A new study of captive chimpanzees concludes that the personality traits of chimpanzees are almost identical to those of humans.
I asked psychologist Sam Gosling of the University of Texas at Austin what’s been learned from the study. Prof. Gosling didn’t take part in this particular research, but, as one of the first people to study personality in nonhuman animals, he has perhaps the best overview of personality in all kinds of animals, both human and nonhuman.
The authors of the new study, conducted at the Yerkes National Primate Research Center, identified five basic personality factors that combine differently in each individual chimpanzee: Dominance, Conscientiousness, Extraversion, Agreeableness and Intellect. This echoes the well-known Big Five model of the human personality, also known as the OCEAN model.
Michael Mountain: What do you mean when you talk about the various dimensions of personality?
Sam Gosling: When we talk about personality, we ask first how many personality dimensions there are. [Psychologist] Hans Eysenck once said there are three main dimensions to human personality: the introversion-extraversion domain; the neuroticism domain; [and a psychoticism domain].
You may also have heard of the famous Myers-Briggs Type Indicator, which says that humans can vary along each of four basic dimensions.
Most of the work in scientific psychology has settled on the idea that there are five dimensions – the Big Five or OCEAN model: your level of Openness to experience; your level of Conscientiousness; of Extraversion; of Agreeableness; and of Neuroticism.
So you have scores on all five dimensions, and you can be high, medium or low on each of these. And that’s what we mean by personality structure. We mean: How many dimensions are there? And how are they related to each other? The five main dimensions are generally unrelated to each other. So if I know your level of openness, that doesn’t mean I know anything at all about your level on any of the other four dimensions.
M.M.: So that makes for a very wide range of potential personality in any given person.
S.G.: Yes. And each of those dimensions is also very broad. When we talk about Extraversion, for example, this incorporates many other, narrower facets like your energy level, cheerfulness, gregariousness, talkativeness and dominance – those sorts of things, they’re all correlative, and so they all go to make up this broader domain of introversion-extraversion. And in general (but not always) those things like talkativeness and gregariousness tend to go together.
The Big Five model measures your level of Openness to new experiences; your level of Conscientiousness; of Extraversion; of Agreeableness; and of Neuroticism.The Big Five model relates to broad patterns of thinking, feeling and behaving. It doesn’t include things like our values, our goals, our identity and so on. If someone has a goal in life to achieve salvation or to become very wise, or they see themselves as wanting to save the world or whatever, that’s not part of the Big Five. The Big Five is just looking at behavioral traits and cognitive and emotional patterns as indicators of your basic personality.
Personality in Other Animals
M.M.: Some years ago, you started looking at other animals to see if you could begin to classify their personalities into particular dimensions, too?
S.G.: One of the early questions when we started was “Do other animals have personality?” And if so “What does that personality look like?”
So we began with the same questions: “How many dimensions do nonhuman animals have, and what are those dimensions?”
M.M.: So when this new study talks about chimpanzees having essentially the same personality traits as humans, does that mean they’re looking at them on all of these same five dimensions?
S.G.: Yes, and more. Because to say they have these five and any others, you have to search very broadly.
When I did my study of captive hyenas a long time ago, we found they had five dimensions. There was some overlap in these with the human Big Five, but some points of discrepancy, too. Virtually all species have something akin to the human extraversion and neuroticism dimensions.
And in another study that I wrote 15 years ago when I was just finishing graduate school, I tried to do a review of all the literature, saying OK, where do we see commonalities across species and where do we not see commonalities? And if you look at almost all the work that’s looked at personality structure and you take them all together, what they show is that virtually all species have something akin to the human Extraversion dimension. Extraversion at a broader level can really be thought of as individual differences in a tendency to approach positive things.
Almost all species also have an analog of what would be called in humans a Neuroticism dimension, and that would be the tendency to be sensitive to threats and danger.
So in almost all species, you find that they vary in their tendency to be sensitive to what can go right and be positive – things like food and mates, and foraging areas and territory and so on. And you find tendencies to be sensitive to things that can go wrong – things that can eat you.
What you see is that different combinations of those are adaptive in different circumstances. So, for example, you’ll find that with fish who live in a stream where there are predators present, it’s adaptive for them to be high on this dimension that’s like Neuroticism because then you will not get eaten, and you’ll be very sensitive to whether there are predators about. However in parts of the stream where there are not predators present, it’s maladaptive to be high on this Neuroticism dimension because you’ll constantly be worrying about things that aren’t there, so you won’t be taking advantage of eating and mating possibilities because you’re always on the lookout for these nonexistent dangers.
Personality in Chimpanzees
M.M.: So, going back then to the chimpanzee study.
S.G.: Well, when it comes to chimpanzees, there’s actually been a lot of other work done on this. Alex Weiss, for example, has been working on it for a long time. He’s been looking at apes and monkeys and he’s been saying that the bottom line is that chimpanzees seem to have all five of the human dimensions.
The one place that chimpanzees and humans really differ from other species is that there hasn’t been evidence of species other than humans and chimpanzees having the dimension of Conscientiousness. And that makes sense given what we know about the neural structure of conscientiousness, which is the advanced frontal lobe. It’s the ability to plan ahead, to inhibit one’s impulses, and to put something off until later. That’s really what the frontal lobe is about. And that very large frontal lobe is what’s different in humans from other animals. And chimpanzees have a pretty large frontal lobe compared to other animals, too.
M.M.: So, we might find the same thing in a few other animals, too, when we study their brains? Like you might see it in, say, elephants and some of the cetaceans if they have large frontal lobes? But that from what we know, you’re not going to find the Conscientiousness dimension in your cat at home?
S.G.: Probably. It turns out, though – and this is a complication –, that there’s something a bit different in cats and dogs. And that might be because we humans have put such high selection pressure on them that if we’re going to have creatures who live with us, there’s unusually large selection pressure for ones that are not going to do things that we don’t expect. So I think dogs and cats are probably a bit unlike other kinds of animals because of that specific selection pressure. And that selection pressure is much stronger – it’s artificial, just as we might select cows to have a high meat yield and be very docile.
M.M.: O.K., so back again to the chimpanzees.
S.G.: Yes, and one thing that Alex Weiss has shown for a long time is that they have this Dominance dimension, too, which is somewhat distinct. You don’t find that one in humans, where physical dominance isn’t so crucial anymore. With humans, it’s more other forms of dominance that might determine who gets ahead and who doesn’t. But the chimps have a very strong dominance dimension in addition to the Big Five.
Incidentally, hyenas have that Dominance dimension, too. They have a very strong social structure.
M.M.: Any other things in chimpanzees that are different from humans?
S.G.: Generally you’ll see an analog of Extraversion and an analog of Neuroticism. Often you’ll see a version of what in humans we call Agreeableness, but in animals it’s usually defined by the other pole: aggressiveness. And in other kinds of animals, Openness tends to be expressed in terms of curiosity and exploration and those sorts of things. But as you can imagine, that’s also linked to things like Extraversion because it’s to do with seeking new kinds of positive things.
M.M.: One of the things we’re interested in when it comes to seeking recognition for chimpanzees and some other animals as having certain fundamental legal rights, is being able to show that they’re cognitively complex, self-aware and autonomous.
S.G.: I don’t know how [this particular kind of study] relates to the self-awareness issue. I don’t think it speaks to that directly. But [the Conscientiousness dimension] does speak indirectly to self-awareness. Like, for example, in terms of the impulse to want to reach for the banana but to inhibit that impulse because I know there’s another chimpanzee nearby and if I reach for the banana, then that chimp will see that I have a stack of bananas over here and will come and take them form me. And the idea of being able to plan and think ahead. But I don’t know what the relation to self-awareness is in that domain.
M.M.: You’ve done quite a lot of work with dogs, too. Dogs have the distinct dimensions of extraversion, agreeableness and neuroticism.
S.G.: We’ve found that dogs have the distinct dimensions of Extraversion, Agreeableness and Neuroticism. But in dogs the dimensions of Openness and Conscientiousness seem to be fused together in a way. I think that with dogs, because they’re required to live in proximity to humans and also because we train them, there’s this fusing of Conscientiousness and Openness to a dimension that we called Trainability. It may not be a very good name for it, but that’s what we called it.
Do Any Animals Not Have a Personality?
M.M.: Have you come across any kinds of animals who don’t show personality?
S.G.: You know, it’s like all of those other things we [humans] put out there to distinguish ourselves from other animals. Animals don’t have them only as long as it takes until people go and take a look and see if they have them. It’s true of personality; it was true of emotions; it was true of thought; it was true of a moral sense. All of these things only last as long as people don’t look.
There’s recently a study that came out about spiders. There’s been work on fruit flies – they show individual differences, for example, in their tendency to get into fights or altercations with other fruit flies. You can test that by seeing if a fruit fly is more likely to become what we would call aggressive with another fruit fly and to see if they’ll do that across time, like today and tomorrow and the next day, and across context, like if they’ll do it in a mating context, a foraging context, and so on. Virtually every species that’s been looked at shows individual consistent differences in behavior. I would call that personality traits.
So it’s one of these things where virtually every species that’s been looked at shows individual consistent differences in behavior. Now, some people will say they don’t want to call that personality, but I would call it personality traits.
This has all really taken off in the last ten years since this work started to become popular in the field of animal behavior. So psychologists like me have been working on it; primatologists have been working on it; and lots of people in applied ethology, working with farmed animals of various sorts.
M.M.: I guess they all have different reasons for these studies – and they’re not always in the best interests of the animals!
S.G.: Once the animal behavior people got into it, or the behavioral ecologists, they are interested in evolutionary processes. And the applied ethologists want to find cows and sheep and other animals who have the right behavioral qualities for farming. And there’s a subset of people now who are using this in the context of wildlife management. They want to know, if we’re going to reintroduce wolves to a new place, how can we use personality to select which wolves get put into this park? And quite a lot of the people working in zoos are interested [in personality] in terms of which animals should be moved to a different zoo and which animals are going to make good exhibits. If you’re running a zoo, you don’t want to show an animal who’s likely to be hiding behind a rock all the time.
M.M.: That’s not what it was all about when you first got into the field.
S.G.: In fact, I’m beginning to get out of the whole field of animal personality now. When I started doing it, there was really nothing there. But now, it’s become such a big area that I can’t even keep up with the literature. There’s a publisher who’s actually starting a whole journal on animal personality.
M.M.: Thanks for explaining it all, Sam.