Chimpanzees and other great apes are known for their intelligence: They can learn words, play with objects, and even seem to mourn the deaths of their friends. But just as for humans, cognitive abilities vary from one animal to the next.
Now, in one of the largest studies ever conducted on chimp cognition, researchers report that those individual differences are due in no small part to genetic makeup. The study appears Thursday in Current Biology.
Genes determine about half of the variability in chimp intelligence and environmental factors the other half, according to primatologist William Hopkins, of the Yerkes National Primate Research Center in Atlanta, Georgia, and colleagues.
Research on animal learning has been focused almost entirely on the contribution from the environment. For most of the 20th century, scientists held that animals were like robots, behaving in predictable ways based only on environmental cues, such as reward and punishment. This new study adds to growing evidence that animals are not passive machines but rather are sharp, active thinkers.
Studies of humans have produced similar estimates to the primate study, suggesting that intelligence is approximately 50 percent heritable. But human development is heavily influenced by cultural factors, such as formal education systems, and so nature and nurture are difficult to tease apart, Hopkins said.
Being one of the closest relatives of humans, he said, “chimps offer a simpler way to think about that question.”