Do Primates have culture?

I would suggest in your troop of chimpanzees, that if those who signed were the ones with dominant status, eventually all or nearly all of the troop members would sign. Were they not dominant, i would suggest that teaching sign language would only take place between the signing chimpanzees and their offspring. Perhaps, the signing chimpanzees would eventually succeed to dominant status, and all of the troop might eventually sign to one another.

There are also some interesting implications in this about the origin of "conservative" and "liberal" attitudes among humans.

Once Rowdy Baboon Troop Now Follows Path of Peace

By Sue Goetinck Ambrose
... In 2004, the flower-power award may go to a troop of (Olive) baboons.

Researchers have found that a group of baboons living in Kenya has gone from nasty to sweet.
"... the first time anyone has seen anything resembling manners passed between generations in wild animals.

...findings are part of a growing body of evidence contradicting older notions that violence and aggression in humans and their primate cousins are inevitable.

"It would be great if people come out of here thinking there's more flexibility, there's more capacity to make the world a better place," said Robert Sapolsky, who led the study. "If ... (baboons) can do it, maybe we can, too."

Sapolsky, a neuroscientist at Stanford University, and colleague Lisa Share documented the peace movement in a troop of olive baboons that lives in Kenya's Masai Mara Game Reserve....

Reports exist of transmission of culture in nonhuman primates. We examine this in a troop of savanna baboons studied since 1978. During the mid-1980s, half of the males died from tuberculosis; because of circumstances of the outbreak, it was more aggressive males who died, leaving a cohort of atypically unaggressive survivors. A decade later, these behavioral patterns persisted. Males leave their natal troops at adolescence; by the mid-1990s, no males remained who had resided in the troop a decade before. Thus, critically, the troop's unique culture was being adopted by new males joining the troop. We describe (a) features of this culture in the behavior of males, including high rates of grooming and affiliation with females and a "relaxed" dominance hierarchy; (b) physiological measures suggesting less stress among low-ranking males; (c) models explaining transmission of this culture; and (d) data testing these models, centered around treatment of transfer males by resident females.

(Received November 14, 2003; Accepted February 18, 2004; Published April 13, 2004)

A converse issue concerns circumstances that might destroy the F93-96 culture. The culture might be destroyed if numerous males transfer into the troop simultaneously, or if a male transfers in who, rather than assuming the F93-96 culture, instead takes advantage of it. Game theory suggests that F93-96 would be vulnerable to such "cheating."

Another issue concerns the fate of natal males from F93-96 when they transfer elsewhere. Reciprocal altruism models (Axelrod and Hamilton, 1981) suggest that if one F93-96 male transfers elsewhere and continues his natal behavioral style, he will be at a competitive disadvantage. However, should two F93-96 males simultaneously join another troop and maintain F93-96-typical interactions between them, they might be at a competitive advantage. This might represent a means to transmit this social style between troops.