Tópico: Mudanças culturais em grupos de babuínos e outros primatas

[Buckaroo Banzai]

[...] In a study appearing today in the journal PloS Biology (online at www.plosbiology.org), researchers describe the drastic temperamental and tonal shift that occurred in a troop of 62 baboons when its most belligerent members vanished from the scene. The victims were all dominant adult males that had been strong and snarly enough to fight with a neighboring baboon troop over the spoils at a tourist lodge garbage dump, and were exposed there to meat tainted with bovine tuberculosis, which soon killed them. Left behind in the troop, designated the Forest Troop, were the 50 percent of males that had been too subordinate to try dump brawling, as well as all the females and their young. With that change in demographics came a cultural swing toward pacifism, a relaxing of the usually parlous baboon hierarchy, and a willingness to use affection and mutual grooming rather than threats, swipes and bites to foster a patriotic spirit.

Remarkably, the Forest Troop has maintained its genial style over two decades, even though the male survivors of the epidemic have since died or disappeared and been replaced by males from the outside. (As is the case for most primates, baboon females spend their lives in their natal home, while the males leave at puberty to seek their fortunes elsewhere.) The persistence of communal comity suggests that the resident baboons must somehow be instructing the immigrants in the unusual customs of the tribe.

''We don't yet understand the mechanism of transmittal,'' said Dr. Robert M. Sapolsky, a professor of biology and neurology at Stanford, ''but the jerky new guys are obviously learning, 'We don't do things like that around here.' '' Dr. Sapolsky wrote the report with his colleague and wife, Dr. Lisa J. Share.

[...]


http://www.nytimes.com/2004/04/13/science/no-time-for-bullies-baboons-retool-their-culture.html?pagewanted=all&src=pm

[...] In light of these observations, the authors investigated various models that might explain how the Forest Troop preserved this (relatively) peaceful lifestyle, complete with underlying physiological changes. One model suggests that nonhuman primates acquire cultural traits through observation. Young chimps may learn how to crack nuts with stones by watching their elders, for example. In this case, the young baboon transplants might learn that it pays to be nice by watching the interactions of older males in their new troop. Or it could be that proximity to such behavior increases the likelihood that the new males will adopt the behavior. Yet another explanation could be that males in troops with such a high proportion of females become less aggressive because they don't need to fight as much for female attention and are perhaps rewarded for good behavior. But it could be that the females had a more direct impact: new male transfers in the Forest Troop were far better received by resident females than new males in the other troops.

Sapolsky and Share conclude that the method of transmission is likely either one or a combination of these models, though teasing out the mechanisms for such complex behaviors will require future study. But if aggressive behavior in baboons does have a cultural rather than a biological foundation, perhaps there's hope for us as well.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC387823/

Me pergunto se algo próximo do inverso não ocorre de vez em quando com bonobos, talvez principalmente se toparem com chimpanzés.

[Südenbauer]

Os resultados são bem interessantes e é tentador tirar conclusões disso, mas tem que ver direito mesmo o que provocou isso.

Acho que num meio que não necessite de violência, como comentaram, isso pode ocorrer. Exemplo é uma turma de jovens que começam a ser influenciados por um ou dois membros mais briguentos. Quando esses dois elementos saem do grupo, é natural que percam o brio anterior e voltem novamente onde estavam (ao menos que tenha ocorrido uma inserção total do grupo no meio violento). Mas se tu pegar um grupo inerentemente violento, como uma gangue, é natural que sempre vai haver alguém interessado  em tomar a posição de líder.

(sim, eu já extrapolei para os humanos)