uit: Bonobos and the Child-Like Joy of Sharing
Brian Hare and colleagues have just released a video (see below) showing a bonobo juvenile voluntarily helping another individual out of their cage to share a few delicious treats. In their study, to be released March 8 in Current Biology, the Duke researchers wanted to see if bonobos would choose to share with an unrelated individual even if they didn't have to.
Bonobos have long intrigued researchers for their unusual (except for us) propensity to cooperate and share with others, a trait not found to the same degree in our close cousin the chimpanzee.
The test subjects had the opportunity to immediately eat the food or to use a "key" to open a door to an adjacent empty room or a room that had another bonobo in it. The test subjects could easily see into the adjacent rooms, so they know which one was empty and which was occupied.
"We found that the test subjects preferred to voluntarily open the recipient's door to allow them to share highly desirable food that they could have easily eaten alone -- with no signs of aggression, frustration, or change in the speed or rate of sharing across trials," explains Dr. Hare. "This stable sharing pattern was particularly striking since in other, nonsharing contexts, bonobos are averse to food loss and adjust to minimize such losses."
abstract van de studie:
uit: Wobber, V., Wrangham, R., & Hare, B. (2010). Bonobos Exhibit Delayed Development of Social Behavior and Cognition Relative to Chimpanzees Current Biology, 20 (3), 226-230
Phenotypic changes between species can occur when evolution shapes development. Here, we tested whether differences in the social behavior and cognition of bonobos and chimpanzees derive from shifts in their ontogeny, looking at behaviors pertaining to feeding competition in particular. We found that as chimpanzees (n = 30) reached adulthood, they became increasingly intolerant of sharing food, whereas adult bonobos (n = 24) maintained high, juvenile levels of food-related tolerance. We also investigated the ontogeny of inhibition during tasks that simulated feeding competition. In two different tests, we found that bonobos (n = 30) exhibited developmental delays relative to chimpanzees (n = 29) in the acquisition of social inhibition, with these differences resulting in less skill among adult bonobos. The results suggest that these social and cognitive differences between two closely related species result from evolutionary changes in brain development.
Dido, een Bonobo-fan...