http://www.emory.edu/LIVING_LINKS/blog/index.php Copyright 2008, Living Links Center for the Advanced Study of Ape and Human Evolution Living Links Center for the Advanced Study of Ape and Human Evolution en-US SPHPBLOG 0.5.1 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080609-134115 Lomas Barbudal, a biological reserve of tropical forest named for its wooded hills and established for the study of its bountiful vengeful stinging insects, this requires tremendous motivation, endurance, and considerable impetuosity as we often plunge down cliffs, through spiky vine tangles, muddy rivers, and into wasp nests with attention monopolized by a monkey traversing the canopy with ease. We also collect fecal samples from the focal throughout the day, which will be assayed for the stress hormone corticosterone.


Sometimes the best view of a monkey is from a rock in the middle of the river. (photo credits: Euan Bowditch)

We are studying the role that social support plays in handling stress, particularly the effects of physical social contact, which is far richer in capuchin society than our own. While in Western culture we might spend an entire day with friends or family and only make physical contact upon greeting or parting, touch is all-pervasive in capuchin interactions. Humans acknowledge the unique potency of physical contact in an interaction, but in part due to its power we relegate it to special situations. Some monkeys of our study population practice an extreme kind of physical contact the function of which is not yet known. Individuals place others’ fingers in their mouth, nostrils, even second knuckle deep into their eye socket. This interaction is often mutual, slow and tranquil. Though the participants are in a very vulnerable position and contact with such sensitive tissues is clearly irritating, as interruptions by sneezing and itching are frequent, they close their eyes and appear to relax throughout sessions that can last for an hour. But not just any monkeys will interact this way; specific dyads develop repertoires of vulnerable contact over an extended period, perhaps allowing them to build up something akin to trust. Following individuals throughout the daylight hours ensures that we will catch these sessions and also record the events that precede and follow them. Over the duration of this study we will be able to observe new dyads develop and perhaps dissolve and how their relationship changes within the group changes with this special bond. This behavior does not appear to be necessary to survive or innate; it has not been observed in all populations of the species, including some groups within Lomas Barbudal. Not all individuals in a group participate, sometimes despite encouragement from those that do, and if key individuals disappear the behavior does as well. Susan Perry, the founder of this research site, has shown that the practice of such behaviors can be traced through individuals. The pattern that emerges over 17 years of research at this site and comparison with others in Costa Rica is one of a social tradition.


Rumour and another adult female relax into the vulnerable contact of mutually sticking fingers into each others' nostrils. (photo credits: Susan Perry)

Rumor is a unique monkey. Most focals constantly challenge our ability to identify their comrades through dense foliage by foraging near others and spending their free time in social clumps; playing, grooming, fighting. Aside from a select few odd affiliations, Rumor rarely interacts, yet when she does, it is in the form of poking other’s digits in her eyes and placing her fingers in theirs nostrils. She is an innovator, always pushing these behaviors to another extreme. Years of observation and genetic data indicate that she is not related to any of her group mates, so creativity may arise from her independence from mothering and a lack of normal bonds with any daughters. Rumor has had female partners but she also practiced these behaviors with the alpha male, who had no other partners and seemed support her in conflicts. Upon his disappearance in June 2007, she became a frequent victim of within group aggression. Months ago a wound that has grown to half the size of her chest appeared and she now seems to lack the energy for anything but essential activities. Following her all day had become dismal business. But this day gave us hope for her and the perpetuation of the vulnerable contact traditions within her group. As she groomed Champingon, a big old male who tends to be peripheral to group drama, she brought his hand to her face and he permitted her to insert his index finger disturbingly far up her nostril. He did not reciprocate, but in the days that followed they had several sessions and he begin to take a more active role. Being back to her old ways bodes well for Rumor’s survival, although her wound still looks horrendous. We don’t yet know what function these behaviors serve, but having a friend who is invested enough in your relationship to let you stick their finger up your nose must certainly help one though rough times.

]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080609-134115 Living Links Center for the Advanced Study of Ape and Human Evolution Mon, 09 Jun 2008 17:41:15 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=06&entry=entry080609-134115 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080401-093359
It’s amazing how silent elephants can be if they want to. They walk up to you without you ever noticing, walking on velvet cushions, with a very flexible gait, and in fact much faster than you’d think. We always imagine elephants as stamping, sending vibrations through the ground, but I felt I had to watch my back standing among them at the Elephant Nature Park, near Chiang Mai, and later the Thai Elephant Conservation Center, near Lampang. The big difference with most observers of African elephants is that one is NOT in a Jeep: one stands there next to these mighty beasts and one senses right away how tiny and vulnerable the human race is.

Elephants are magnificent. But the elephant story in Thailand is also a sad story of changing habits and increasing neglect and abuse. This is why the above centers exist: to collect elephants abandoned by their owners or elephants in poor physical shape (such as land-mine victims), so as to provide them with appropriate retirement at a facility with excellent food and care. All elephants have a mahout who keeps them under control, which is the only way of caring for elephants short of releasing them. The latter may seem preferable, but in a populated nation such as Thailand, and given the danger elephants pose to people, “liberating” the elephants means almost certain death hence is not really an option.

I was thoroughly impressed by the commitment of those who care for them, who devote their lives to making sure the elephants can either live with others either under semi-free conditions or in a situation where they conduct shows and trainings, including music performances and demonstrations of how elephants were used in the logging industry.



At the Thai Elephant Conservation Center, I found it fascinating to see the degree of cooperation elephants are capable of. Our own research is of course not on trained behavior, or musical performance, but rather on spontaneous social skills, including coordination between individuals. The fact that elephants can be trained, however, to walk in perfect synchrony side-by-side, carrying a log between them while the mahouts on their heads are chatting and laughing and looking around (hence, certainly not directing every move), must mean that these animals are natural cooperators. Training is obviously part of the picture, but one cannot train any animal to be so coordinated. One can train dolphins to jump in synchrony because they do so in the wild, and one can teaches horses to run together at the same pace because wild horses do the same. For the same reason, one can train two elephants to pick up a log together and carry it to another place, walking in perfect synchrony, and lowering the log slowly together to set it down at the very same second on a pile, because elephants must be extremely coordinated in the wild.

I will leave it to Josh to report on the social behavior observed in these animals, but I came away with a deep admiration for them as their intelligence and sociality seemed on a par with those of the primates.



At the Elephant Nature Park, the animals are semi-free. They are always accompanied by mahouts, but relatively free to explore the environment and interact with other elephants.

]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080401-093359 Living Links Center for the Advanced Study of Ape and Human Evolution Tue, 01 Apr 2008 13:33:59 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=04&entry=entry080401-093359 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080324-075654
Alda made a return visit to the Living Links Center to discuss primate behavior and cognition as part of the upcoming PBS series entitled “The Human Spark,” which he will be hosting.

Along with producer Graham Chedd, our research team had the privilege of spending the day discussing our most recent findings regarding chimpanzees and capuchins from an evolutionary perspective. Alda’s genuinely curious nature and extensive travels were the groundwork for an enlightening exploration of our closest living relatives, and our understanding of human evolution.

For the purpose of this unique series, Alda has journeyed to various locations around the globe to document how primatologists are investigating empathy, culture, tool use and cooperation among chimpanzees. The Living Links team had the opportunity to sit down with Mr. Alda and discuss our research in detail, focusing on the connections between humans, apes and monkeys. From the tower overlooking one of the large outdoor chimpanzee enclosures, Dr de Waal explained various food-sharing behaviors as the chimps enjoyed coconuts, watermelons and sugarcane. Alda’s crew also filmed some of the social learning experiments that have been conducted with chimpanzees by our team over the past couple of years. As the filming took place, chimps eagerly participated in different cognitive and tool-use tasks in order to retrieve food rewards. For Alda, witnessing the complexity of the negotiations and the distribution of prized food items as well as the problem-solving abilities amongst the chimpanzees seemed to authenticate some of the key elements of “The Human Spark.”

Overall, Alan Alda and the PBS crew provided our research team with an exciting opportunity to explain our evolutionary similarities and differences with non-human primates. The series is currently planned to air in 2009 and we are grateful to have participated.

Just before we sat down for lunch with Mr. Alda, we had a chance to grab a quick photo. From left to right: Darby Proctor, Victoria Horner, Matthew Campbell, Frans de Waal, Alan Alda and Devyn Carter.

]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080324-075654 Living Links Center for the Advanced Study of Ape and Human Evolution Mon, 24 Mar 2008 11:56:54 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=03&entry=entry080324-075654 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080305-114333 Cape of Good Hope area of Table Mountain National Park in South Africa. I was working on a spatial ecology project with Tali Hoffman of the Baboon Research Unit (BRU) at the University of Cape Town.

The chacma baboons of the Cape region are cut off from the rest of the African continent by the urban area of Cape Town. As such, they are a critically endangered group of monkeys. There are only around 350 individuals left in the peninsula. Living on the edge of one of the largest cities in Africa, these baboons can provide valuable information about how human encroachment can effect the behavior and ecology of wild primate populations. Yet, little published research has been done on this population. Thankfully, BRU is now actively pursuing research on a number of aspects of the baboons’ daily life, from their basic spatial and foraging ecology to the effect of being followed by human monitors on their ranging patterns. You can read more about the work being done by BRU here.



After spending only a month with the baboons in the Cape I feel as though I only have a fleeting impression of their behavior and their situation with their human neighbors. As such, I will share with you a couple of the more interesting things I learned from this trip. Prior to leaving, most of my knowledge of baboons came from extinct fossil forms (see my masters thesis) and the behavior of the well studied hamadryas baboons of eastern Africa, who are known for their male dominated social interactions. One of the first things that surprised me was how tolerant the male baboons in the Cape are of infants. The infants often play around and with adult and sub-adult males. It is even a frequent sight to see a male carrying an infant on his back. I was totally unprepared for this level of male involvement in the rearing of young. Such male behavior is relatively rare in primates.

Perhaps one of the most touching instances I witnessed of male care came when a group of about four males moved a few hundred yards away, through dense vegetation, from the rest of the group. One of these males had an infant on his back. Since the vegetation was more dense where all the females were, I followed the group of males and the lone infant. The males and this infant started foraging on some short grass. As a researcher I always tried to be as unobtrusive as possible and stood apart from the baboons. However, despite standing to the side as the males and infant foraged, the infant became alarmed at my presence and started screaming. Instead of the male becoming alarmed, or a female rushing to the aid of an infant in distress, the closest male simply made gentle grunting sounds, which are a reassurance/friendly gesture in baboons. The male kept making this gentle call until the infant ran to him and calmed down. It was incredible to me that the infant’s mother, who was some distance away, did not rush to the aid of the infant, but rather seemed to trust this male care-taker. You can hear an example of this reassurance call here.

Of course, being in the field is not just watching baboons do cute things. Especially in the Cape region much of what I learned was how these baboons are impacted by, and in turn affect the human population around them. In some of the smaller towns in the peninsulas baboons are habitual raiders of human areas including garbage cans and even houses. Not only is this inconvenient for humans, but it is dangerous for baboons as they come into contact with unhealthy human food and any diseases the humans may have. Recently, human monitors have been employed to keep the baboons from going into the more dense urban areas. This is quite effective at keeping the baboons away, but it is unclear what effect the monitors will have on the baboon’s long-term behavior.



I worked specifically within the national park around the Cape of Good Hope, so the baboon/human contact issue was somewhat different, but raiding was still a problem. The park also utilizes monitors to keep the baboons away from areas that humans frequent, such as the visitors center. This would be extremely effective, if it were not for the tourists. Tourists, who drive through the park, generally stop on the side of the road whenever they see baboons. This would be fine if the tourists just sat in their cars and had a look at the baboons. Unfortunately, many tourists do not seem to grasp the fact that baboons are wild animals and can be quite dangerous, especially if the tourist has food. Instead, I saw tourists throw food from their cars and in some cases even hand food to a baboon. This only leads to the baboons learning that tourists are a source of food and rewards them for being aggressive toward humans, who will drop their food if a baboon charges at them.

So, what is the solution? How can humans and primates live in close proximity? That is a complex question and one that is being explored in many primate species across the world as humans move more and more into previously “wild” areas. It seems to me that there is no quick, or easy, or cheap fix. Perhaps where we need to begin in order to conserve these baboons, and other primate species, is with public education of the people that live in those areas. Only by including, and empowering the local people can primate conservation be successful.

For more general information on baboons click here .
]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080305-114333 Living Links Center for the Advanced Study of Ape and Human Evolution Wed, 05 Mar 2008 16:43:33 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=03&entry=entry080305-114333 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080304-121626
In the wild, capuchin males will leave their natal group and find another group to take over and become the alpha. This involves physically ousting the current alpha male and gaining support of the resident females. In Bravo’s case, we transferred the previous alpha male to another facility and Bravo, being the second in line and the largest male in the group, was the obvious choice for alpha. In addition, he already had support from the main females in the group, Star, Sammie and Bias. In the picture below Bravo is the large male in the center who is being groomed by Sammie. Star, the alpha female, is on the left and Snarf is on the right.



In the months following his unanticipated promotion to alpha male, Bravo enjoyed the benefits of his new position, namely eating first and mating with the females, but declined to perform some primary alpha duties, such as intervening during group conflicts. This has allowed the alpha female, Star, to have an abnormal authority over the group. Waiting in the wings has been our beta male, Mason. Mason often defends the lowest ranking individuals of the group and harasses the offspring of the highest-ranking females. As Bravo’s transfer date draws closer, we are uncertain whether Mason will realize that he is now eligible for the alpha position, particularly given our previous experience with Bravo. However, there is one major difference between Bravo and Mason’s accession, namely that Mason does not have the female support that Bravo had. This may require Mason to take an active role in acquiring the alpha position. During the coming weeks we will be closely monitoring the group to see how this succession transpires and whether Mason will pursue support from the females. Likewise, we will observe how the females respond to Bravo’s absence and Mason’s expanding authority.
]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080304-121626 Living Links Center for the Advanced Study of Ape and Human Evolution Tue, 04 Mar 2008 17:16:26 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=03&entry=entry080304-121626 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080211-104938 lab's two focal species, chimpanzees and capuchins, in favor of a
slightly larger, yet still highly intelligent mammal, the elephant.
Yesterday, I sat in a field in a northern Thai jungle watching a
group of semi-captive Asian elephants ever-so-slowly grazing on a
large plot of jungle grass. As is often the case, one of the young
infants in a family group of 5-6 individuals wandered away from her
family and over to one of the males in musth - a period during which
bull elephants are often aggressive and "hormonal," and playfully
began to tease him, chirping - repetitive, often high-pitched sounds
that elephants make for a variety of reasons including excitement -
and backing in and out of the bull's trunk range. All of a sudden,
for no apparent reason (at least not for one my eyes or ears could
pick up), she let out a loud, infant-specific squeal. Three of the
four females standing on the other side of the field immediately
responded, and with their ears out, tails raised and legs in a full-
on sprint, each let out loud trumpet bursts before they reached the
"lost" infant. They immediately circled around her, all facing
outward while they kept her enclosed in the middle, touching her with
their trunks and continuously rumbling, while obviously paying
careful attention to the surrounding environment. A few minutes
later, the fourth individual, slowly walked over to the infant,
touched her face, and resumed her morning grazing.



Such infant-centric behavior is not uncommon in elephants, and
African elephant researchers J. Poole, C. Moss, K. Payne and I.
Douglas-Hamilton have all described it in their own investigations of
elephant behavior. But something sticks out here - the fourth, less-
interested elephant is in fact the infant's mother. The other three
elephants are the infant's "aunties," and although they all share a
place in what appears to be a cohesive family unit, they are all
completely unrelated to the infant, and each other. The complexity
of such cooperative and seemingly empathic behavior is one of the
many areas on which I hope to focus my research here. If you'd like
to find out more, feel free to contact me at jplotni@emory.edu. ]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080211-104938 Living Links Center for the Advanced Study of Ape and Human Evolution Mon, 11 Feb 2008 15:49:38 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=02&entry=entry080211-104938 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080201-172050

A recent study in Science by Esther Herrmann et al. (7 September 2007, p. 1360) claims equivalence in technical skills between apes - chimpanzees and orangutans - and two-year-old human children, but inferior social skills in the apes. These results are taken as support for a “cultural intelligence hypothesis.”

The study features an impressive battery of tests, seemingly administered in the same format to apes and children. It has been pointed out before, however, that the easiest way to standardize conditions – by having a human experimenter provide the social cues - introduces handicaps for the apes. When the experimenter is human for all subjects, only the apes are dealing with a species other than their own. This may not be as relevant for physical or technical problems, which focus on inanimate objects, but one expects this to matter for social tasks which rely crucially on the relation between experimenter and subject. The reported findings are consistent with the apes being handicapped specifically in the social domain.

The differences between the set ups for children and apes in this study appear multifold. Human children sit on or next to their parent (introducing potential “Clever Hans” effects), are talked to, are used to dealing with human strangers, and are tested by a member of their own species. The apes are alone, observe the task from behind a barrier, receive no verbal instructions, and are tested by a species not their own. We are not suggesting that human experimenters should never be used, but that the social skills which matter most for apes, especially as they relate to culture, are those shown with conspecific models.






Study set-ups for children (above) and chimpanzees (from Hermann et al 2007, online material)

In fact, evidence for ape-to-ape social learning is plentiful. Studies of wild chimpanzees in Africa have documented an impressive array of group-specific traditions attributed to social learning. Apes tested with a human model whom they have grown close to, or with a familiar member of their group, have recently demonstrated social learning that has extended to high-fidelity cultural transmission within and between groups. For the latest studies on this, explore our cultural learning website.

These findings conflict with the results as well as the central thesis of Herrmann et al. Ignoring this literature, as they have chosen to do, can only lead to a fragmented literature, a situation exacerbated by the fact that a “cultural intelligence hypothesis” already exists, formulated to explain the cultural complexity of both humans and the great apes. Mysteriously, given the title of Herrmann et al.’s article, this earlier usage of the term also remains uncited. We strongly urge testing of cognition in ecologically valid settings, such as testing social skills with conspecifics. The problem of the human model would be even more severe in relation to Herrmann et al.'s proposal to extend their test battery to more distantly related species.

As a thought experiment, ask what would happen if we trained apes to apply tests to human children so that these, too, faced a species-barrier. We doubt that this would do the children’s performance any good!


For further reading on the controversy of how to fairly compare apes with children, see the following two publications:

* Chapter 6 of de Waal, F. B. M. 2001. The Ape and the Sushi Master. New York: Basic Books.
* Boesch, C. 2007. What Makes Us Human? The Challenge of Cognitive Cross-Species Comparison. J. Comp. Psychol. 121: 227-240.


]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080201-172050 Living Links Center for the Advanced Study of Ape and Human Evolution Fri, 01 Feb 2008 22:20:50 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=02&entry=entry080201-172050 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080123-135759
It was a bitterly cold Atlanta day, with temperatures hovering around freezing and the constant threat of rain. Not the sort of weather that a film crew likes to contend with, but the date for Prof. Dawkins’s visit had been set for many weeks and so the show had to go on. He was here to film an interview with Dr. de Waal as part of his upcoming TV series 'Origin of Species', and hopefully, weather permitting to meet the chimpanzees as well. The topic of the show is evolution, and so he was interested in Dr. de Waal’s perspective on the evolution of emotions, based on behaviors such as helping and food sharing that he has observed in both the Arnhem and Living Links chimpanzee groups.

The film crew arrived early to set up all their equipment at the FS1 chimpanzee enclosure while the chimpanzees looked on, curious and excited – film crews usually mean food treats! Given the temperature, we were surprised that the chimpanzees chose to be outside at all, rather than in their heated indoor building, but apparently their curiosity in the film crew (or perhaps it was their unfamiliar British accents!) kept their interest peeked enough to brave the cold.

Once the cameras were in place, the microphones switched on, and the watermelons put into the enclosure, Prof. Dawkins and Dr. de Waal discussed the topic of emotions while the chimpanzees tucked into their morning snack. The film crew got some good footage of food sharing and grooming, and the interview went well, despite having to pause every once in a while to avoid the noise of aircraft landing at a nearby airstrip.



Unfortunately Prof. Dawkins had to leave as soon as the interview was done due to prior commitments in his busy US tour. But we did have time for one quick photograph (from left to right: Devyn Carter, Matthew Campbell, Frans de Waal, Richard Dawkins & Victoria Horner). All in all, the visit was a great success, although we were glad to get back into the warm, chimpanzees and humans alike.

-- Victoria Horner]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry080123-135759 Living Links Center for the Advanced Study of Ape and Human Evolution Wed, 23 Jan 2008 18:57:59 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=08&m=01&entry=entry080123-135759 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry071206-104723
These chimpanzees live in a region that is a mixture of forest and grassland with highly seasonal rainfall. The habitat is believed to be both the limit of what chimpanzees can tolerate, and similar to what early hominins at one point occupied. The thought process is that since our early human ancestors made the transition from forests to grasslands, discoveries like this one offer a glimpse into what behaviors these ancestors may have been capable of, and thus how this transition may have begun. As fascinating as this discovery is, many of the conclusions and implications for human evolution were already known from a different source, un-cited by the authors, several thousand miles and many millions of years of evolutionary time away.

Three years ago scientists in Brazil directly observed and videotaped capuchin monkeys digging for tubers using stones. De A. Moura and Lee were the first to observe an animal, any animal, using tools to dig up food outside of humans. What can the behavior of a monkey, with whom we diverged roughly 35-40 million years ago, tell us about human evolution? Well, quite a bit, actually. The capuchin monkeys observed digging live in a dry forest with highly seasonal rainfall at the limit of what this species is believed to tolerate (sound familiar?). The authors of the chimpanzee study conclude that digging for tubers “need not have required a technology that preserved in the archaeological record,” This is in reference to the stick tools used by chimpanzees, but the unmodified stone tools used by capuchin monkeys already demonstrated that. Hernandez-Aguilar and co-workers also say “the discovery that savanna chimpanzees use tools to obtain USOs [underground storage organs, jargon for tubers] shows that such consumption was within the grasp of chimpanzee-like hominins.” Again, this was implied by the capuchin monkeys doing the same, as it demonstrated that the behavior could evolve without modern human-sized brains.

Most importantly, the authors “argue that chimpanzees adapting to such extreme (for them) conditions can be used as models for investigating particular aspects of early hominin behavioral ecology.” It seems appropriate to add capuchin monkeys to that statement. Why? Analogous (or convergent) evolution, when unrelated species independently evolve similar adaptations, can be just as informative as homologous evolution, when adaptations share a common origin. The conditions under which the separate behaviors evolved may be similar, and thus informative, especially when examples from close living relatives are not known or do not exist. In our desire to fully understand human origins, we must not focus only on our closest relatives for answers. The Living Links to our past are all around us; we only need look for them.


Matthew Campbell


Video of a capuchin digging for tubers


Full references to the articles mentioned:

de A. Moura, A. C., & Lee, P. C. (2004). Capuchin Stone Tool Use in Caatinga Dry Forest. Science, 306(5703), 1909.

Hernandez-Aguilar, R. A., Moore, J., & Pickering, T. R. (2007). Savanna chimpanzees use tools to harvest the underground storage organs of plants. Proceedings of the National Academy of Sciences, 104(49), 19210-19

]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry071206-104723 Living Links Center for the Advanced Study of Ape and Human Evolution Thu, 06 Dec 2007 15:47:23 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=07&m=12&entry=entry071206-104723 http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry071203-173015
In a new study published in Current Biology (Vol. 17, p1004) Inoue & Matsuzawa found that Ayumu, a 5-year-old chimpanzee, could outperform both his mother, and a group of university students in a computer task designed to investigate working memory. In the study, participants saw 5 Arabic numerals (from a set of 1 through 9) presented in a random location on a touchscreen monitor. The aim of the task was to touch each numeral in the correct ascending order. But, there was a catch. The numbers appeared on the screen for only a fraction of a second before being replaced by a white square; so fast, in fact, that the presentation was ‘subliminal’. Ayumu was quicker and more accurate than either his mom or the humans, demonstrating a phenomenal ability for symbol recall and working memory. The authors discuss their findings in relation to the evolution of language and symbolism.

See Ayumu perform here.

View more video clips from the Kyoto Primate Research Institute website here.

For me, the findings of this study have additional implications for how we conduct comparative studies of cognition. Many cognitive studies are motivated by evolutionary questions about whether other species share the same cognitive abilities as us. However, because such studies are often intrinsically human-centric, they tend to utilize methodologies that inadvertently favor humans while posing handicaps for the apes. However, the studies we conduct at the Living Links Center involve chimps learning from fellow chimps, and in these more natural conditions we find that this is something they are rather good at, in fact so good that they have developed their own distinct cultures. The study by Inoue & Matsuzawa is particularly interesting because it is initiated from an unusual perspective: rather than asking whether chimpanzees can do what we do, the authors have taken a skill at which their chimpanzees were particularly good and then ask if we can do what they do. It seems that when the tables are turned like this, we don’t always come out on top. For me, this study highlights the importance of casting a wide net when searching for cognitive abilities within the animal kingdom. If we only ever study other species to see if they share our cognitive abilities, we may miss important features of their cognition and learn little about abilities we may have lost.

RECENT UPDATE
Ayumu trounces British memory champion!

Click here for more studies in which chimpanzees outperformed humans.

Think you can do better than a chimp? Give it a try here!

--Victoria Horner
]]> http://www.emory.edu/LIVING_LINKS/blog/index.php?entry=entry071203-173015 Living Links Center for the Advanced Study of Ape and Human Evolution Mon, 03 Dec 2007 22:30:15 GMT http://www.emory.edu/LIVING_LINKS/blog/comments.php?y=07&m=12&entry=entry071203-173015