Consciousness Blog 07 February 2010
The study, carried out at the Department of Human Evolutionary Biology at Harvard University, compared aspects of the social behaviour of chimpanzees and less advanced bonobos.
Says lead study author Victoria Wobber: "Thus far, there has been no direct test of the hypothesis that certain aspects of behavior or cognition in adult bonobos represent developmentally delayed forms of the traits found in chimpanzees. We tested this hypothesis by comparing skills of semi-free-ranging infant, juvenile, and adult bonobos and chimpanzees in three feeding competition tasks, given the prediction that this area in particular differs between the two species."
Compared to chimpanzees, bonobos appear more peaceful and easygoing, retaining juvenile levels of play as adults, exhibiting low levels of aggression towards one another, and being much more likely than adult chimpanzees to share resources. "Bonobos took longer to develop the same skill level shown even among the youngest of the chimpanzees that were tested," says Wobber. "It seemed as if adult chimpanzees were able to exhibit more social restraint than adult bonobos. Taken together, our results indicate that these social and cognitive differences between these two closely related species result from evolutionary changes in brain development. Intriguingly, it has been suggested that the crucial cognitive adaptation of humans relative to other apes may be the accelerated development of social skills in infants. If we can understand the evolutionary processes by which developmental changes occurred in bonobos, perhaps inferences can be made about our own species' evolution."
These results seem to chime with the idea that it was the growing sophistication of the group that led to the achievements of humans. As a sweeping generalization, it must surely be true that relatively undeveloped groups, existing for mutual defence, warmth and predation, would have a high reliance on cooperative behaviours, while a more advanced group would develop a wider range of social behaviours, allowing the development of hierarchy, division of labour and the formation of flexible group strategies through discussion. Actually, the more basic group drives weren't sophisticated enough to act as a balance for more individually-oriented traits such as aggression and ambition, so that conformity also developed as an important kind of groupish glue for the human group.
Read more about conformity in Agent Human Chapter Eight by Michael Bell, The Con of Consciousness and the Illusion of Individuality.