Week 13: Assessing Cognition in Apes


The Ape Genius video was a great way to learn more information about cognition in primates, specifically how we can assess these various levels of cognition. The main purpose of the video, as it started out, was to investigate the differences between human cognition and primate cognition. The researchers noted that they wanted to try to discover the small differences between human and animal cognition that created big differences between behavior and overall species capability. The way to go about answering this question was to ask the question: what kind of ape mind will lead a species to culture? The main conclusion that these researchers came to was that “culture” in apes was passed down based on a juvenile’s ability to copy behavior that he or she witnesses in older individuals.

A study that was conducted to assess cognition was designed based around a chimp’s ability to receive fruit rewards. A “slot – machine” like apparatus was designed where the chimpanzee had to turn a disk to release the grape, and then press a lever to actually receive the grape. While assessing how the chimp learned to get the grape, the researchers were able to determine how this individual chimpanzee learned through trial and error as well as imitation. Another way to study cognition that the video Ape Genius touches on includes studying tool usage in primates. My favorite study, however, was the one that involved a chimpanzee who was required to move a large block. After a while it became very clear to the chimpanzee that he would not be able to move it on his own and he sought out the researcher and led the researcher over to the box to help move it. In subsequent trials, the chimpanzee asked for help quicker.

One thing that I particularly liked about the video was how well it addressed the topic of anthropomorphism, which we have spent much time discussing in this class. The video, at one point, mentions that it is difficult to say what the animals are thinking. It is easy to anthropomorphize animals, especially apes – who are so similar to humans – but researchers must always be wary of those tendencies. By anthropomorphizing cognition in apes and other primates results can get cloudy, or we can be quick to jump to conclusions. What I think the video did particularly well, however, was refusing to discount the emotions that we can witness in primates. The video notes that while studying cognition in primates, such as facial expressions, visual communication, and other means of communication that it is “hard to dismiss their feelings.” These researchers, though barring all preconceived notions of cognitive abilities and thoughts are at the same time addressing emotions or other cognitive experiences beyond just the behavioral and learned component.

This aspect, I think, expresses how the video made it a point to compare humans and animal cognition because of our relationship within the animal kingdom. Through the video I was able to see how cognitive studies on apes can break down the boundaries we have built between humans and “beasts.” Learning by imitation is not present in only humans, and that forces us to reformulate what actually separates us from our closest relatives.


This experiment is to test working memory in chimpanzees, while assessing their ability to understand what the study calls “symbolic representation,” meaning they used numerical sequences.

The chimpanzees come in voluntarily to participate in the research study. Each one uses a computer monitor to follow various sequences. They eventually learn numerical sequences and can touch the correct numbers in the correct order. If an incorrect number is touched, the sequence starts over. This was impressive to me, but there’s more. After the sequence has been finished, it starts over. The chimpanzee can then touch the numbers in the correct order, even though the numbers are masked. These tasks are very difficult, and show that sometimes the chimpanzees.

The conclusions showed that some younger chimpanzees have better working memories than adult humans, but when it came to symbol matching they were much less proficient. These results show similarities and differences in human and chimpanzee cognition.

I liked how this study showed how the chimpanzees were being taken care of, and the video starts off by showing the layout of the research station, and how it is structured like a chimpanzee natural environment. I do wish, however, the study could have provided other means of assessing memory, because it is such a general term, and perhaps it could have been studied with several different tasks.


Matsuzawa T. 2009. “Symbolic representation of number in chimpanzees.” Curr Opin Neurobiol. 19(1): 92-98.

Week 6: Bonobo Sexuality


I’ll be honest, I don’t think all of us have moved past our middle school days when any mention of sexuality in a professional (classroom) setting ignited an upsurge of snickers and giggles. Well, hold your laughter, because the bonobo’s wouldn’t see what’s so funny. The Bonobo, or Pan  paniscus, is one of our two closest relatives. Many people don’t know that we are just as phylogenetically close to the bonobo as we are to the chimpanzee (and both are closer in relation to each other than to humans). New information regarding the bonobo – specifically their social and sexual behavior – has emerged recently which forces us to look at human behavior and human evolution in a new light.

Bonobos have a very curious and unique mechanism to navigate social organizations and dominance relationships. In their article The Other “Closest Living Relative,” Parish and de Waal investigate how sexual behavior helps to reinforce bonobo social structure. Observations have shown that dominance in bonobo populations, as compared to chimpanzee populations, is much more vague and less defined. It appears as though there is a certain degree of female dominance over males, or as some like to  define it “strategic male deference” (Parish and de Waal, 99). Females are in control of their social and reproduction in bonobo societies, and participate in more female – female association than the chimpanzees. Females will often engage in sexual encounters, specifically genital to genital rubbing, for a variety of reasons regarding this unique social structure.

Sexual encounters between females helps to maintain strong alliances between one another and reinforce dominance in a non-violent manner, which thus helps keep tabs, so to speak, on male behavior (Strier, 188). This practice of genital rubbing has a variety of other functions, such as facilitating female immigration into new communities, mediating competition for food, and the reconciliation after occasional acts of aggression. Strier does make a note that aggressive acts between bonobos is actually quite rare, considering the rate of violence in chimpanzees. Bonobos, in contrast to other species, specifically the chimpanzee, engage in all sorts of sexual behavior, not just heterosexual. There were many explicit photos of such processes, which I decided to spare you. So instead, here is a picture of a cute baby bonobo:

Investigation into other forms of social and sexual organization reveal many possible areas of contrast and comparison. There is much less competition between bonobos than with chimpanzees, especially in males. I wasn’t quite sure, from what I could glean from the article, whether this competition was strictly sexual or related to food selection as well. I did think it was interesting that testes size of bonobos was comparable to bonobos; we generally see increased testes sizes in populations with high sexual competition. Bonobos are also highly social compared to other forms of social organizations. Female bonobos while not in estrus remain highly social while female chimpanzees tend to isolate themselves to other females and clinging infants. Chimpanzees, according to Parish and de Waal, are evidently much more likely to avoid one another than encounter each other.

The conclusions that can be made from observing bonobo behavior regarding possible female dominance or “strategic male deference” have massive implications regarding bonobo / chimpanzee / human evolution. As I already mentioned, chimps and  bonobos share a last common ancestor with each other, and they both share a last common ancestor with humans. That being said, we can expect that bonobo behavior would be just as good of a predictor of human behavior as chimpanzee behavior. Hominid evolution, according to Parish and de Waal, has been dominated by the idea that humans evolved from creatures like  Savannah baboons, and was driven forward by male competition and dominance. Closer inspection of bonobo behavior strongly challenges this notion, and forces us to reconsider the behavior that lead us to become our beloved Homo sapiensOne of my favorite parts of the article, as I tend to consider myself a mild feminist, was the list of themes of sexual and social behavior that we must apply to our understanding of human evolution. That list included but is not limited to: female bonds, possible female dominance, female mating strategies, sharing of vegetation for food, flexible social patterns, and non-violent males (Parish and de Waal, 99).

These very same themes that I have just mentioned above must now be applied to how we study human sexual behavior. We have come to live in a society that seems to – for some reason – value male dominance, especially in sexual and economic relationships. In looking at the bonobos, it seems to stand that our typical male ancestor might not have been inherently violent and dominant. I particularly enjoyed the idea that female oriented and female respecting societies are not as far away as the lemurs, but are much closer than we initially expected.

Rock on female bonobos.