Our Human Spark crew traveled to the Yerkes National Primate Research Center at Emory University to meet with the scientists – and the chimps! – who work there. Vicky Horner is a psychologist who explained to Alan Alda her work on chimpanzee cultural transmission. Here she shares some of her thoughts on her field of research and what it can tell us about the human spark.
by Vicky Horner, Living Links Center, Emory University
To many people, the words “culture” and “chimpanzee” don’t seem to go together. In fact, apart from starting with the same letter, they seem to have little connection at all. It’s therefore always slightly awkward when I have to explain what I do for a living to someone I don’t know very well. When I tell them that I am a psychologist, but that I work with chimpanzees and study their cultural behavior, I get the distinct impression that some folks think perhaps it is me, and not the chimps, that needs a psychologist!
The looks of surprise and confusion come from the fact that for many people the notion of culture equates with the fine arts, a night at the opera, or a refined palate for expensive wine. The idea of a chimpanzee at the opera sipping on a nice glass of chardonnay is pretty comical, even to me. We can all think of lots of examples of cultural differences between groups of people, but actually defining it in biological terms is a little more difficult. Psychologists, anthropologists and biologists have been arguing about culture for decades, and although we still don’t agree, we are getting a little closer to a definition that keeps most people happy. In order to understand culture, and more importantly to understand the evolution of our own cultural abilities, we need to stop getting caught up in examples of our cultural behavior and focus more on how cultural differences develop in the first place. At the fundamental level, culture is simply a collection of learned behaviors that have been passed on from one generation to the next, such as using chopsticks or knives and forks. For many years culture has been regarded as the hallmark of our species, the ‘human spark’ that separates us from other animals. However, before we can make claims about our own uniqueness, we need to check for similar sparks in other animals, starting with our closest living relatives, the chimpanzees, with whom we share a common ancestor and about 99 percent of our DNA.
A few years ago, a group of scientists working in Africa got together to compare the behavior of the chimpanzees at their field sites. What they found was rather surprising. At every site, the chimpanzees displayed a totally different pattern of behavior, such as how they use tools and weapons. These differences were not easily explained by differences in habitat or genetics. The scientists therefore thought that perhaps these differences represented chimpanzee cultures, and arose because each group had invented different solutions to similar problems (like dipping for ants with long sticks or short sticks), and that these behaviors were maintained over generations by learning from one another.
However, it is very difficult to study culture and learning in the forest because there are so many variables, so at the Living Links Center we study chimpanzee culture in a more controlled captive environment. We study two social groups of chimpanzees who live in large indoor-outdoor enclosures with climbing structures, grass and toys. We train one chimpanzee in each group to act as an “inventor” who solves a food puzzle (like how to get the banana out of the box with a stick) in one of two different ways. We then track if and how each new behavior spreads within the groups. These studies are important because they show us that chimpanzees have the brains for culture; they can learn and maintain new behaviors accurately enough to support the reports of culture from the wild. I am not claiming that there is no difference between going out to a Chinese restaurant to practice your chopstick skills and staying home to fish for termites in the back yard, but the fundamental psychological mechanism and the evolutionary driving force behind the two is the same.
So what does all this mean for the human spark? To me there is no single spark that separates us from chimpanzees; we are intricately connected by our common ancestry. The differences between us arise from thousands of tiny differences in the frequency and contexts in which we do things. For example, we imitate one another constantly; chimpanzees imitate each other sometimes. We take other people’s perspectives on situations frequently; chimpanzees take another’s perspective sometimes. We empathize frequently, they empathize in some contexts. It is all of these little tweaks here and there that make up the human spark.
On a final note, I’d like to emphasize the importance of not falling into the trap of thinking that we are the ultimate and desirable endpoint of evolution. Chimpanzees and humans have both been evolving form our common ancestor for the last 5 million years. They may not be at the opera, but chimpanzee culture is remarkable in comparison to other species. We also have a habit of measuring their abilities against our own human checklist in the quest for the human spark. But what would happen if we measured ourselves on a chimpanzee checklist; would we find a “chimpanzee spark”? How do you measure up to this five-year-old chimpanzee?