Human's Primate Cousins Also Pass Intelligence Through Their Genes
July 10, 2014

Human’s Primate Cousins Also Pass Intelligence Through Their Genes

Brett Smith for - Your Universe Online

Previous studies have shown that genetic factors for intelligence can be passed on in humans, but a new study shows that inherited intelligence also extends to our primate cousins – namely chimpanzees.

Published in the journal Current Biology, the study showed environmental factors in determining a chimp’s intelligence may be less important than previously thought.

"As is the case in humans, genes matter when it comes to cognitive abilities in chimpanzees," said study author William Hopkins, a primate expert at Emory University’s Yerkes National Primate Research Center. "It doesn't mean that they are the only factor determining cognitive abilities, but they cannot be ignored."

While the role of genes in human intellect has been examined for years, the new research is among the very first to tackle this type of heritability in nonhuman primates. Analyses have shown that human intelligence is passed down through genes, but social and ecological factors, such as education and socioeconomic status, also are involved and are somewhat mixed up with genetic factors. Chimpanzees, which are highly intelligent and genetically comparable to humans, do not have these further sociocultural impacts.

"Chimps offer a really simple way of thinking about how genes might influence intelligence without, in essence, the baggage of these other mechanisms that are confounded with genes in research on human intelligence," Hopkins said.

The study included 99 chimpanzees, ages 9 to 54, which completed 13 cognitive tasks made to test a wide variety of abilities. The team used a quantitative genetics evaluation to link the level of relatedness between the chimpanzees to their similarities or variances in performance on the various cognitive tests to ascertain if cognitive performance is passed down in chimpanzees.

"We wanted to see if we gave a sample of chimpanzees a large array of tasks," Hopkins said, "would we find essentially some organization in their abilities that made sense. The bottom line is that chimp intelligence looks somewhat like the structure of human intelligence."

The researcher’s findings indicated that differences in intellect may have come about in the common ancestor of humans and chimpanzees about 5 million years ago. The team speculated that their work could eventually lead to the discovery of intelligence genes in primates.

"What specific genes underlie the observed individual differences in cognition is not clear, but pursuing this question may lead to candidate genes that changed in human evolution and allowed for the emergence of some human-specific specializations in cognition," Hopkins says. "It is also intriguing to consider what changes in cortical organization might be associated with individual differences in cognition and whether common genes might explain their common variance."

The primate expert said he wants to continue the investigation with a bigger sample size. He would also like to engage in analyses to figure out which genes are included in intelligence and various cognitive abilities and how genes are associated with variation in the organization of the brain.

Hopkins said he also would like to find out which genes changed in human progression that allowed humans to have such superior intelligence.