Primate Social Cognition

The Following is a brief summary of “Understanding Primate Brain Evolution” by R.I.M Dunbar and Susan Shultz. The researcher begin by describing the original social brain hypothesis, which was used to explain why primates have larger brains compared to their body size when compared to other vertebrates. Throughout this explanation they state that the limiting factor for research into the limit of the social brain hypothesis is the small amount of attempts to to evaluate if the relationship between brain size and group size is truly bound to these variables. Their points to prove throughout the research were to:

  1. confirm the original findings hold up to not only primates but a wider perspective across the mammalian spectrum, and
  2. View brain evolution within a broader perspective.

As the social brain hypothesis was extensively tested on primates, research from Perez-Barberia & Gordon (2005) and Shultz & Dunbar (2006) have been able to show that social species have a larger brain. It was also considered that habitat may play a part as those in mixed habitats had a larger brain than that of the mammals in the open or closed habitat. Dunbar and Shultz stated, “that the two traits are under tightly coupled selection; changes in one trait (sociality) are only possible if they are associated with changes in the other trait (brain size)”

Perez-Barberia’s analysis provided a hand for lagging evolution throughout the 3 different habitats but did not find consistent pathways for these findings. Thus providing a “flexibility” or lack of cohesion within the groups.

To evaluate a in greater depth the relationship between brain size and association  between species-specific behavioral, ecological, life-history characteristics, etc to the social brain hypothesis, Shultz & Dunbar created an evaluation in which a three-step analysis.

  1. the univariate analyses in which the different behavioral and ecological traits are measured with how much they associate with measures of the brain size.
  2. the use of general linear models to test alternative models of the characteristics and how they relate to both brain size and being social.
  3. They built a test a path model to integrate life history, ecology and social complexity as causes and consequences of brain size.

With this test they found that the brain volume correlates with the sociality of the vertebrates. In primates particularly, it is a strong relationship to the size of the social group but more importantly the act of “social play”.

Along with the size of the brain it was found that the neocortex in some cases also appeared larger within primates. Pointing to the importance of the frontal lobe.

With this information discovered, they have a very small look as to how the brain produces these effects and suggested that as brain size increases, a disproportioned computational power becomes available. Thus allowing for increasingly sophistication in social behavior of the primate or animal in question.

The experiment as a whole is a very grand idea and gave one a closer insight into the wonders of the brain and how ones surrounding can affect characteristics like sociality or brain size. I would want to look more into the genetic mechanics behind this or if they in fact play a part big or small into the outcome of the brain size, learning, or intelligence level.

—A.A

Chapter 3

The following is a brief summary of chapter 3 of the book “The Encultured Brain: An Introduction to Neuroanthropology” edited by Daniel H. Lende and Greg Downey. The title of the chapter is “Primate Social Cognition, Human Evolution, and Niche Construction: A Core Context for Neuroanthropology.” It was written by Catherine C. MacKinnon and Augustine Fuentes. The authors begin their discussion with the background of primatology. In the 1930s up through the 1950s researchers were focused on studies of social behavior and ecology of the nonhuman primates. In 1951, Sherwood Washburn called for a “new physical anthropology” in which research would integrate laboratory and field studies, examine comparative anatomy and functional morphology, and describe the links between ecology and behavior. In the 1960s and the 1970s fieldwork was conducted with chimpanzees, mountain gorillas, and orangutans by researchers such as Jane Goodall, Diane Fosse, and Birute Galdikas. In the field of psychology, Harry Harlow conducted his notorious experiments on the significance of primate mother – infant attachment and social bonding. In the 1970s and the 1980s the focus turned to social biology and evolutionary psychology. Here researchers focused on how human brains gained cognitive components that evolved to solve the reproductive problems faced by our hunter gatherer ancestors.

Primates, including humans, share various general characteristics including; prehensile hands and feet, a reliance on visual and tactile sensory pathways, extended periods of infant dependency and development, and significantly enlarged brain to body size ratios. The expansion of the visual system is seen as being tied to sociality. Primates must be able to read complex social signals and their emotional content. Among primates there is a strong tendency towards sociality and group living. Physical and emotional bonding and social attachment have been determined to be crucial for the healthy development of the central nervous system. Primates employ color vision to help find foods, use their memory in the spatial mapping of resources, and communicate about food sources as well as predators. The authors suggest that our brain and our visual system selectively focus on information which can protect us from potentially dangerous individuals or situations. Advanced cognitive structures allow primates to display a great range of plasticity in foraging behavior and living environments.

Primates also engage in niche construction, which can be defined as the modification of the functional relationship between organisms and their environment by actively changing one or more of the factors in that environment. Through this process primates have significant effects on their environment which then affect their population. For example, responses to the energetic cost of increasing brain size and extended period of child rearing in genus Homo included more cooperation between group members, an increase in the complexity of communication, and increased effectiveness at avoiding predators and an expansion of the types of environments in which they live. This is also seen in other primate species. For example, female capuchins keep track of and maintain large social networks over the course of their lifetimes. Social organization characterized by fission-fusion groups and subgroups common among chimpanzees is another example. It is been observed that some members negotiate rank through aggression while others rely on coalition partners and social bonding. The authors conclude that a highly evolved social cognition is required to keep track of the social networks. The authors suggest that social network analysis can be a fruitful method allowing researchers to examine types of interactions among individuals in a social group. Social network analysis allows for the examination of complex patterns in which primates organize themselves socially.

Primates also share the characteristic of an extended period of dependency after birth. The level of social complexity is correlated to increased sizes of neo-cortices. Among the primates, humans have the least mature brain at birth followed by a period of rapid brain growth, influenced by an environment rich in social stimuli. It is also suggested that an increased consumption of animal protein also brought hominids in close competition with carnivores also resulting in an increase in brain size.

The cultural intelligence hypothesis suggests that humans have a species specific set of social cognitive skills for participating in and exchanging knowledge through particularly complex cultural groups. Among primates, research has found cooperative and altruistic behavior in certain situations with varying results. Chimps have been found that while in adjoining cages they will sometimes give tokens which produce a food reward for both of the animals. It is also been shown in laboratory research that capuchins may value equitable behavior. In conclusion, research suggests that primates display extensive plasticity in sociality and cognitive functioning which results in increasing brain size, social complexity, and evolutionary success via biosocial niche construction.

http://www.exploratorium.edu/evidence/

–G.B

18 thoughts on “Primate Social Cognition”

  1. The idea of niche construction seems to me commonsensical. Initially, science aimed to describe the diversity we see all around. Research then seemed to shift explaining how we ended up with so much diversity, i.e. change over time. It is refreshing to see that science has entered another paradigm, one in which spheres of influence are not unilineal. This shift is also evidenced in Physical Anthropology as we move towards a more biocultural approach. Niche construction, a classic example of a positive feedback loop, helps explain why, once increasing, primate brain size and sociality kept increasing. It is perhaps easier to see how a positive feedback system functions in comparison to identifying what initiated the system in the first place. In the question of what came first, the chicken or the egg, should we find comfort in the fact that eggs are laid by chickens and to be a chicken you must both hatch from and lay an egg? Alas, Science is a search for clarity. It is with this in mind that scientists will continue striving to untangle the relationships between environment, physiology, and psychology in the hope of understanding how we came to be the big-brained social butterflies we are today.
    Speaking of such optimistic scientists, I appreciated Dunbar and Shultz’s article “Understanding Primate Brain Evolution.” Not only did they highlight the simplistic thinking of research which holds fast to a straight-forward causal relationship between various environmental factors and brain size, Dunbar and Shultz were also very careful in their data analysis. Firstly, they made sure to test previous assumptions that related various ecological factors to primate brain size. As their analysis proceeded along three stages, Dunbar and Shultz increasingly added complexity to the system, ending up with an integrated model of the phenomena of increased brain size and sociality. While the neurological details remain a bit hazy, this kind of research is a good start in the fight for clarity.

    1. Aaron A. Sandel, Evan L. MacLean, and Brian Hare have sought their own clarity in regards to primate cognitive evolution. Their 2011 article “Evidence from four lemur species that ringtailed lemur social cognition converges with that of haplorhine primates” explores the sociality of lemurs through the study of their ability to read social cues in scenarios related to food competition. While haplorhines have been shown to be very adept at utilizing social cues to their advantage when locked in competition over food, this behavior has not been documented for strepsirrhines. This research found that out of four lemur species, only ringtailed lemurs passed up food within a competitors view in favor of food outside the range of a competitor’s gaze a significant number of the times during the test. Ringtailed lemurs also showed more alertness when presented with a noncompetitive gaze-following task: ringtailed lemurs looked up more often when an experimenter peered into the enclosure than when the experimenter’s gaze was averted.

      Sandel, MacLean, and Hare conclude that the ability to recognized social cues and act on them advantageously was not likely a trait held by the last common ancestor of haplorhines and strepsirrhines. Ocam’s Razor suggests that ringtailed lemurs evolved this trait independently. Ringtailed lemurs’ high cognitive abilities and group complexity also provide evidence for the correlation of social cognition and complex social systems. If indeed natural selection of sociality was spurred on by the social bonding of groups (as Byrne and Whiten (1988) and Dunbar (1992,1998) propose), then this research seems to lend support to the social intelligence theory (though Sandel, MacLean, and Hare rightly acknowledge the complexity of this matter).

      I agree with the authors that the study of cognition would be greatly benefited by a phylogenetic approach. As this research shows, not all lemur species were created equal. The interspecies diversity found in Primates is too great to be glossed over.
      -C.M

    2. A big part of understanding humans is trying to decipher if we are special, how we are special, and to what degree are we special as a species. This is something that we have come back to again and again in our class discussions. On the one hand, humans have a long evolutionary history of being subject to the same pressures as other species. On the other hand, we have a complex culture which has brought us “out of the wild” so to speak. For now, this is a man’s world. Part of how we reconcile our place in this world is through understanding our closest living relatives: other primates.

      Just last week we came back to the cultural intelligence hypothesis. To what extent can primates cooperate or think abstractly? Right now there is no conclusive evidence that they do either. Scientists can observe their actions, but it is impossible to understand the thought processes motivating actions and interactions. I think the answer might be found in devising a multitude of scenarios that may be used to test social interactions and social play and testing multiple primate species. Until someone builds a contraption that translates animal vocalization or thought to human language, we can look at social behavior and social play as well as total brain volume to get a sense of what is going on. The case may not be rock solid, but a load of circumstantial evidence does have weight. One thing is for sure. While most scientists no longer place humans, who were made in God’s image, on a pedestal, it is equally inaccurate to say that all creatures were created equal. As natural selection can attest to, that statement is simply not true.

  2. Quite often in our mainstream biology classes we normally and sometimes altogether lose sight of the role of sociality in development. I personally would hardly have given a thought to the role of sociality in the development of the brain, let alone that brain size and social complexity may have coevolved if I were not an anthropology major. I appreciated Dunbar and Schultz’s careful explanation of the data and the relationships between neocortex size and other variables. Something else I found interesting from this article that was reiterated in Ch.3 of “The Encultured Brain” was the idea that social complexity doesn’t necessarily mean size, although it can include that, it means all the complex interactions of a social group that force a brain to be suited to such an environment. The other thing from Ch. 3 that really stayed with me was the idea that the socially complex behavior within social groups can act as a force on the species’ niche. I was always taught that a niche is shaped by outside environmental and ecological factors, certainly beyond the control of the species, but that way of thinking seems at least partially untrue.

  3. A few things piqued my interest in the MacKinnon and Fuentes paper. Immediately the concept of evolutionary psychology was brought up and several topics of study were mentioned specifically (such as the evolutionary development of morality), so I was a bit disappointed when that topic wasn’t actually discussed. I understand the paper was going in a different direction, but I still want to pout for a second anyway. Okay, done. The stated focus of the paper was to demonstrate the importance of primate studies in neuroanthropology, and to that goal the paper did a pretty decent job: It offered similarities as well as differences between primates and humans and explained how these affect development in both through a mostly neuroscience context). Some parts were definitely less interesting to me than others (for example, my mind got a bit wandery at and I ended up just glossing over the descriptions of ranking and relationships across three or four different primate species). I appreciated the reminder on page 76 and continuing to 77 that it’s pretty fantastic that as humans we communicate across both SPACE and TIME in a way no other species does. Often I forget to be amazed by the little things and sometimes science reminds me to be. The third focus of the paper (C: Cognition and Sociality) appealed to me most. . The authors pointed out the complicated interplay between social environment, biology, and behavior and how they all feedback into each other, and while these may appear common sense, it’s still something I hadn’t been forced to consider before and appreciated it. Neural development and neurochemistry were discussed in more detail in this section, which is more my cup of (N)T. The direct comparison between the prefrontal cortext growth in infant chimps and infant humans and how the difference in white matter may affect language and social interactions interested me much more than social structures and was more what I expected all along from the article. The comparisons of weaning time and infant dependency were also pretty cool and left me fairly curious about the matter and the interplay between culture and environment and biology (for example: what we find culturally acceptable for weaning of humans (especially since it varies so much across cultures) and when a child should be weaned from a biological basis). Of the sections in the paper, this last one was the one that did the best job of convincing me of the paper’s original goal of expressing the importance of studying neuroscience in primates in relation to neuroanthropology.

  4. One of the main things that interested me about the readings involved the part in chapter 3 that discussed the neocortex. I found it interesting that it is sufficient for none of the cognitive functions that it is necessary for. It was also interesting to me that the neocortex is much larger in primates compared to other mammals. The author states that this “tells us little about cognitive ability” in these primate species, which is why it has been the subject of many studies. I think that this was one of the more interesting things from the chapter because there are still so many unknowns about the brain and the human body in general. It would be interesting to find out if the neocortex was involved in more than we thought it was, which might account for its size difference in these primate species.

  5. According to the review, primates have showed extensive plasticity in socially and cognitive functioning, which results in, a change in brain size, social complexity, and evolutionary success.
    After reading this summary, I thought to myself, if a primate’s brain, or a human’s brain, can change its entire brain structure from social experience, I wonder how social networking, for example, twitter, facebook, or even the internet in general, has changed the structure on a human’s brain.
    I have noticed that more and more people suffer from depression and addiction to drugs, along with many others mental issues, I wonder, if the increase in social complexity in our culture has changed something in the human mind or makeup of the brain.

    1. In response to how social networking, i.e.,twitter, facebook, or even the internet in general, has changed the structure on a human’s brain, there is a great article by Eric Michael Johnson called “Social Networks Matter: Friends Increase the Size of Your Brain” here is the Link link Its a really good read and talks about research done by Dunbar.

  6. Our knowledge of studying primates other than humans is valuable seeing that we parallel so many features regarding social complexities and cortical abilities. First and foremost, despite the copious amounts of research on primate neural function, we still are not quite sure about the intricacies regarding the brain. I also found it interesting that compared to primates, carnivores possess a less extensive networking of axons and neural connections in the brain. I had no idea that humans had the least mature brain at birth amongst the other primates, and I had no idea that other primates could see in color. Although I am quite aware that we humans are primates, I assumed that due to our higher order of thinking and neural connections that our need for color vision would be greater than other primates. In addition, I found that the Dunbar and Shultz article was very enlightening. I hope we will discuss their results and background information a bit more extensively in class.

  7. I feel like most of chapter three focused on the neocortex, but I found the evolution of mostly visual sensory pathways to be especially interesting, with regards to humans and primates becoming social beings. Being able to read microexpressions and social cues from other individuals is critical to being able function in a group environment.

  8. My major take away from the review centered around the neocortex being found to be larger in some primates. A large brain is a very impressive feat but said brain must be put in some sort of context to truly appreciate the cognitive evolution of a species. As we mentioned in class, a whale has a very large brain but in comparison to body size it is less impressive. When compared to our relative size our cranial capacity implies intelligence. The idea of the neocortex raises so me questions for me regarding a piece of our own evolutionary history. I believe it was the Neanderthal that had a larger cranial capacity than we did and yet they died out where we survived. Could a better developed frontal lobe have played a role?

  9. When reading, Michael Johnson’s article, Social Networks Matter: Friends increase the size of your Brain, he asks a question at the end of that article. Johnson’s question was: Could it be that online technology has allowed some individuals to express (and expand) a social behavior that emerged for other adaptive reasons but which has been underutilized until now?
    After reading that article, I went on to the Exploratorium website that stated, the gene for speech and language evolved relatively fast in humans. This, in turn, increased our chances of survival and reproduction, and advanced our ability for the use of tools and how to solve social problems.
    After reviewing this material, I begin to think, sense technology is advancing so rapidly, which is increasing human intelligence and brain size, according to Michael Johnson, and that the gene for language and speech evolved so quickly in the past, could we be evolving too quickly? Which, in turn, could have some unexpected effects on how the brain is wired, meaning, for instance, people who have ADHA? People who have ADHA, or Attention Deficit Hyperactivity disorder, according to WebMD, are people, who are overactive, impulsive, and inattentive. Could these characteristics be better suited for our hunter-gatherers ancestors instead of child or adult who sits at a job or in a classroom every day?
    According to Brian Krans in his article, Were Hyperactive Hunter-Gatherers better adapted than their peers? Krans talks about an ADHA study that was conducted at Northwestern University in 2008, which examined two tribal groups in Kenya. Group one, who were still nomadic, and Group two, who were settled into villages. Krans claims that what was discovered was that the members of the nomadic tribe, with ADHA, were better nourished because they still hunted for their food, than those without ADHA, who still hunted for food. Group two, for those who were settled into villages, and had ADHA, had more difficulty in the classroom than those without ADHA.
    Given this info, I began to think, maybe because our language and communication skills, such as social networking, and the internet in general, are growing at a massive rate and that speech and language skills develop so rapidly in humans, it may be causing issues with the way humans interact with another and their surroundings. Maybe ADHA is only a disorder when considering social surroundings or culture.

  10. Recently, I read an article that describes how only 6 groups of animals are able to participate in vocal learning, which is the ability to learn and reproduce specific sounds. These animals include parrots, songbirds, hummingbirds, humans, bats, and cetaceans. I became interested in the idea of vocal learning after I read an article stating that a captive orca was able to “learn” dolphin. I had not known that different species could potentially learn each other’s languages. I wonder if this concept could be applied to the different species of primates. Primates have a complex social structure, and the foundation of society is the ability to communicate. I wonder if any primate species have evolved with the ability to learn the language of other primate species, to enable communication. This seems likely to me. I just have this picture in my mind of delegates from different primate groups hashing out territorial agreements. While I do not think the societal structure of primates is quite this complex, it makes me wonder if it is down the evolutionary road.

    http://jarvislab.net/Publications/Evo_Vocal_Brain_Structures.pdf

  11. Thing part of our discussion that interested me most involved one of the videos shown in class of a monkey that was used in experiments. The monkey was given the option of going to two different fake mother monkeys, one of which had food and the other one was merely one that could be used for comfort. I found it interesting that the monkey chose to go to the “mother monkey” that would offer him comfort when he was scared and clung to her. I suppose that I do not usually think of monkeys having an emotional capacity such as that because they are animals, even though I would expect this from my dog at home, which is even more interesting to me. I suppose that my thinking of animals such as monkeys as “wild,” despite their habitats has shaped my thinking of how they are supposed to react in such situations, and I did not expect that they would react in such a “human” way.

  12. I was originally going to comment on something else but after I saw this video and what I thought could be an example of a group of people and how they interacted with their environment to change it and their role in it I had to write about it. It’s a PBS segment (I’ll attach it at the end of my comment) about the Mosuo people in southwest China and how their lives have and are changing in an example of niche construction. They are a traditionally matriarchal and matrilineal society with what are called “walking marriages”. These marriages do not have husbands or wives and the couples do not live together. Both men and women remain with their maternal family for their entire lives with their uncles as their father figures. The men only visit the women they have relationships with at their homes at nights.
    Where niche construction comes in is that in some villages tourism has become a major source, sometimes the main source of income, for the entire village and the families. In the past most of the Mosuo families engaged in agriculture of some type. However, many Han Chinese have become interested in their way of life and come to their village to stay, visit, and watch them dance. The Mosuo have adjusted their lives accordingly. They have built hotels and provide entertainment in the form of dance frequently. While this has been extremely beneficial in many ways it has also negatively impacted them in ways they could not have anticipated. The increased interaction with outsiders was changing the social dynamics of the village and possibly their marriage practices. Unfortunately, one woman explained that before all the tourism they could drink out of the lake but it was now too polluted so they sought water elsewhere.

  13. The existence of the social brain hypothesis makes me wonder about the connection the mental disorders. Schizophrenia is the first to come to mind because of how it can be exacerbated due to lack of social interaction, i.e. solitary confinement. It’s interesting to see how the brain gets larger as sociality increases, but problems can arise when social networks are cut. It makes one wonder which influenced the development of the other.

  14. The classic monkey experiment regarding the soft, comfort mother figure versus the cold, metallic mother figure in the fear experiment in class still remains clear in my mind. I find it interesting that at such a young age, these monkeys are able to emote in a way that we don’t normally attribute to other animals. How does this experiment translate to other situations? For instance, with the rise of anxiety and depression in the United States (a fear trigger) many people turn to the comfort of food (mimicking that soft, comforting “mother” robot from the video). In turn, there has been a rise in obesity and cardiovascular disease. I recently read an article (from the Neuroanthropology Interest Group on Facebook, actually…) about how procrastination gives us a comforting experience amongst a fearful stimulus. It’s a way of distracting the brain. Primate social cognition provides us so much insight into the brains of our primate relatives as well as ourselves. There is so much research in this field just waiting to be touched. Here’s the article: http://www.vox.com/2014/12/8/7352833/procrastination-psychology-help-stop

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