For the last 20 years, Dorothy Cheney and Robert Seyfarth have focused their research on some 75 wild baboons in Botswana's Moremi Game Reserve. They've uncovered a wealth of information about the primates' social behavior, including that — like humans — those who are more socially successful tend to live longer, healthier lives and have better reproductive success. Most recently, the husband-and-wife team linked female baboons' personalities to that all-important social success. In other words, nice baboons actually do finish first. We spoke to Cheney and Seyfarth — both professors at the University of Pennsylvania — about their innovative research.
You began studying this group of free-ranging baboons in Botswana in 1992. What led you to that particular place at that particular time?
Robert Seyfarth: We were just finishing an 11-year study of vervet monkeys in Kenya. A colleague of ours had been watching these baboons for several years and was getting ready to retire. He was looking for someone who might be interested in continuing the project so we jumped in.
Dorothy Cheney: The main reason for choosing baboons is that they live in these very large, social groups — up to 26 females and 12 adult males and their offspring. You can look at these very diverse types of social relationships and interactions in ways that you'd be more limited with in a small social group. This was also a unique opportunity to work with animals who are living in the wild, so you're actually watching animals in the context in which their behavior presumably evolved in the first place.
Tell me about your most recent discovery regarding baboons' personalities and social success.
DC: You have to go back a couple years to some of our previous findings. We found, somewhat to our surprise, that female baboons who have very close social bonds with other females have offspring that survive at higher rates for longer and they also live longer themselves.
RS: Female baboons stay in groups in which they were born all their lives; the males migrate. The females assume dominance ranks similar to their mothers. When you're looking at a baboon group you're really looking at a dominance hierarchy of families. If it's the ability to form social bonds that is the major factor influencing how successful you are as a female, and if you can't explain that ability by rank alone or the presence of kin, there must be something else. It was the quest to identify and locate that 'something else' that led us into this analysis of individual differences in what you could call personality.
DC: We found that the 'nice' females, for lack of a better word, tend to have closer social bonds with others and that the females who are loners tend to have much weaker bonds and also higher stress levels.
What makes a baboon 'nice'?
DC: The so-called 'nice' females tended to be alone less often, they tended to be less aggressive, very friendly to others, and they grunted — which is kind of like conversation in humans — to others often, particularly low-ranking females.
Have similar studies been done with other animals?
DC: The result that a close social bond with members of the same sex is adaptive is now being shown in huge varieties of animals in addition, of course, to humans. Recently it's been shown that female rats and mice and dolphins and horses who have close bonds with each other tend to have higher offspring survival and lower stress levels.
Can you talk more about the similarities to human studies?
RS: These results replicate in baboons some of the most interesting findings that have been coming out of work on human longevity. If you look at the book The Longevity Project, for example, it turns out it's not necessarily wealth or education that predict who lives longest. A lot of it is predicted by who has a strong supportive network of social relationships — of friends. You might say, Well gee, that happens only in humans because we have culture and language and so on. But in fact the same phenomenon emerges in baboons. It looks like we have a deep-seated benefit from being able to form close relationships with others, as do elephants and hyenas and chimpanzees — many animals.
DC: This is all quite new.
Which part is new? Looking at animals' personalities?
DC: People have tried to look at personalities in animals using human designations like inquisitiveness and conscientiousness in the past. That doesn't necessarily translate easily into animals' actual behavior. The whole idea of trying to tie variation in personality to fitness is brand-new. It's intriguing because you can't necessarily explain fitness entirely in terms of competitive ability, for example. The fact that we're finding these results in animals that are surprisingly similar to those found in humans suggests, to us anyway, that this is an ancient benefit — an ancient trait that's been under strong evolutionary selective pressure for probably millions and millions of years and doesn't depend only on culture and language and the human attributes we think are unique to human friendship.
RS: We've been doing quite a number of experiments to examine the nature of social knowledge in baboons. It looks like they really do know about each other's family relationships and they make use of this often in their daily lives. These categories of rank and kinship are intricately involved in the animals' social life and tell us a lot about their cognition, about what they know about each other. We're beginning to understand that one of the most challenging features of a primate's environment is other primates. One of the most interesting aspects of their cognition and their intelligence is what they know about each other.
DC: We find that monkeys are excellent at recognizing who associates with whom and who outranks whom. They use this knowledge when soliciting alliance partners or reconciling with their opponents. The idea is that if you're going to live in a complex social group with many other individuals you have to know not only about your own social relationships but also about the social relationships of others. Humans do this all the time. This is why we have magazines like People and Us Weekly — because we're all interested in other people's individual relationships. Monkeys seem to be the same.
What do you hope to study going forward?
RS: The work we've talked about so far focuses entirely on females and their interactions with other females. Right now we're applying the same techniques of analysis to females and their relations with males and males and their relationships with each other. This is potentially interesting because females and males live very different lives with very different selective pressures imposed on them. Males leave the group where they were born when they reach adult size and they really tend to live in groups without their close kin for virtually all of their lives. What does that say about their kinds of relationships? Can we find interesting individual differences in personality among the males? With females, if a female is nice to other females, does that also mean she's nice to males? So that's what we're looking at now.
Can you sum up why this research is important?
RS: Given the fact that humans have these striking individual differences in personality and that the differences in personality seem to have major implications for their survival and happiness and performance in school, it would be very nice to know where these come from. Are they completely unique to humans? Or is it possible that we can find comparable individual differences and even personalities in animals — and if so, do they give us any hint about why the individual differences we find in humans have evolved? There ought to be some sort of explanation for them.
There are a lot of parallels here with the way human individuals interact with the society into which they're born, and we have a chance to study it in a simpler but equally interesting case among baboons.
From top: Robert Seyfarth; baboons in the Botswana reserve; Dorothy Cheney. All photos by Dorothy Cheney.