Over a decade ago I conducted a study with James King and Jack Berry on antecedents to psychopathology in chimpanzees. We used data that King had first collected in a study of personality in Chimps in 12 zoos, maintained under the auspices of the Jane Goodall Institute. Meaning the Chimps were living in as benign circumstances as zoos can provide, with efforts made to provide an interesting environment given the confines. The method used was to have zookeepers and volunteers who knew the Chimps well sit and observe them for hours and hours, and mark down how much they exhibited a variety of behaviors, derived from 43 specific personality attributes (used previously with people). This included behaviors like aggressiveness, friendliness, sociability, intelligence, and other obvious characteristics. King and his colleague Figueredo found the Chimps could be categorized on a scale very close to the most commonly used “Big Five Factor” personality scale used with people. There was one additional factor related to “Dominance” although I questioned its inclusion, as the attributes that went into it were also frequently found in “Extraversion,” one of the “big five factors.”
I began this new study by speaking at length to the zookeepers who had been part of the original study. Some of them had been with their “group” of Chimps for 15 years or longer. They really knew and spoke about their Chimps much as we speak of our children and family members. I heard stories, detailed fantastic stories of the Chimps behaviors. Some sounded quite screwy, along the lines of what, if it had been a person, we would have diagnosed her (yes it’s usually a “her”) as suffering from a “borderline personality disorder.” Others would –had they been people—been called “schizoid (personality disorder)” or “antisocial personality disorder” (we all know some of them, they take what they want, push to the front of the line, and don’t seem to worry whose feelings they hurt in the process). Others seemed to be quite normal, just ordinary, getting along with other Chimps kinds of behavior. After transcribing all of these extensive interviews, I read them over and over. Things just popped out at me, and I went to what was then our “diagnostic bible” the first version of the “DSM-IV” that psychiatrists and psychologists use to diagnose people with mental disorders. I started looking through disorders, characterized by “criteria” otherwise known as specific symptoms. I was limited to behavioral symptoms since I didn’t know what was in the Chimps’ minds, only how they behaved. My colleague Jack Berry joined me on this. Together we came up with five scales that were made up of “criteria” as laid out by the DSM-IV, and considered them antecedents to psychological problems we see in people. A few were the most commonly known psychological problems, like “depression” and “anxiety.” The others were “personality disorders (PD)” and specifically, “borderline PD”, “antisocial PD,” and “schizoid PD.” We then found the attributes from the original personality scales that fit into the characteristics or criteria for these disorders, thereby coming up with “antecedents to psychopathology in chimpanzee scales.”
What happened when we ran the statistics was amazing. Chimps I had thought were “schizoid” actually came out “schizoid” on our scales. One really mean girl, “Lila” sure enough showed up as “antisocial PD” on our scales. But most astounding was that we found that before adolescence, males and females were identical in proneness to depression. Sometime during adolescent however, the females zoomed ahead and became significantly more depressed than the males. What was so striking here was that they followed the exact pattern we have repeatedly found in people.
Our question then was –why did this happen (in Chimps or in our species)? Perhaps it was due to hormones and rising estrogen? Or was it because females were not as quick at metabolizing serotonin which left them more vulnerable. Biological considerations aside we wondered about the role of social environment – In other words - Is male dominance in any way related to the observed differences in proneness to depression between males and females. We wanted to look at Pygmy Chimps, better known as Bonobos. They’re the species that “makes love not war.” When they come upon a tree with ripe fruit, the first thing they do before jumping in –they all make love to one another. Males and females, males and males, females and females, they have a sex orgy. Then, apparently having reduced potentially competitive tension, they all enjoy the fruit together. Furthermore bonobos share often (so do chimps in their natural habitat, but not quite as much as Bonobos. Most striking -- in Bonobos culture, females are dominant because they stick closely together. If a male aggresses upon a female, the females gang up and go after the guy who flees as fast as he can. While there is infanticide among Chimps, there is no such thing with Bonobos. The women really stick together and thus their young are well protected, as well as one another. For all these years since we did this study, I’ve had this question –if we studied Bonobos in zoos, replicating the way we studied the Chimpanzees, would we find the females getting significantly more depressed than the males, around adolescence? Or would the female dominance protect them. Maybe the males would get more depressed. Is it social environment that leads to depression? We have no way to know. Frans de Waal, a world expert on Bonobos, told me he thought we’d be unable to find enough Bonobos to replicate the study, even if we looked at zoos world wide.
Then a few weeks ago I read a piece by Jason Goldman, a Scientific American blogger. He is summarizing research that demonstrates that Orangutan’s culture (which differs from group to group) is being passed on by ideas instead of by genetic differences, or some other physical or concrete environmental explanation. http://blogs.scientificamerican.com/thoughtful-animal/2012/12/20/is-orangutan-culture-made-of-ideas/
In Orangutans, just seeing a behavior before a child has the physical skills to actually do it, allows them to do it quite easily when they are old enough to develop the skills. But Orangs from a group where the behavior was never done so the children never saw it, have a much harder time learning it, when exposed to the behavior under different conditions, in a shelter where Orangutans from differing cultures are mixed together. Maybe the same is true of male or female dominance, and subsequently, maybe the onset of female depression in adolescence is part of a cultural package, made up of ideas carried from generation to generation. Could this possibly hold an answer to the mystery of the onset of adolescent depression in Chimpanzees and in our own species. Could the cultural habit of male dominance be something the young have to see, long before they can actually do it. Could the cultural habit of females sticking together and chasing off males who grew offensive, thereby establishing a female dominant culture be something youngsters just have to see, in order to later imitate the same pattern? I don’t have the answer but Goldman’s summary of this new research really made me wonder if male dominance is based on cultural ideas and cognitions and thereby possibly subject to change, albeit with effort.
The story of our Chimpanzee research is sadly an example of how the idea of male dominance holds power in our culture. Our study was presented at the APA in 2001, over a decade ago. Then a young alpha male joined King’s group. I’m not naming names. He grabbed the data, began to dominate the show, claimed he added some Chimps to the data, re-analyzed it and came up with the same results. But when I tried to publish our findings, he refused to give me the original data, or the data set to which he’d added. Feeling uneasy at publishing something based on a data set I was unable to review myself, presenting findings while being unable to re-analyze data on my own --well that seemed potentially unethical. Why would I be denied the data set, having been the principal investigator on the study? Must be the pervasive idea of male dominance. I withdrew the piece from the Journal to which I’d sent it. The new alpha male who had nothing to do with the original study is now getting a bigger and bigger name in animal and human personality. I accept it (almost), we live in a culture that’s still unfortunately male dominated at least in science. But I found Goldman’s review of the orangutan research a comfort. If social differences or culturally specific skills are related to cultural ideas, this thing we know as male dominance may all change in the future. Ideas may be far more malleable than something wired into our genetic material.
Gruber T., Singleton I. & van Schaik C. (2012). Sumatran Orangutans Differ in Their Cultural Knowledge but Not in Their Cognitive Abilities,Current Biology, 22 (23) 2231-2235. DOI: 10.1016/j.cub.2012.09.041
King JE, Figueredo AJ. (1997). The Five-Factor Model plus Dominance in chimpanzee personality. J Res Pers 31:257–271.
O'Connor, L. E., Berry, J. W., King, J., Landau, V., & Pedersen, A., (2001). Chimpanzee subjective well-being and psychopathology. Presented at American Psychological Association, August, 2001, San Francisco California.
De Waal, F. & Lanting, F. (1998). Bonobo: The forgotten Ape. Berkeley: U. California Press.