In “Chimp, Bonobo Study Sheds Light on the Social Brain”, ScienceDaily reports (Apr. 5, 2011)
It’s been a puzzle why our two closest living primate relatives, chimpanzees and bonobos, have widely different social traits, despite belonging to the same genus. Now, a comparative analysis of their brains shows neuroanatomical differences that may be responsible for these behaviors, from the aggression more typical of chimpanzees to the social tolerance of bonobos.”What’s remarkable is that the data appears to match what we know about the human brain and behavior,” says Emory anthropologist James Rilling, who led the analysis. “The neural circuitry that mediates anxiety, empathy and the inhibition of aggression in humans is better developed in bonobos than in chimpanzees.”
[ … ]
Chimpanzees and bonobos diverged from a common ancestor with humans about six million years ago, and from each other just one-to-two million years ago. Despite this relatively brief separation in evolutionary terms, the two species exhibit significant differences in social behavior. Compared with chimpanzees, bonobos are more anxious, less aggressive, more socially tolerant, more playful, more sexual and perhaps more empathic.
“Chimpanzees tend to resolve conflict by using aggression, while bonobos are more likely to use behavioral mechanisms like sex and play to diffuse tension,” Rilling says. “The social behaviors of the two species mirror individual differences within the human population.”
Rilling heads Emory’s Laboratory for Darwinian Neuroscience, a leader in the use of non-invasive neuro-imaging technology to compare the neurobiology of humans and other primates.
Note that last comment: “The social behaviors of the two species mirror individual differences within the human population.”
The recent demand for new Darwinian language seems to mirror a new Darwinian way of processing information: Some people would have said,”The fact that certain types of behaviour appear to be innate in chimpanzees or bonobos, depending on the type, but vary by the individual is an example of a difference between chimpanzees and bonobos on the one hand and humans on the other.”