonies). Freud’s energy model of the self was generally ignored until the end of the century, when Baumeister began studying mental discipline in a series of experiments, first at Case Western and then at Florida State University.
These experiments demonstrated that there is a finite store of mental energy for exerting self-control. When people fended off the temptation to scarf down M&M’s or freshly baked chocolate-chip cookies, they were then less able to resist other temptations. When they forced themselves to remain stoic during a tearjerker movie, afterward they gave up more quickly on lab tasks requiring self-discipline, like working on a geometry puzzle or squeezing a hand-grip exerciser. Willpower turned out to be more than a folk concept or a metaphor. It really was a form of mental energy that could be exhausted. The experiments confirmed the 19th-century notion of willpower being like a muscle that was fatigued with use, a force that could be conserved by avoiding temptation. To study the process of ego depletion, researchers concentrated initially on acts involving self-control — the kind of self-discipline popularly associated with willpower, like resisting a bowl of ice cream. They weren’t concerned with routine decision-making, like choosing between chocolate and vanilla, a mental process that they assumed was quite distinct and much less strenuous. Intuitively, the chocolate-vanilla choice didn’t appear to require willpower.
But then a postdoctoral fellow, Jean Twenge, started working at Baumeister’s laboratory right after planning her wedding. As Twenge studied the results of the lab’s ego-depletion experiments, she remembered how exhausted she felt the evening she and her fiancé went through the ritual of registering for gifts. Did they want plain white china or something with a pattern? Which brand of knives? How many towels? What kind of sheets? Precisely how many threads per square inch?
“By the end, you could have talked me into anything,” Twenge told her new colleagues. The symptoms sounded familiar to them too, and gave them an idea. A nearby department store was holding a going-out-of-business sale, so researchers from the lab went off to fill their car trunks with simple products — not exactly wedding-quality gifts, but sufficiently appealing to interest college students. When they came to the lab, the students were told they would get to keep one item at the end of the experiment, but first they had to make a series of choices. Would they prefer a pen or a candle? A vanilla-scented candle or an almond-scented one? A candle or a T-shirt? A black T-shirt or a red T-shirt? A control group, meanwhile — let’s call them the nondeciders — spent an equally long period contemplating all these same products without having to make any choices. They were asked just to give their opinion of each product and report how often they had used such a product in the last six months.
Afterward, all the participants were given one of the classic tests of self-control: holding your hand in ice water for as long as you can. The impulse is to pull your hand out, so self-discipline is needed to keep the hand underwater. The deciders gave up much faster; they lasted 28 seconds, less than half the 67-second average of the nondeciders. Making all those choices had apparently sapped their willpower, and it wasn’t an isolated effect. It was confirmed in other experiments testing students after they went through exercises like choosing courses from the college catalog.
For a real-world test of their theory, the lab’s researchers went into that great modern arena of decision making: the suburban mall. They interviewed shoppers about their experiences in the stores that day and then asked them to solve some simple arithmetic problems. The researchers politely asked them to do as many as possible but said they could quit at any time. Sure enough, the shoppers who had already made the most decisions in the stores gave up the quickest on the math problems. When you shop till you drop, your willpower drops, too.
Any decision, whether it’s what pants to buy or whether to start a war, can be broken down into what psychologists call the Rubicon model of action phases, in honor of the river that separated Italy from the Roman province of Gaul. When Caesar reached it in 49 B.C., on his way home after conquering the Gauls, he knew that a general returning to Rome was forbidden to take his legions across the river with him, lest it be considered an invasion of Rome. Waiting on the Gaul side of the river, he was in the “predecisional phase” as he contemplated the risks and benefits of starting a civil war. Then he stopped calculating and crossed the Rubicon, reaching the “postdecisional phase,” which Caesar defined much more felicitously: “The die is cast.”
The whole process could deplete anyone’s willpower, but which phase of the decision-making process was most fatiguing? To find out, Kathleen Vohs, a former colleague of Baumeister’s now at the University of Minnesota, performed an experiment using the self-service Web site of Dell Computers. One group in the experiment carefully studied the advantages and disadvantages of various features available for a computer — the type of screen, the size of the hard drive, etc. — without actually making a final decision on which ones to choose. A second group was given a list of predetermined specifications and told to configure a computer by going through the laborious, step-by-step process of locating the specified features among the arrays of options and then clicking on the right ones. The purpose of this was to duplicate everything that happens in the postdecisional phase, when the choice is implemented. The third group had to figure out for themselves which features they wanted on their computers and go through the process of choosing them; they didn’t simply ponder options (like the first group) or implement others’ choices (like the second group). They had to cast the die, and that turned out to be the most fatiguing task of all. When self-control was measured, they were the one who were most depleted, by far.
The experiment showed that crossing the Rubicon is more tiring than anything that happens on either bank — more mentally fatiguing than sitting on the Gaul side contemplating your options or marching on Rome once you’ve crossed. As a result, someone without Caesar’s willpower is liable to stay put. To a fatigued judge, denying parole seems like the easier call not only because it preserves the status quo and eliminates the risk of a parolee going on a crime spree but also because it leaves more options open: the judge retains the option of paroling the prisoner at a future date without sacrificing the option of keeping him securely in prison right now. Part of the resistance against making decisions comes from our fear of giving up options. The word “decide” shares an etymological root with “homicide,” the Latin word “caedere,” meaning “to cut down” or “to kill,” and that loss looms especially large when decision fatigue sets in.
Once you’re mentally depleted, you become reluctant to make trade-offs, which involve a particularly advanced and taxing form of decision making. In the rest of the animal kingdom, there aren’t a lot of protracted negotiations between predators and prey. To compromise is a complex human ability and therefore one of the first to decline when willpower is depleted. You become what researchers call a cognitive miser, hoarding your energy. If you’re shopping, you’re liable to look at only one dimension, like price: just give me the cheapest. Or you indulge yourself by looking at quality: I want the very best (an especially easy strategy if someone else is paying). Decision fatigue leaves you vulnerable to marketers who know how to time their sales, as Jonathan Levav, the Stanford professor, demonstrated in experiments involving tailored suits and new cars.
The idea for these experiments also happened to come in the preparations for a wedding, a ritual that seems to be the decision-fatigue equivalent of Hell Week. At his fiancée’s suggestion, Levav visited a tailor to have a bespoke suit made and began going through the choices of fabric, type of lining and style of buttons, lapels, cuffs and so forth.
“By the time I got through the third pile of fabric swatches, I wanted to kill myself,” Levav recalls. “I couldn’t tell the choices apart anymore. After a while my only response to the tailor became ‘What do you recommend?’ I just couldn’t take it.”
Levav ended up not buying any kind of bespoke suit (the $2,000 price made that decision easy enough), but he put the experience to use in a pair of experiments conducted with Mark Heitmann, then at Christian-Albrechts University in Germany; Andreas Herrmann, at the University of St. Gallen in Switzerland; and Sheena Iyengar, of Columbia. One involved asking M.B.A. students in Switzerland to choose a bespoke suit; the other was conducted at German car dealerships, where customers ordered options for their new sedans. The car buyers — and these were real customers spending their own money — had to choose, for instance, among 4 styles of gearshift knobs, 13 kinds of wheel rims, 25 configurations of the engine and gearbox and a palette of 56 colors for the interior.
As they started picking features, customers would carefully weigh the choices, but as decision fatigue set in, they would start settling for whatever the default option was. And the more tough choices they encountered early in the process — like going through those 56 colors to choose the precise shade of gray or brown — the quicker people became fatigued and settled for the path of least resistance by taking the default option. By manipulating the order of the car buyers’ choices, the researchers found that the customers would end up settling for different kinds of options, and the average difference totaled more than 1,500 euros per car (about $2,000 at the time). Whether the customers paid a little extra for fancy wheel rims or a lot extra for a more powerful engine depended on when the choice was offered and how much willpower was left in the customer.
Similar results were found in the experiment with custom-made suits: once decision fatigue set in, people tended to settle for the recommended option. When they were confronted early on with the toughest decisions — the ones with the most options, like the 100 fabrics for the suit — they became fatigued more quickly and also reported enjoying the shopping experience less.
Shopping can be especially tiring for the poor, who have to struggle continually with trade-offs. Most of us in America won’t spend a lot of time agonizing over whether we can afford to buy soap, but it can be a depleting choice in rural India. Dean Spears, an economist at Princeton, offered people in 20 villages in Rajasthan in northwestern India the chance to buy a couple of bars of brand-name soap for the equivalent of less than 20 cents. It was a steep discount off the regular price, yet even that sum was a strain for the people in the 10 poorest villages. Whether or not they bought the soap, the act of making the decision left them with less willpower, as measured afterward in a test of how long they could squeeze a hand grip. In the slightly more affluent villages, people’s willpower wasn’t affected significantly. Because they had more money, they didn’t have to spend as much effort weighing the merits of the soap versus, say, food or medicine.
Spears and other researchers argue that this sort of decision fatigue is a major — and hitherto ignored — factor in trapping people in poverty. Because their financial situation forces them to make so many trade-offs, they have less willpower to devote to school, work and other activities that might get them into the middle class. It’s hard to know exactly how important this factor is, but there’s no doubt that willpower is a special problem for poor people. Study after study has shown that low self-control correlates with low income as well as with a host of other problems, including poor achievement in school, divorce, crime, alcoholism and poor health. Lapses in self-control have led to the notion of the “undeserving poor” — epitomized by the image of the welfare mom using food stamps to buy junk food — but Spears urges sympathy for someone who makes decisions all day on a tight budget. In one study, he found that when the poor and the rich go shopping, the poor are much more likely to eat during the shopping trip. This might seem like confirmation of their weak character — after all, they could presumably save money and improve their nutrition by eating meals at home instead of buying ready-to-eat snacks like Cinnabons, which contribute to the higher rate of obesity among the poor. But if a trip to the supermarket induces more decision fatigue in the poor than in the rich — because each purchase requires more mental trade-offs — by the time they reach the cash register, they’ll have less willpower left to resist the Mars bars and Skittles. Not for nothing are these items called impulse purchases.
And this isn’t the only reason that sweet snacks are featured prominently at the cash register, just when shoppers are depleted after all their decisions in the aisles. With their willpower reduced, they’re more likely to yield to any kind of temptation, but they’re especially vulnerable to candy and soda and anything else offering a quick hit of sugar. While supermarkets figured this out a long time ago, only recently did researchers discover why.
The discovery was an accident resulting from a failed experiment at Baumeister’s lab. The researchers set out to test something called the Mardi Gras theory — the notion that you could build up willpower by first indulging yourself in pleasure, the way Mardi Gras feasters do just before the rigors of Lent. In place of a Fat Tuesday breakfast, the chefs in the lab at Florida State whipped up lusciously thick milkshakes for a group of subjects who were resting in between two laboratory tasks requiring willpower. Sure enough, the delicious shakes seemed to strengthen willpower by helping people perform better than expected on the next task. So far, so good. But the experiment also included a control group of people who were fed a tasteless concoction of low-fat dairy glop. It provided them with no pleasure, yet it produced similar improvements in self-control. The Mardi Gras theory looked wrong. Besides tragically removing an excuse for romping down the streets of New Orleans, the result was embarrassing for the researchers. Matthew Gailliot, the graduate student who ran the study, stood looking down at his shoes as he told Baumeister about the fiasco.
Baumeister tried to be optimistic. Maybe the study wasn’t a failure. Something had happened, after all. Even the tasteless glop had done the job, but how? If it wasn’t the pleasure, could it be the calories? At first the idea seemed a bit daft. For decades, psychologists had been studying performance on mental tasks without worrying much about the results being affected by dairy-product consumption. They liked to envision the human mind as a computer, focusing on the way it processed information. In their eagerness to chart the human equivalent of the computer’s chips and circuits, most psychologists neglected one mundane but essential part of the machine: the power supply. The brain, like the rest of the body, derived energy from glucose, the simple sugar manufactured from all kinds of foods. To establish cause and effect, researchers at Baumeister’s lab tried refueling the brain in a series of experiments involving lemonade mixed either with sugar or with a diet sweetener. The sugary lemonade provided a burst of glucose, the effects of which could be observed right away in the lab; the sugarless variety tasted quite similar without providing the same burst of glucose. Again and again, the sugar restored willpower, but the artificial sweetener had no effect. The glucose would at least mitigate the ego depletion and sometimes completely reverse it. The restored willpower improved people’s self-control as well as the quality of their decisions: they resisted irrational bias when making choices, and when asked to make financial decisions, they were more likely to choose the better long-term strategy instead of going for a quick payoff. The ego-depletion effect was even demonstrated with dogs in two studies by Holly Miller and Nathan DeWall at the University of Kentucky. After obeying sit and stay commands for 10 minutes, the dogs performed worse on self-control tests and were also more likely to make the dangerous decision to challenge another dog’s turf. But a dose of glucose restored their willpower.
Despite this series of findings, brain researchers still had some reservations about the glucose connection. Skeptics pointed out that the brain’s overall use of energy remains about the same regardless of what a person is doing, which doesn’t square easily with the notion of depleted energy affecting willpower. Among the skeptics was Todd Heatherton, who worked with Baumeister early in his career and eventually wound up at Dartmouth, where he became a pioneer of what is called social neuroscience: the study of links between brain processes and social behavior. He believed in ego depletion, but he didn’t see how this neural process could be caused simply by variations in glucose levels. To observe the process — and to see if it could be reversed by glucose — he and his colleagues recruited 45 female dieters and recorded images of their brains as they reacted to pictures of food. Next the dieters watched a comedy video while forcing themselves to suppress their laughter — a standard if cruel way to drain mental energy and induce ego depletion. Then they were again shown pictures of food, and the new round of brain scans revealed the effects of ego depletion: more activity in the nucleus accumbens, the brain’s reward center, and a corresponding decrease in the amygdala, which ordinarily helps control impulses. The food’s appeal registered more strongly while impulse control weakened — not a good combination for anyone on a diet. But suppose people in this ego-depleted state got a quick dose of glucose? What would a scan of their brains reveal?
The results of the experiment were announced in January, during Heatherton’s speech accepting the leadership of the Society for Personality and Social Psychology, the world’s largest group of social psychologists. In his presidential address at the annual meeting in San Antonio, Heatherton reported that administering glucose completely reversed the brain changes wrought by depletion — a finding, he said, that thoroughly surprised him. Heatherton’s results did much more than provide additional confirmation that glucose is a vital part of willpower; they helped solve the puzzle over how glucose could work without global changes in the brain’s total energy use. Apparently ego depletion causes activity to rise in some parts of the brain and to decline in others. Your brain does not stop working when glucose is low. It stops doing some things and starts doing others. It responds more strongly to immediate rewards and pays less attention to long-term prospects.
The discoveries about glucose help explain why dieting is a uniquely difficult test of self-control — and why even people with phenomenally strong willpower in the rest of their lives can have such a hard time losing weight. They start out the day with virtuous intentions, resisting croissants at breakfast and dessert at lunch, but each act of resistance further lowers their willpower. As their willpower weakens late in the day, they need to replenish it. But to resupply that energy, they need to give the body glucose. They’re trapped in a nutritional catch-22:
1. In order not to eat, a dieter needs willpower.
2. In order to have willpower, a dieter needs to eat.
As the body uses up glucose, it looks for a quick way to replenish the fuel, leading to a craving for sugar. After performing a lab task requiring self-control, people tend to eat more candy but not other kinds of snacks, like salty, fatty potato chips. The mere expectation of having to exert self-control makes people hunger for sweets. A similar effect helps explain why many women yearn for chocolate and other sugary treats just before menstruation: their bodies are seeking a quick replacement as glucose levels fluctuate. A sugar-filled snack or drink will provide a quick improvement in self-control (that’s why it’s convenient to use in experiments), but it’s just a temporary solution. The problem is that what we identify as sugar doesn’t help as much over the course of the day as the steadier supply of glucose we would get from eating proteins and other more nutritious foods.
The benefits of glucose were unmistakable in the study of the Israeli parole board. In midmorning, usually a little before 10:30, the parole board would take a break, and the judges would be served a sandwich and a piece of fruit. The prisoners who appeared just before the break had only about a 20 percent chance of getting parole, but the ones appearing right after had around a 65 percent chance. The odds dropped again as the morning wore on, and prisoners really didn’t want to appear just before lunch: the chance of getting parole at that time was only 10 percent. After lunch it soared up to 60 percent, but only briefly. Remember that Jewish Israeli prisoner who appeared at 3:10 p.m. and was denied parole from his sentence for assault? He had the misfortune of being the sixth case heard after lunch. But another Jewish Israeli prisoner serving the same sentence for the same crime was lucky enough to appear at 1:27 p.m., the first case after lunch, and he was rewarded with parole. It must have seemed to him like a fine example of the justice system at work, but it probably had more to do with the judge’s glucose levels.
It’s simple enough to imagine reforms for the parole board in Israel — like, say, restricting each judge’s shift to half a day, preferably in the morning, interspersed with frequent breaks for food and rest. But it’s not so obvious what to do with the decision fatigue affecting the rest of society. Even if we could all afford to work half-days, we would still end up depleting our willpower all day long, as Baumeister and his colleagues found when they went into the field in Würzburg in central Germany. The psychologists gave preprogrammed BlackBerrys to more than 200 people going about their daily routines for a week. The phones went off at random intervals, prompting the people to report whether they were currently experiencing some sort of desire or had recently felt a desire. The painstaking study, led by Wilhelm Hofmann, then at the University of Würzburg, collected more than 10,000 momentary reports from morning until midnight.
Desire turned out to be the norm, not the exception. Half the people were feeling some desire when their phones went off — to snack, to goof off, to express their true feelings to their bosses — and another quarter said they had felt a desire in the past half-hour. Many of these desires were ones that the men and women were trying to resist, and the more willpower people expended, the more likely they became to yield to the next temptation that came along. When faced with a new desire that produced some I-want-to-but-I-really-shouldn’t sort of inner conflict, they gave in more readily if they had already fended off earlier temptations, particularly if the new temptation came soon after a previously reported one.
The results suggested that people spend between three and four hours a day resisting desire. Put another way, if you tapped four or five people at any random moment of the day, one of them would be using willpower to resist a desire. The most commonly resisted desires in the phone study were the urges to eat and sleep, followed by the urge for leisure, like taking a break from work by doing a puzzle or playing a game instead of writing a memo. Sexual urges were next on the list of most-resisted desires, a little ahead of urges for other kinds of interactions, like checking Facebook. To ward off temptation, people reported using various strategies. The most popular was to look for a distraction or to undertake a new activity, although sometimes they tried suppressing it directly or simply toughing their way through it. Their success was decidedly mixed. They were pretty good at avoiding sleep, sex and the urge to spend money, but not so good at resisting the lure of television or the Web or the general temptation to relax instead of work.
We have no way of knowing how much our ancestors exercised self-control in the days before BlackBerrys and social psychologists, but it seems likely that many of them were under less ego-depleting strain. When there were fewer decisions, there was less decision fatigue. Today we feel overwhelmed because there are so many choices. Your body may have dutifully reported to work on time, but your mind can escape at any instant. A typical computer user looks at more than three dozen Web sites a day and gets fatigued by the continual decision making — whether to keep working on a project, check out TMZ, follow a link to YouTube or buy something on Amazon. You can do enough damage in a 10-minute online shopping spree to wreck your budget for the rest of the year.
The cumulative effect of these temptations and decisions isn’t intuitively obvious. Virtually no one has a gut-level sense of just how tiring it is to decide. Big decisions, small decisions, they all add up. Choosing what to have for breakfast, where to go on vacation, whom to hire, how much to spend — these all deplete willpower, and there’s no telltale symptom of when that willpower is low. It’s not like getting winded or hitting the wall during a marathon. Ego depletion manifests itself not as one feeling but rather as a propensity to experience everything more intensely. When the brain’s regulatory powers weaken, frustrations seem more irritating than usual. Impulses to eat, drink, spend and say stupid things feel more powerful (and alcohol causes self-control to decline further). Like those dogs in the experiment, ego-depleted humans become more likely to get into needless fights over turf. In making decisions, they take illogical shortcuts and tend to favor short-term gains and delayed costs. Like the depleted parole judges, they become inclined to take the safer, easier option even when that option hurts someone else.
“Good decision making is not a trait of the person, in the sense that it’s always there,” Baumeister says. “It’s a state that fluctuates.” His studies show that people with the best self-control are the ones who structure their lives so as to conserve willpower. They don’t schedule endless back-to-back meetings. They avoid temptations like all-you-can-eat buffets, and they establish habits that eliminate the mental effort of making choices. Instead of deciding every morning whether or not to force themselves to exercise, they set up regular appointments to work out with a friend. Instead of counting on willpower to remain robust all day, they conserve it so that it’s available for emergencies and important decisions.
“Even the wisest people won’t make good choices when they’re not rested and their glucose is low,” Baumeister points out. That’s why the truly wise don’t restructure the company at 4 p.m. They don’t make major commitments during the cocktail hour. And if a decision must be made late in the day, they know not to do it on an empty stomach. “The best decision makers,” Baumeister says, “are the ones who know when not to trust themselves.”
John Tierney (tierneylab@nytimes.com) is a science columnist for The Times. His essay is adapted from a book he wrote with Roy F. Baumeister, “Willpower: Rediscovering the Greatest Human Strength,” which comes out next month.
Wednesday, August 17, 2011
PAN African chimpanzee census, counting chimps and mapping culture
Apes in Africa: The cultured chimpanzees
by Gayathri Vaidyanathan
From NATURE NEWS
pdf can be downloaded here
Do chimpanzees have traditions? As wild populations dwindle, researchers are racing to find out.
Thump! Thump! Thump! As the hollow sound echoes through the Liberian rainforest, Vera Leinert and her fellow researchers freeze. Silently, Leinert directs the guide to investigate. Jefferson 'Bola' Skinnah, a ranger with the Liberian Forestry Development Authority, stalks ahead, using the thumping to mask the sound of his movement.
In a sunlit opening in the forest, Skinnah spots a large adult chimpanzee hammering something with a big stone. The chimpanzee puts a broken nut into its mouth then continues pounding. When Skinnah tries to move closer, the chimp disappears into the trees. By the time Leinert and her crew get to the clearing, the animal is long gone.
For the past year, Leinert has been trekking through Sapo National Park, Liberia's first and only protected reserve, to study its chimpanzee population. A student volunteer at the Max Planck Institute for Evolutionary Anthropology (EVA) in Leipzig, Germany, Leinert has never seen her elusive subjects in the flesh but she knows some of them well. There's an energetic young male with a big belly who hammers nuts so vigorously he has to grab a sapling for support. There are the stronger adults who can split a nut with three blows. And there are the mothers who parade through the site with their babies. They've all been caught by video cameras placed strategically throughout Sapo.
Chimpanzees in the wild are notoriously difficult to study because they flee from humans — with good reason. Bushmeat hunting and human respiratory diseases have decimated chimpanzee populations1, while logging and mining have wiped out their habitat. Population numbers have plunged — although no one knows by exactly how much because in most countries with great apes, the animals have never been properly surveyed.
The Pan Africa Great Ape Program, the first Africa-wide great-ape census to be mounted, could change that. In addition to surveying chimpanzee numbers (see 'How many chimpanzees are left?'), project scientists plan to set up automated video and audio recording devices at 40 research sites in 15 countries with chimp populations. Led by Christophe Boesch, director of the primatology department at the EVA, and Hjalmar Kühl, also at the EVA, the programme aims to get a picture of how chimpanzee behaviour — from nut cracking to vocal calls — varies across Africa. Ultimately, the hope is to learn about the origins and extent of what, in humans, would be called culture.
Until recently, scientists regarded culture — defined as socially transmitted behaviours — as exclusive to humans, but there is growing recognition that many animals exhibit some sort of culture. Chimpanzees, which share 98% of their genes with humans, have the most varied set of behaviours documented in the animal world. The difference between humans and animals is growing less distinct, say some researchers. "It is not black and white," says Kühl, who is Leinert's supervisor at the EVA.
In the old scenario, "only humans have culture", says Jason Kamilar, a biogeographer in the department of anthropology at Yale University in New Haven, Connecticut. "Then, culture would be the defining feature of humanity, which evolved some time after the split between the human and chimp lineages," he says. But "if chimps have culture, then presumably the last common ancestor of chimps and humans had culture".
Mapping Behaviour
Some chimps dance slowly at the beginning of rain showers, others don't; some use long sticks to dig up army ants; others use short sticks. In West Africa, some chimp groups hammer nuts with a stone or a piece of wood to open them. But east of the river Nzo-Sassandra, which cuts across Côte d'Ivoire, only one group has been seen cracking nuts.
So far, researchers have observed these variations over years spent studying groups of chimpanzee that have been carefully habituated to the presence of humans. There are just 12 such colonies in Africa (see 'Chimpanzee census'), the most famous of which is in Gombe Stream National Park in Tanzania, where primatologist Jane Goodall worked.
In 1999, evolutionary psychologist Andrew Whiten of the University of St Andrews, UK, and his colleagues compiled a list of behaviours seen in seven of those groups and showed that chimpanzees have unique traditions depending on where they live2. They identified at least 39 behaviours from a list of 65 that varied between groups for no obvious reason.
In humans, culture is passed on from one person to another, and in laboratory studies chimpanzees have shown the capacity to pass on learned customs. In one experiment, Whiten and his colleagues taught two chimps a complex series of steps for getting food from a box. Soon after the chimps were reunited with their groups, all the animals were using this method to get their food3. But whether such social learning happens in the wild is less clear. Gorillas and bonobos can also learn to use tools in the lab, but rarely use them in their natural habitat4.
Deciphering culture in the wild is difficult because researchers must ensure that behavioural differences between groups do not have other causes, such as variation in genetics or environmental conditions. "Why is it all chimps don't do everything? One solution is that there are hidden ecological differences between populations," says primatologist Richard Wrangham at Harvard University in Cambridge, Massachusetts. A behaviour could be linked to any number of variables such as amount of rainfall, the types of tree available, or the kinds of predator in the area, he says.
These influences can be subtle, as researchers found while studying how chimps use sticks to harvest army ants. Chimpanzees in Guinea sometimes use short sticks and sometimes use sticks up to twice as long. No reason for this was obvious until Tatyana Humle, an anthropologist at the University of Kent, UK, found that some ants are more aggressive, with longer legs and larger mandibles; they run up sticks quicker and bite harder5. This might explain why chimps elsewhere in Africa also choose tools of varying lengths to get at ants.
But researchers have not been able to find obvious explanations for other variations related to ant harvesting. Chimpanzees in Cote d'Ivoire sweep the ants off their sticks and into their palms before eating; in Guinea, only about 320 kilometres away, the animals stick the ant-laden sticks directly into their mouths. The same type of ant is present in both places.
Ruling out genetic influences is equally complicated. This year, molecular ecologist Kevin Langergraber at the EVA and his colleagues compared genetic and behavioural data for nine groups of chimpanzee. They found that communities with greater overlap in their mitochondrial DNA showed more similarities in their behaviour6. "What we are saying is, you haven't really ruled out the genetic explanation," says Langergraber.
There may be a few hundred thousand chimpanzees in Africa, but researchers have studied just 700–1,000 chimpanzees at the dozen sites with well habituated colonies, says Whiten. The available information from those groups is too little to determine how genes and the environment influence behavioural variations. Kühl compares the situation to using a handful of villages scattered around the world to draw basic conclusions about all the rituals that define human culture.
Whiten and his colleagues are now carrying out more detailed comparisons of the behaviour and ecology of chimps at all the habituated sites. But it has taken 50 years to capture the data they are using, most of which were recorded by painstaking observational studies.
The way forward may be the use of cameras hidden in strategic sites, like those Leinert and her team are setting up in Liberia. Such techniques have already proved their worth. Two years ago in Gabon, Boesch and his team were puzzled by random pits they observed in the ground. They set up camera traps and obtained video recordings of chimps digging to extract honey from underground bees' nests — something that had never been seen before7. "Camera traps are proving to be an exciting way to reveal new and often complex behavioural techniques in wild chimpanzee communities," says Whiten.
Caught in the act
At the site in Sapo, Leinert pulls on gloves to measure the rock used by the chimp to crack open nuts of the Guinea plum, Parinari excelsa. The rock is sizeable, weighing in at 880 grams. She collects nuts for later analysis, as well as hair and dung samples for genetic studies.
Leinert may later put up a video camera at the location to collect more data on the nut-cracking behaviour. The cameras are mounted in boxes on tree trunks at the height of a chimp's shoulder, and powered by rechargeable batteries. An infrared motion detector activates the camera for one minute when anything moves in its range.
Near the nut-cracking site, a solar-powered audio device is already continuously recording the forest sounds. Chimpanzees emit a range of calls, including short, high-pitched 'pant hoots' that are unique to each individual, and researchers can use them to identify individuals and to tally the size of a community. These calls may be a form of vocal culture, somewhat like human dialects8.
Over the next five years, the Pan Africa Great Ape Program will establish similar recording stations at locations across Africa. "So potentially we might have, in a few years, behavioural differences from 40 different populations, which is, as you know, four times more than what we have now," says Boesch.
Kühl proposes that these data could help in designing computer models to test how genes, ecology and social transmission influence the distribution and spread of behaviours such as nut cracking. One idea is that when female chimpanzees reach sexual maturity and move to new communities, they pass along their learned behaviours. Another possibility is that each group invents its own behaviours, some of which catch on and become a culture. Individual practices can die out in particular groups but thrive in others. Or, it might be that some chimp groups refuse to take up new ways of doing things from incoming individuals. This could explain why some populations show similar behaviours and others do not.
Before Kühl and his colleagues can conduct the modelling work, they need to devise a faster way to go through the recordings made by the camera and audio traps, which are accumulating at a rate of hundreds of hours each month. Students are currently carrying out the analysis but it can take 10 hours to go through an hour of video, according to Kühl. So engineers at the Fraunhofer Institute for Digital Media Technology, based in Ilmenau, Germany, have developed a computer algorithm to recognize individual chimpanzees from their facial patterns and distinctive features, such as the wrinkles under their eyes. In tests of zoo animals, the software can correctly identify individual chimpanzees 83% of the time, and it processes recordings ten times faster than a person can.
Nevertheless, the cameras cannot reveal how an adult chimp patrols its range, or other actions that play out over a wide area. The full portfolio of traditions in the community will remain a mystery. And automated recordings will never capture the subtle ecological information — such as the mandible size and leg length of army ants — that may eventually explain particular behaviours. These require boots on the ground, and long-term behavioural studies are needed to see how chimpanzees pass traditions on to each other as a driver of culture.
But already, the 30 cameras that Leinert has set up in Sapo Park have delivered some tantalizing clues. She is most interested in the lively young male she calls 'Janosch', whom she likes for "his big belly and the way he strikes out to crack the nuts". Besides being entertaining, he sometimes carries his pounding rock away with him, something Leinert hasn't seen with most other chimpanzees in Sapo. The practice may yet catch on with others there. If so, Leinert could be seeing the beginnings of a cultural variation, captured by the cameras she set up in the forest.
--
Box: How many chimpanzees are left?
Jacob the chimp, now two years old, spends most of his day in a wooden box not much bigger than himself. Born in Sapo National Park in Liberia, he was rescued by a forest ranger, who found Jacob and his dead mother in the arms of a poacher.
Such tales are common in Africa. Bushmeat is a vital source of protein and a dead chimpanzee can fetch US$200 in Nigeria. No one knows exactly how many chimps there are in the wild: in 2003, the International Union for Conservation of Nature made a very rough estimate of 172,700–299,700. But the population is declining rapidly, and many communities are likely to disappear in the next few decades. A study in 2008 found that the population in Côte d'Ivoire had decreased by 90% in 17 years.
In 2010, the dearth of data prompted the Max Planck Institute for Evolutionary Anthropology (EVA) in Leipzig, Germany, to team up with the Wild Chimpanzee Foundation, headquartered at the EVA, and Conservation International, based in Arlington, Virginia, to launch the Pan Africa Great Ape Program. They aim to conduct nationwide surveys in 15 countries to estimate how many chimps are left in Africa. The scientists involved would not disclose the project's budget, but acknowledged that the surveys will be expensive and that they do not yet have all the necessary funding.
As part of the survey, graduate student Jessica Junker of the EVA and her Liberian team of graduate students and rangers from the Forest Development Authority are walking some 400 kilometres to survey 68 squares laid out on a grid across the country. They trek through uncut bush and overgrown farms, across rivers, and into deep muddy valleys to look for chimpanzee nests. Each chimp usually builds a new nest every day, and the researchers can estimate the age of a nest from its state of decomposition. They can then extrapolate to get an idea of the number of animals in an area. Their findings so far suggest that Liberia holds at least 3,300 chimpanzees.
Using similar methods in Sierra Leone, the 2008–10 Tacugama National Chimpanzee Census estimated that more than 5,500 chimpanzees live in that country. This is much higher than a 1981 estimate of 2,500, probably because the earlier survey used less systematic survey methods.
Christophe Boesch of the EVA, who co-heads the Pan Africa Great Ape Program, says that it will guide conservation efforts to where they can do the most good. But getting precise numbers on the great apes in each country is expensive because of the labour involved, and some conservationists would rather see the money spent on enforcing laws against poaching.
“We don't need a nationwide survey to tell us we are losing the battle,” says David Greer, who coordinates the African Great Apes Program for the conservation group WWF. “We need to be more assertive, more aggressive with intervention measures, trying to stop the decline.”
Planet of the Apes: Trophies painting
a little something disturbing for hump day (warning: some may find this offensive) via neatorama from http://www.etsy.com/listing/79751820/planet-of-the-apes-trophies-13-x-19
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Movies,
NOT science,
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teehee
Tuesday, August 16, 2011
Miss USA 2011 — Should Math Be Taught In Schools?
thanks to Amy C for the link (its a fabulous parody of this:
Monday, August 15, 2011
Sunday, August 14, 2011
baboon adopts bush baby at kenyan sanctuary
I think there are some obvious issues one could take with the story. but the whole thing is rather charming. -MA
Thursday, August 11, 2011
Tuesday, August 9, 2011
Gap between field and lab observations of chimps narrowing: chimps share.
Thanks to Geraldine F for the link!
From NYTimes
Chimpanzees Clear Some Doubt After Generosity Is Questioned
By CARL ZIMMER
When it comes to the evolution of humans, a lot depended on the kindness of strangers.
Our species is especially cooperative. We routinely help other people — relatives and strangers alike — even when there’s no immediate reward for us. The concern that humans have for each other is part of the foundation of complex societies, from neighborhoods to nations.
Scientists have long wondered how long ago our so-called prosocial behavior evolved. In a new paper published this week in the Proceedings of the National Academy of Sciences, a team of scientists at Emory University addresses that question with a study on chimpanzees, one of our closest living relatives. Contrary to some earlier laboratory tests, the Emory researchers concluded that chimpanzees are indeed willing to do favors for others. Our prosocial behavior may therefore date back at least several million years.
“These new results suggest chimpanzees may help others proactively simply because they understand they need help,” said Brian Hare, an anthropologist at Duke University.
The Emory researchers decided to undertake the study because of a contradiction in the scientific literature. Some lab experiments on chimpanzees failed to show a willingness to help, but primatologists who observed chimpanzees in the wild saw many examples of what looked like helping. “They’re sharing food, they’re helping each other in fights — there was a huge mismatch between what was going on in the field and in the lab,” said Victoria Horner, the lead author of the study.
Dr. Horner and her colleagues suspected that the design of earlier lab studies had been too complex for the chimpanzees to figure out. “It seemed to us that the chimps didn’t understand what was going on,” said Dr. Horner.
They set up what they believed was a much simpler experiment. For an earlier study, they had trained captive chimpanzees to give them colored tokens in exchange for food. For the current study, they used those tokens to give seven female chimpanzees a chance to help out fellow chimps.
In each trial a pair of chimpanzees sat next to each other, able to see each other in adjoining cages. They were given 30 tokens, half in one color and half in another. If a chimp gave the scientists a token of one color, she got a package of food while her partner got none. If she gave the other color, both of them got something to eat.
If chimpanzees didn’t care about the welfare of other chimpanzees, the scientists predicted, they’d pick both colors equally often. That’s not what happened. All of the chimpanzees were more likely to pick the generous color, up to 66.7 percent of the time. They showed no preference for their relatives versus unrelated chimps. The scientists also ran control sessions, in which the chimpanzees got food only for themselves, no matter which color they chose. In these control sessions, they had no bias in their choice of colors.
“This now fits with the evidence we know from the wild,” Dr. Horner said.
She speculates that human helping evolved from the kind of bias she and her colleagues see in chimpanzees, as the probability of helping rose in our ancestors. “It’s not that we have a unique ability, but it’s the number of instances of when we do it is vastly different,” she said.
Several experts gave Dr. Horner and her colleagues high marks. “They have been able for the first time to duplicate what field researchers already knew was a natural ability of chimpanzees,” said Christophe Boesch, a primatologist at the Max Planck Institute for Evolutionary Anthropology in Germany.
But Michael Tomasello, also at the Max Planck Institute, found the study poorly designed. “The results are uninterpretable,” he said. He notes that the Emory scientists ran their control sessions after the experimental sessions. “Maybe the chimpanzees were just tired of choosing the two-pieces-of-food option by the time the control conditions were run,” Dr. Tomasello said.
Dr. Tomasello and his colleagues have published their own experiments on prosocial behavior in chimps, most recently in July in the journal Nature. His own research leads Dr. Tomasello to a somewhat different conclusion from Dr. Horner’s. “Chimps help others, but what they do not do is give up food themselves so others can have it,” he said. “So they are prosocial when it is not costly, but when it is, not so much.”
Sunday, August 7, 2011
Sexually showy birds age faster
Thanks to Kate M for the link!
By Victoria Gill
The flamboyant "booming" display of the threatened Houbara bustard is linked to the rate at which the birds age
A large, flamboyant bird has given biologists an insight into the relationship between sex and ageing.
The male Houbara bustard has striking ornamental feathers that it displays while running around and "booming" to attract a mate.
As scientists report in Ecology Letters, birds that indulge in more of these sexual displays age faster.
The more "showy" males experienced earlier age-related declines in the quality of their sperm.
The team used 10-years-worth of data on the sexual behaviour and fertility of more than 1,700 North African Houbara bustards that were bred by conservationists in Missour, Morocco.
"The birds are a threatened species, and the data was collected as part of an ongoing conservation programme aimed at increasing their numbers in the wild," explained lead researcher Brian Preston, a scientist based at the University of Burgundy, France.
The scientists measured how much time each male spent carrying out its elaborate display, and compared this to changes in its fertility that are associated with ageing.
By examining the birds' sperm, the researchers discovered that all males experienced a "dramatic decline" in their fertility as they aged.
"Over the age of six years," said Dr Preston. "They began to produce much smaller ejaculates with immobile and frequently abnormal sperm."
"But the key finding was that males that had invested most effort displaying to females in their earlier years experienced the onset of this age-related decline in fertility at a younger age.
"They effectively seem to 'burn themselves out' sooner."
Evolutionary puzzle
Bustards are particularly interesting to scientists trying to understand the biology of ageing, because they are such long-lived birds. The male bustards studied here were between one and 24 years of age.
The male bustards display for up to 18 hours a day, for six months of the year
"We might expect that genes that would cause animal to deteriorate with age would be 'weeded out' by natural selection," said Dr Preston. "So it's something of a problem for evolutionary biologists."
One of the theories to explain this evolutionary anomaly is that animals might "overspend" on activities in their early life, by, for example, expending lots of energy on gaudy sexual displays. This might be at the cost of maintaining their body properly in the longer term.
"This is precisely the kind of relationship we have found," said Dr Preston.
"Life is risky," he continued. "Predators, parasites and diseases are likely to prevent animals from living for long periods anyway. So it might be better for them to spend now and not worry about later."
John Burnside, a zoologist from the University of Bath said the findings were "very interesting".
"These results show what may be a classic trade-off - that males invest more in breeding displays when they are young lose sperm viability when they're older," he told BBC Nature.
Studies like this, he added, help "fill in the jigsaw of the complex feedback systems that can occur during natural selection".
--
Reference
Abstract
Evolutionary theories of ageing posit that increased reproductive investment occurs at the expense of physiological declines in later life. Males typically invest heavily in costly sexual ornaments and behaviour, but evidence that the expression of these traits can cause senescence is lacking. Long-lived houbara bustards (Chlamydotis undulata) engage in extravagant sexual displays to attract mates and here we show that males investing most in these displays experience a rapid senescent deterioration of spermatogenic function at a younger age. This effect is sufficiently large that the expected links between male ‘showiness’ and fertility reverse in later life, despite ‘showy’ males continuing to display at near maximal levels. We show that our results cannot be explained by the selective disappearance of competitive phenotypes and that they are instead consistent with an early vs. late life trade-off in male reproductive competence, highlighting the potential significance of sexual selection in explaining rates of ageing.
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