The tendency to perceive others as "us versus them" isn't exclusively human but appears to be shared by our primate cousins, a new study led by Yale researchers has found.
In a series of ingenious experiments, Yale researchers led by psychologist Laurie Santos showed that monkeys treat individuals from outside their groups with the same suspicion and dislike as their human cousins tend to treat outsiders, suggesting that the roots of human intergroup conflict may be evolutionarily quite ancient.
The findings are reported in the March issue of the Journal of Personality and Social Psychology.
"One of the more troubling aspects of human nature is that we evaluate people differently depending on whether they're a member of our 'ingroup' or 'outgroup,'" Santos said. "Pretty much every conflict in human history has involved people making distinctions on the basis of who is a member of their own race, religion, social class, and so on. The question we were interested in is: Where do these types of group distinctions come from?"
The answer, she adds, is that such biases have apparently been shaped by 25 million years of evolution and not just by human culture.
Santos and her lab studied the rhesus macaques living on an island off the coast of Puerto Rico. Like humans, monkeys in this population naturally form different social groups on the basis of family history. In order to assess whether monkeys made the same distinctions between ingroup and outgroup individuals, the researchers used a well-known tendency of animals to stare longer at novel or frightening things than at familiar or friendly things. They presented subject monkeys with pictures of monkeys who were either in their social group or members of a different group. They found that monkeys stared longer at pictures of other monkeys who were outside their group, suggesting that monkeys spontaneously detect who is a stranger and who is a group member.
"What made this result even more remarkable" noted Neha Mahajan, a Yale graduate student who headed up this project, "is that monkeys in this population move around from group to group, so some of the monkeys who were 'outgroup' were previously 'ingroup.' And yet, the result holds just as strongly for monkeys who have transferred groups only weeks earlier, suggesting that these monkeys are sensitive to who is currently to be thought of as an insider or an outsider. In other words, although monkeys divide the world into 'us' versus 'them,' they do so in a way that is flexible and is updated in real time."
Santos and colleagues then asked whether monkeys evaluated ingroup and outgroup members differently -- did they associate these individuals automatically with "good" and "bad" respectively? To study this, they developed a monkey version of a test of implicit attitudes known as the IAT. In humans, this test measures the extent to which people show implicit biases against members of other groups. To look at the same capacity in monkeys, the researchers showed monkeys a sequence of photos in which photos of ingroup or outgroup monkey faces were paired with photos of either good things, such as fruits, or bad things, such as spiders.
The researchers then recorded the time monkeys spent looking at both kinds of sequences. The monkeys spent little time looking at sequences that included ingroup faces paired with good stuff like fruits or outgroup faces paired with bad stuff like spiders, suggesting that the monkeys treated these two kinds of stimuli as being similar. On the other hand, the monkeys stared longer at sequences in which outgroup individuals were paired with positive objects like fruit suggesting that this association was unnatural to the monkeys. Like humans, monkeys tend to spontaneously view ingroup members positively and outgroup members negatively.
The Yale team's results suggest that the distinctions humans make between "us" and "them" -- and therefore the roots of human prejudice -- may date back at least 25 million years, when humans and rhesus macaques shared a common ancestor.
"Social psychologists introduced the world to the idea that the immediate situation is hugely powerful in determining behavior, even intergroup feelings," said Mahzarin Banaji, of the Department of Psychology at Harvard University and a co-author of the paper. "Evolutionary theorists have made us aware of our ancestral past. In this work, we weave the two together to show the importance of both of these influences at work."
"The bad news is that the tendency to dislike outgroup members appears to be evolutionarily quite old, and therefore may be less simple to eliminate than we'd like to think," Santos said. "The good news, though, is that even monkeys seem to be flexible about who counts as a group member. If we humans can find ways to harness this evolved flexibility, it might allow us to become an even more tolerant species."
Other Yale authors of the paper are Margaret A. Martinez and Natashya Gutierrez. Researchers from Bar-Ilan University and Harvard also contributed to the study.
The work was funded the National Center for Research Resources, part of the National Institutes of Health.
______________
References:
Science Daily. 2011. "Human Prejudice Has Ancient Evolutionary Roots". Science Daily. Posted: March 18, 2011. Available online: http://www.sciencedaily.com/releases/2011/03/110317102552.htm
Journal Reference:
Neha Mahajan, Margaret A. Martinez, Natashya L. Gutierrez, Gil Diesendruck, Mahzarin R. Banaji, Laurie R. Santos. The evolution of intergroup bias: Perceptions and attitudes in rhesus macaques.. Journal of Personality and Social Psychology, 2011; 100 (3): 387 DOI: 10.1037/a0022459
Showing posts with label primatology. Show all posts
Showing posts with label primatology. Show all posts
Monday, March 28, 2011
Monday, March 14, 2011
Gibbon songs have regional accents, says new study
Call of the wild has different accents
Washingtonians who live close to the National Zoo know all too well about gibbon songs. The small apes begin calling out to one another every morning at dawn and again throughout the day whenever they switch locations, get a lot of visitors or just feel like hollering.
It turns out that some of those songs might have distinctive characteristics similar to accents, according to a recent study in the journal BMC Evolutionary Biology.
Washingtonians who live close to the National Zoo know all too well about gibbon songs. The small apes begin calling out to one another every morning at dawn and again throughout the day whenever they switch locations, get a lot of visitors or just feel like hollering.
It turns out that some of those songs might have distinctive characteristics similar to accents, according to a recent study in the journal BMC Evolutionary Biology.
After analyzing samples from more than 400 gibbon songs, researchers at the German Primate Center in Goettingen found that the calls can be used to identify which species of gibbon is singing as well as the area it's from. The scientists were able to distinguish the sounds of apes from various parts of the dense rain forests of Cambodia, Vietnam and Laos, where gibbons live in the wild.
However, people living near the zoo won't be able to detect the regional differences without sophisticated sound analysis software; not even Lisa Stevens can do that, and she's been working with the zoo's gibbons for 33 years. Stevens, the zoo's curator of primates, says the songs of the six gibbons living there are very similar. The zoo has four white-cheeked gibbons: two males that were born there and two females that were brought in from the wild, probably from Vietnam. The females are "geriatric" now at ages 41 and 43, Stevens says. They came to the United States in the late 1960s or early 1970s from markets in Southeast Asia where people were selling them as pets.
The zoo also has two siamangs from the Malay peninsula.
Stevens was not surprised at the study's results, because regional variation in color and pattern of gibbon coats has already been established. She expects that there are also behavioral differences among gibbons from different regions. Gibbons sing to define their territory and to find mates, but Stevens suspects there's more content than that. "We're just scratching the surface of the information that they're communicating in gibbon calls," she said.
____________
References:
Saslow, Rachel. 2011. "Gibbon songs have regional accents, says new study". Washington Post. Posted: February 28, 2011. Available online: http://www.washingtonpost.com/wp-dyn/content/article/2011/02/28/AR2011022805262.html
Picture: Mehgan Murphy / National Zoo
Saturday, December 4, 2010
50 Years of Chimpanzees
Jane Goodall went to the Gombe Stream Reserve near Lake Tanganyika in East Africa when she was 26. By living among the animals and quietly recording their interactions, she was able to show that the chimp world included love, hate, fear, jealousy, tool use, brutality, even warfare. I spoke with Dr. Goodall last month at Western Connecticut State College, where she was giving a lecture, and then later by telephone. A condensed version of the conversations follows:
Q. In July you celebrated the 50th anniversary of your first trip to Gombe Stream Reserve. When you arrived there in 1960, could you have imagined the life that lay ahead?
A. Of course not. I was a young girl, straight from England, more or less, no degree of any sort, and Louis Leakey was giving me this amazing opportunity to live with the animal most like us.
There’d been no long-term studies of great apes. The longest had been George Schaller, with mountain gorillas, and he’d stayed a year. I think Louis Leakey thought the study might last 10 years. But at 26, I thought perhaps three. And then the more I learned about chimpanzees, the more I realized there was more to learn — until I couldn’t stop.
Q. So you got to Gombe, and very soon, you observed something astounding: Chimpanzees used tools to fish for ants.
A. I went in July. And tool-making was toward the end of October.
Q. After you had lived with the wild chimpanzees for a year, Dr. Leakey sent you to Cambridge for a doctorate. How did the conservative professors there respond to you?
A. They didn’t know what to make of me. But I was very fortunate in that I had one of the most erudite of all the animal behavior people, Robert Hinde, there. He proceeded to help me to write in such a way that I couldn’t be torn apart by my more pompous scientific colleagues.
For instance, I had written that when Fifi’s (one of the Gombe chimps) brother was born, she was jealous of the others coming to try to touch him. Robert said, “You can’t say ‘jealous’ because you can’t prove it.” And I said, “Well, I’m sure she was!” And he said, “I suggest you say, ‘Fifi behaved in such a way that had she been a human child, you would say she was jealous.’ ” That is so clever. No one can say anything about that. There’s nothing that isn’t fact.
Q. When you first reported chimp tool use, Dr. Leakey declared, "We must now redefine man, redefine tool or accept chimpanzees as human!" Did that ever happen?
A. It’s never happened. Every time someone has shown that chimpanzees or any other animal possesses a characteristic which we used to think was unique to us, there’s an outcry from either scientists or religious people: “It can’t be so.”
It becomes illogical. For a long time people used chimpanzees in medical research because of all the amazing biological similarities. They used them to investigate not only human diseases but mental conditions like depression. Yet, they are still reluctant to admit similarities in mind and expressive emotion.
Q. There are 185 captive chimpanzees at the federal primate facility in Alamogordo, N.M., that may soon be used for medical research, particularly to study Hepatitis C. Why have you been trying to stop that?
A. Because it’s morally wrong. We scientists have proved pretty conclusively that chimpanzees can suffer, that they can anticipate arriving pain. They do have feelings. If you perform an invasive procedure on an animal that is capable of suffering and feeling pain, your behavior is amoral.
These particular animals have been “retired” from experimentation for the past 10 years. Now suddenly someone has decided that they need to experiment on them again. I don’t know why. We’re lobbying. I’ve tried to see the head of the N.I.H. My latest information is that some of them have already gone back into medical research — and this was just as the labs (that use chimps as research subjects) were being closed.
Q. The advocates of this policy argue that short of using humans for these tests, chimpanzees are best.
A. I’m sure there are other ways. There are alternatives on the market today that at one time the animal experimenters said we will always need animals for.
Q. On a different subject: There's continuing debate among linguists and primatologists about whether other great apes have the capacity for language. What's your position?
A. It seems to me that the controversy is about whether other primates have grammar in their communications. And to be honest, I’m not interested in whether or not they have a grammar. Why would they? I’ve always felt there are so many fights in this life, so many battles that seem important to win. Like in the beginning I was incensed to be told that chimpanzees or any animal couldn’t be “he” or “she,” but they had to be an “it” and that I couldn’t talk about adolescence or motivation or childhood, that those things are unique to humans. This language thing, I’d rather leave it to people who are involved in that line of inquiry. I’ve been fighting battles that, to me, were important, and that relate to emotions. Do they feel pain or sadness? Do they have minds capable of thinking or planning?
Q. I read somewhere that before you went to Africa, you were a debutante. Can that be true?
A. I was. My father’s sister married the son of one of the last lord chief justices of India. And he wanted to “present” his niece. But the thing about being a debutante is that it’s a marriage market. When you come out, you have a big party and you go to Ascot. Well, we couldn’t afford anything like that. So I got a dress that had been modeled by someone. It was very cheap — gorgeous, but cheap. I literally went to the palace and curtsied to the queen and left. This was about two years before I left for Kenya. That kind of life was never, in the remotest, appealing. I wanted to go to Africa. Because of Dr. Dolittle taking the circus animals back. And then Tarzan. Those were the two books that inspired me to go to Africa.
Q. Are there areas of your life that you regret?
A. Not really. Probably for my own personal peace of mind, it would have been nice if I hadn’t divorced Hugo (van Lawick), my first husband, for the sake of Grub (their son). But then I wouldn’t have married Derek (Bryceson, the head of the Tanzanian National Parks), and then probably Gombe would have collapsed.
Q. You don't get to Gombe very often now. In fact, you are traveling 300 days a year for your conservation charity, the Jane Goodall Institute. Living in a different hotel every night, constantly encountering new people: that has to be difficult.
A. Well, it is a jolly tough way to live, but it’s worthwhile. Because everywhere I go, there are shining eyes. There are children from our Roots and Shoots program who are all so excited to meet “Dr. Jane” and tell me what they’ve been doing to make the world a better place.
There’s a Roots and Shoots member in the Eastern Congo — where the bush meat trade is decimating wildlife — and he had an uncle who was a hunter. He persuaded the uncle to give it up and become a chicken farmer. Between them, in two years, they’ve changed 75 hunters. When I meet people like that, they give me energy and hope.
_______________
References:
Dreifus, Claudia. 2010. "50 Years of Chimpanzees". The New York Times. Posted: November 15, 2010. Available online: http://www.nytimes.com/2010/11/16/science/16conversation.html?_r=1
Q. In July you celebrated the 50th anniversary of your first trip to Gombe Stream Reserve. When you arrived there in 1960, could you have imagined the life that lay ahead?
A. Of course not. I was a young girl, straight from England, more or less, no degree of any sort, and Louis Leakey was giving me this amazing opportunity to live with the animal most like us.
There’d been no long-term studies of great apes. The longest had been George Schaller, with mountain gorillas, and he’d stayed a year. I think Louis Leakey thought the study might last 10 years. But at 26, I thought perhaps three. And then the more I learned about chimpanzees, the more I realized there was more to learn — until I couldn’t stop.
Q. So you got to Gombe, and very soon, you observed something astounding: Chimpanzees used tools to fish for ants.
A. I went in July. And tool-making was toward the end of October.
Q. After you had lived with the wild chimpanzees for a year, Dr. Leakey sent you to Cambridge for a doctorate. How did the conservative professors there respond to you?
A. They didn’t know what to make of me. But I was very fortunate in that I had one of the most erudite of all the animal behavior people, Robert Hinde, there. He proceeded to help me to write in such a way that I couldn’t be torn apart by my more pompous scientific colleagues.
For instance, I had written that when Fifi’s (one of the Gombe chimps) brother was born, she was jealous of the others coming to try to touch him. Robert said, “You can’t say ‘jealous’ because you can’t prove it.” And I said, “Well, I’m sure she was!” And he said, “I suggest you say, ‘Fifi behaved in such a way that had she been a human child, you would say she was jealous.’ ” That is so clever. No one can say anything about that. There’s nothing that isn’t fact.
Q. When you first reported chimp tool use, Dr. Leakey declared, "We must now redefine man, redefine tool or accept chimpanzees as human!" Did that ever happen?
A. It’s never happened. Every time someone has shown that chimpanzees or any other animal possesses a characteristic which we used to think was unique to us, there’s an outcry from either scientists or religious people: “It can’t be so.”
It becomes illogical. For a long time people used chimpanzees in medical research because of all the amazing biological similarities. They used them to investigate not only human diseases but mental conditions like depression. Yet, they are still reluctant to admit similarities in mind and expressive emotion.
Q. There are 185 captive chimpanzees at the federal primate facility in Alamogordo, N.M., that may soon be used for medical research, particularly to study Hepatitis C. Why have you been trying to stop that?
A. Because it’s morally wrong. We scientists have proved pretty conclusively that chimpanzees can suffer, that they can anticipate arriving pain. They do have feelings. If you perform an invasive procedure on an animal that is capable of suffering and feeling pain, your behavior is amoral.
These particular animals have been “retired” from experimentation for the past 10 years. Now suddenly someone has decided that they need to experiment on them again. I don’t know why. We’re lobbying. I’ve tried to see the head of the N.I.H. My latest information is that some of them have already gone back into medical research — and this was just as the labs (that use chimps as research subjects) were being closed.
Q. The advocates of this policy argue that short of using humans for these tests, chimpanzees are best.
A. I’m sure there are other ways. There are alternatives on the market today that at one time the animal experimenters said we will always need animals for.
Q. On a different subject: There's continuing debate among linguists and primatologists about whether other great apes have the capacity for language. What's your position?
A. It seems to me that the controversy is about whether other primates have grammar in their communications. And to be honest, I’m not interested in whether or not they have a grammar. Why would they? I’ve always felt there are so many fights in this life, so many battles that seem important to win. Like in the beginning I was incensed to be told that chimpanzees or any animal couldn’t be “he” or “she,” but they had to be an “it” and that I couldn’t talk about adolescence or motivation or childhood, that those things are unique to humans. This language thing, I’d rather leave it to people who are involved in that line of inquiry. I’ve been fighting battles that, to me, were important, and that relate to emotions. Do they feel pain or sadness? Do they have minds capable of thinking or planning?
Q. I read somewhere that before you went to Africa, you were a debutante. Can that be true?
A. I was. My father’s sister married the son of one of the last lord chief justices of India. And he wanted to “present” his niece. But the thing about being a debutante is that it’s a marriage market. When you come out, you have a big party and you go to Ascot. Well, we couldn’t afford anything like that. So I got a dress that had been modeled by someone. It was very cheap — gorgeous, but cheap. I literally went to the palace and curtsied to the queen and left. This was about two years before I left for Kenya. That kind of life was never, in the remotest, appealing. I wanted to go to Africa. Because of Dr. Dolittle taking the circus animals back. And then Tarzan. Those were the two books that inspired me to go to Africa.
Q. Are there areas of your life that you regret?
A. Not really. Probably for my own personal peace of mind, it would have been nice if I hadn’t divorced Hugo (van Lawick), my first husband, for the sake of Grub (their son). But then I wouldn’t have married Derek (Bryceson, the head of the Tanzanian National Parks), and then probably Gombe would have collapsed.
Q. You don't get to Gombe very often now. In fact, you are traveling 300 days a year for your conservation charity, the Jane Goodall Institute. Living in a different hotel every night, constantly encountering new people: that has to be difficult.
A. Well, it is a jolly tough way to live, but it’s worthwhile. Because everywhere I go, there are shining eyes. There are children from our Roots and Shoots program who are all so excited to meet “Dr. Jane” and tell me what they’ve been doing to make the world a better place.
There’s a Roots and Shoots member in the Eastern Congo — where the bush meat trade is decimating wildlife — and he had an uncle who was a hunter. He persuaded the uncle to give it up and become a chicken farmer. Between them, in two years, they’ve changed 75 hunters. When I meet people like that, they give me energy and hope.
_______________
References:
Dreifus, Claudia. 2010. "50 Years of Chimpanzees". The New York Times. Posted: November 15, 2010. Available online: http://www.nytimes.com/2010/11/16/science/16conversation.html?_r=1
Thursday, July 22, 2010
"Extinct," Pop-Eyed Primate Photographed for First Time
Fewer than a hundred Horton Plains slender lorises thought to survive.
Long thought to be extinct, one of the world's rarest primates has been caught on camera for the first time, scientists announced Monday.
Discovered in 1937 but "missing" for 60 years, Sri Lanka's Horton Plains slender loris was presumed to have died out. In 2002 a fleeting nighttime sighting of something looking like the elusive tree-dweller, however, gave conservationists hope.
Follow-up surveys led by the Zoological Society of London finally confirmed the lorises are alive—if not exactly well—in 2009, when two individuals were photographed and examined.
Initial estimates after the rediscovery put the total world population at fewer than a hundred, said the society's conservation biologist Craig Turner. And in this case, the world is limited to high cloud forests in the Horton Plains area (map) of central Sri Lanka—the animal's only known habitat.
"Potentially this is the rarest primate we're aware of today," Turner said.
Lonely Lorises
About 8 inches (20 centimeters) long and weighing just 11 ounces (310 grams), the slow-moving loris has been doomed as forests have been felled for firewood and to make way for tea plantations and other farms, Turner said.
"There's no means for these lorises to move between the [remaining] forest patches," Turner said. "In terms of breeding and finding mates, it is very difficult for them." (See a satellite picture of Horton Plains' forests.)
"The real focus now has to be on the remaining forest areas and looking at how we can enhance and protect them, and also reconnect them to one another," he added.
"New" Loris Also New Species?
The Horton Plains slender loris is generally classified as a subspecies of Sri Lanka's red slender loris. But, thanks in part to the first ever pictures, researchers now believe the "extinct" loris could be a whole new species.
"It's clearly very different physically," Turner said. Compared to lowland lorises, the Horton Plains loris is "stockier, shorter limbed—and it's got a much longer fur coat."
Ongoing tests on DNA samples taken from the few individuals recorded to date, he added, should help to settle the issue.
__________________
References:
Owen, James. 2010. ""Extinct," Pop-Eyed Primate Photographed for First Time". National Geographic News. Posted: July 19, 2010. Available online: http://news.nationalgeographic.com/news/2010/07/100719-horton-plains-slender-loris-pictures-first-time-science/
Long thought to be extinct, one of the world's rarest primates has been caught on camera for the first time, scientists announced Monday.
Discovered in 1937 but "missing" for 60 years, Sri Lanka's Horton Plains slender loris was presumed to have died out. In 2002 a fleeting nighttime sighting of something looking like the elusive tree-dweller, however, gave conservationists hope.
Follow-up surveys led by the Zoological Society of London finally confirmed the lorises are alive—if not exactly well—in 2009, when two individuals were photographed and examined.
Initial estimates after the rediscovery put the total world population at fewer than a hundred, said the society's conservation biologist Craig Turner. And in this case, the world is limited to high cloud forests in the Horton Plains area (map) of central Sri Lanka—the animal's only known habitat.
"Potentially this is the rarest primate we're aware of today," Turner said.
Lonely Lorises
About 8 inches (20 centimeters) long and weighing just 11 ounces (310 grams), the slow-moving loris has been doomed as forests have been felled for firewood and to make way for tea plantations and other farms, Turner said.
"There's no means for these lorises to move between the [remaining] forest patches," Turner said. "In terms of breeding and finding mates, it is very difficult for them." (See a satellite picture of Horton Plains' forests.)
"The real focus now has to be on the remaining forest areas and looking at how we can enhance and protect them, and also reconnect them to one another," he added.
"New" Loris Also New Species?
The Horton Plains slender loris is generally classified as a subspecies of Sri Lanka's red slender loris. But, thanks in part to the first ever pictures, researchers now believe the "extinct" loris could be a whole new species.
"It's clearly very different physically," Turner said. Compared to lowland lorises, the Horton Plains loris is "stockier, shorter limbed—and it's got a much longer fur coat."
Ongoing tests on DNA samples taken from the few individuals recorded to date, he added, should help to settle the issue.
__________________
References:
Owen, James. 2010. ""Extinct," Pop-Eyed Primate Photographed for First Time". National Geographic News. Posted: July 19, 2010. Available online: http://news.nationalgeographic.com/news/2010/07/100719-horton-plains-slender-loris-pictures-first-time-science/
Thursday, June 10, 2010
100 Incredible Anthropology Lectures Online
Topics that are covered include; General Anthropology, Modern Culture, Ancient Cultures, Society, Evolution, Archaeology, Linguistics, Technology and Society, and, Primatology. Some of the lectures will end up here individually, like yesterday's post on forensic anthropology. Thanks to Best Colleges Online for compiling the links. (And no, I didn't get paid for this.)
__________________
Best Colleges Online. 2010. "100 Incredible Anthropology Lectures Online". Best Colleges Online. Posted: June 3rd, 2010. Available online: http://www.bestcollegesonline.com/blog/2010/06/03/100-incredible-anthropology-lectures-online/
__________________
Best Colleges Online. 2010. "100 Incredible Anthropology Lectures Online". Best Colleges Online. Posted: June 3rd, 2010. Available online: http://www.bestcollegesonline.com/blog/2010/06/03/100-incredible-anthropology-lectures-online/
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