Primatology.net

Gorilla Protection links us up to an excellent report done by Al Jazeera on the threats to mountain gorillas. It’s a bit long, but it is really well done. Before you check out the video, another dead gorilla has been found.

With all the depressing news of gorillas being slaughtered and primates being brought closer to extinction, I wanted to share this photograph of an abandoned baby macaque, who was taken in by an animal hospital in Goangdong Province, China. He was very lonely until he made friends with a white pigeon.

In many cultures, the white pigeon or dove, is a symbol of peace and hope. It seems like this little birdy brought a lot of hope to this little macaque… two are now inseparable, and make for an awfully adorable friendship.

Read more about their heartwarming story over at the Daily Mail.

P.S. Doesn’t this remind you of the baby orangutan and tiger friendship?

A PLoS One study of chimpanzees at Bossou in Republic of Guinea, shows that the male chimpanzees raid farms and orchards for fruit that they steal and bring back to the females. In exchange, the males shared their fruity booty with the females in a food-for-sex trade.

The photo to your right shows one of the sneaky males climbing a cultivated papaya tree to harvest some fruit. The look on his face is priceless.

Of all the evolutionary psychological studies involving chimps I shared with you this past week, this one “Chimpanzees Share Forbidden Fruit,” is the most remarkable. Here’s the abstract, the full text of the article is openly accessible for anyone to enjoy reading in first hand,

“The sharing of wild plant foods is infrequent in chimpanzees, but in chimpanzee communities that engage in hunting, meat is frequently used as a ‘social tool’ for nurturing alliances and social bonds. Here we report the only recorded example of regular sharing of plant foods by unrelated, non-provisioned wild chimpanzees, and the contexts in which these sharing behaviours occur. From direct observations, adult chimpanzees at Bossou (Republic of Guinea, West Africa) very rarely transferred wild plant foods. In contrast, they shared cultivated plant foods much more frequently (58 out of 59 food sharing events). Sharing primarily consists of adult males allowing reproductively cycling females to take food that they possess. We propose that hypotheses focussing on ‘food-for-sex and -grooming’ and ‘showing-off’ strategies plausibly account for observed sharing behaviours. A changing human-dominated landscape presents chimpanzees with fresh challenges, and our observations suggest that crop-raiding provides adult male chimpanzees at Bossou with highly desirable food commodities that may be traded for other currencies.”

If you don’t believe what you’re reading the authors provided two video clips showing some sly and slick male chimp entering what is obviously and occupied by humans (because of the buildings) climbing a tree, stealing fruit, and making a mad dash as if he were a bandit. Then he shares an intimate moment with his lady friend, munching on some fruit.

I’ve edited the clips together and put them up on YouTube for all y’all who can’t play the file types they provided.

The American Journal of Primatology has published a paper by primatologist Kimran Miller and colleagues, who studied urine washing behavior among a population of capuchin monkeys. Prior to this study there have been some wild claims as to why so many monkeys pee on themselves. Some of them are:

• Peeing one oneself helps the monkey improve their grip when climbing.
• Urine washing is a type of cooling mechanism done when it gets too hot.
  

But this new study from Miller suggest that urine washing among monkeys is all about social communication. From Nature‘s news coverage,

“Alpha males, for example, doubled their urine washing rates when being solicited by females. The researchers think this might be how males encourage females to continue paying attention once they’ve started.

And in 87% of fights or aggressive incidents, the loser of the battle washed in urine. The team suspects that this is also an attention-seeking behavior — in this case seeking sympathy. But more research is needed to be sure.“

I’d link you up to the original source article if only Wiley InterScience wasn’t down at the moment.

Pattty, one of our regulars, emailed me with this hilarious advertisement involving a man dressed up as a gorilla and rocking out to Phil Collins. I’m pretty sure it will liven up your Monday blues.

Right on the heels of yesterday’s two primate psychology posts involving chimps comes news that captive chimpanzees have been observed to flip through National Geographic magazines that calm them down. I wouldn’t have found this if it weren’t for Neatorama‘s post. The observations have been written up and published in Biology Letters. Here’s the paper, ” Chimpanzees use self-distraction to cope with impulsivity.”

For the most part chimps are really rambunctious primates, especially in captivity. They are always impulsive and intense, but psychologists Theodore Evans and Michael Beran of the Georgia State University saw a different animal when they were given magazines to preoccupy themselves with after exciting them with candy.

Their experiment involved observed four adult chimpanzees that were first given a candy dispenser. The candy was given to them every 30 seconds but as soon as the apes reached to get the accumulated candy, the dispenser stopped delivering. This sort of teasing tested the chimps’ patience; a greater award was offered if they resisted their impulses, they would earn a greater award.

And when they were given a set of toys, like magazines, toothbrushes, and tubes, they were significantly better at coping with temptation when they could entertain themselves. Without toys, the chimps could only hold out for about 7 minutes to get a measly 11 candies but when toys were around they waited almost 10 minutes to get a total of 17 candies. Evans remarks,

“The magazines included some National Geographic, Entertainment Weekly, and Atlanta food and wine circulars, among others. The chimps would slowly page through the magazines, probably looking at the pictures—research suggests that they perceive pictures as real objects like humans do. They used the toothbrushes as we would. They appeared to enjoy the bristle texture in their mouth and on their teeth.”

And Beran,

“Humans like to think that they can control themselves better than can animals, and yet this type of research suggests that the story is not that simple.”

So in conjunction with the expectation of rational behavior and cognition skills, here’s another once-thought-of-human-only behavior that is documented in humans.

I don’t normally make out pleas to help out each and every conservation organization but my friend Allison, who worked for the following organization, told me about what’s happening to it and this one is really serious.

First some background, the conservation organization is speak of is the Comunidad Inti Wara Yassi, a wildlife refuge in Parque Machía, near Villa Tunari, Bolivia. They house many animals, such as capuchin, spider, and squirrel monkeys. Recently, Jane Goodall did a special for Animal Planet where she listed her 5 heroes and she chose the founder, Juan Carlos Antezana, as her final one in the show. They are a great organization and do much more than help save wildlife.

The bad news is that Inti Wara Yassi is in jeopardy and the animals need our help! Some of the land they use for facilities such as the veterinary clinic, monkey quarantine and small animals area will be sold off by the landlord if they don’t raise $30,000 USD within two weeks. Sounds like black mail to me… the loss of these facilities may mean the animals die. That’s a lot of monkeys that will lose their lives because of this petty situation.

Please help out Inti Wara Yassi! Some money has been donated but it ain’t $30k yet! Any little bit helps…You can donate money directly to the organization by visiting the site and you can also help spread the word and bring attention to this situation by digging up this on Digg.com. That way thousands more people will read about it and potentially help.

From this news release, is this Science paper, “The Perception of Rational, Goal-Directed Action in Nonhuman Primates” where Justin Wood of Harvard’s Psychology department and colleagues., figure out that primates expect one another to act rationally. How?

Well Wood and crew setup two sets of experiments that tested the behavioral response of over 120 primates, including cotton-top tamarins, a type of New World monkey, rhesus macaques, a Old World monkey and chimpanzees to represent the apes.

I have been confused about the design of the first experiment, which the tested the primates by presenting them with two potential food containers. One container was grasped by the scientists on purpose and the other container was accidentally grasped by flopping their hand on top of it. I probably didn’t do a great job translating the setup, so forgive me.

The most sense I can make out of what was tested here is the ability to understand or differentiate goal-oriented and accidental behavior. And the results show that in all three species, the primates picked out the the food container that was purposefully grasped more often than the container upon which the hand was flopped. This indicates that the primate inferred goal-oriented action on the part of the experimenter when he or she grasped the container, and was able to understand the difference between the goal-oriented and accidental behavior.

In the second experiment, the primates were also presented with two potential food containers but this time the researchers sought to answer if the primates can infer others’ goals under the expectation that other individuals will perform the most rational action allowed by the environmental obstacles. In one situation, an experimenter touched a container with his elbow when his hands were full, and in another scenario, touched a container with his elbow when his hands were empty. And low and behold, the primates looked for the food in the container indicated with the elbow more often when the experimenter’s hands were full.

The primates considered, just as a human being would, that if someone’s hands are full then it is rational for them to use their elbow to indicate the container with food, whereas if their hands are empty it is not rational for them to use their elbow, because they could have used their unoccupied hand.

Wood comments on his paper,

“A dominant view has been that non-human primates attend only to what actions ‘look like’ when trying to understand what others are thinking. In contrast, our research shows that non-human primates infer others’ intentions in a much more sophisticated way. They expect other individuals to perform the most rational action that they can, given the environmental obstacles that they face.

This study represents one of the broadest comparative studies of primate cognition, and the significance of the findings is reinforced by the fact that these results were consistent across three different species of primates. The results have significant implications for understanding the evolution of the processes that allow us to make sense of other people’s behavior.”

What sorta significance? Well this study kinda sorta implies that the ability to engage in this type of rational action perception evolved as long as 40 million years ago, with non-human primates, and that it is not a human only response… possibly this sort of behavior was positively selected for in the primate lineage and ultimately folds into the social brain hypothesis. Speaking of which, you may also wanna check out the evolution of the social brain, which also debuted in the latest Science, while you are at it.

The web seemed to have exploded with news covering this hot-off-the-press open access Science paper, “Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis.” Before I jump into the paper, here are some news sources wrote about this paper:

• Higher Social Skills Are Distinctly Human, Toddler And Ape Study Reveals – ScienceDaily
• Children outsmart chimps – telegraph.co.uk
• Toddlers outdo chimps at apeing the grown-ups – The Times
• Humans’ Complex Social Skills Due to Larger Brains – National Geographic News
• Higher social skills are distinctly human, toddler and ape study reveals – EurekAlert

You really don’t need to read each one of the news sources, because they all are saying the same thing, human toddlers are more sophisticated in their social learning skills than their closest primate relatives. It is not that Earth shattering of a conclusion, even though the average human toddler brain How did the authors get to this outstanding conclusion?

Well first author, Esther Herrmann of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues put 106 chimpanzees, 32 orangutans, and 105 young German children through a series of complex tests. The kids were around two-and-a-half years old and had been speaking for at least a year and the other non-human apes had all been made accustomed to humans.

The tests were 16 different puzzles designed to weed out the differences in ability between humans and apes. Some of the puzzles included tracking the position of a reward under a cup, a very famous game that tests observation and concentration, and selecting the cup that the researcher pointed to, involved social skills such as communication. Esther demonstrates the test in the image on your right.

The results found that chimpanzees, orangutans, and human children were all generally equal the physical skills tests. But the human children were better at the social skills tests—scoring around 74 percent correct on the tests compared to scores of 33 percent from both groups of apes. I’ve attached Figure 1, from the paper, below for you to see how ‘significant’ human kids preformed better than chimps and orangutans in the social domain… and to be honest it isn’t that significant.

You ask, “Why isn’t it that significant, Kambiz?” Well, do you see the bars above and below the gray boxes in the graph? Those represent the range of values the authors recorded, and in the social domain the human kids lowest range overlaps with the chimpanzee’s highest range. That kinda indicates that either their testing wasn’t thorough enough, i.e. they needed to increase the sample size or add another test to spread out the difference… OR that there really isn’t much of a significant difference.

But there is one example provided were human kids were way better. This test involved a human adult demonstrating how to retrieve food from a transparent tube by popping it open, and the children were almost always able to copy the action immediately and accurately and get the reward. Both ape species, by contrast, failed to understand what the experimenter had done, and instead tried to bite or tear apart the tube to get at the food.

Esther suggests that these tests document that higher social skills are uniquely human, and that it particularly applies to a concept known as “theory of mind” – essentially being able to see things from another’s point of view,

“Social cognition skills are critical for learning. The children were much better than the apes in understanding nonverbal communications, imitating another’s solution to a problem and understanding the intentions of others.

The current results provide strong support for the cultural intelligence hypothesis, that humans have evolved some specialized socio cognitive skills, beyond those of primates in general, for living and exchanging knowledge in cultural groups. Young human children who have been walking and talking for about a year, but who were still several years away from literacy and formal schooling, performed at basically an equivalent level to chimpanzees on tasks of physical cognition, but far outstripped both chimpanzees and orang-utans on tasks of social cognition.

This was true at both the most general and the most specific level of analysis, for individuals never before exposed to these tests, and across the most comprehensive test battery ever given to multiple primate species.”

As you may know humans have the largest brains of all the primates and there are two main theories as to why humans have evolved larger brains than our other relatives. The first, called the “general intelligence hypothesis” suggests that humans’ bigger brains make us better and faster at all kinds of skills, such as memorizing, learning, and planning ahead. But the second, called the “cultural intelligence hypothesis,” suggest that larger brains have specifically enabled us to develop more complex social skills. Herrmann comments,

“This [study] contradicts the general intelligence hypothesis. We would have expected to see a difference in physical skills as well if the general intelligence hypothesis was right.”

That makes sense, our bigger brains enable us to cope with the complexities of social life… but that graph is still not significant enough for me to write one theory over the other.
Additional and related reading from two of the authors:

• “Apes’ and children’s understanding of cooperative and competitive motives in a communicative situation,” Developmental Science, 2006.

Vanessa Woods, whom we’ve mentioned on Primatology.net before, has started a new blog titled, “Bonobo Handshake,” where she will document her current research trip to study endangered bonobos in Congo. She’ll be writing from Lola ya Bonobo Sanctuary.

There are already a number of awesome blog posts where she documents the her field research.

I’ve added it to my RSS reader, and will add it to the Primatology.net link page… I recommend you do the same!