Was the experiment with five monkeys, a ladder, a banana and a water spray conducted? (includes illustration waved about in video)
Peace Among the Primates by Robert M. Sapolsky (a slightly longer version entitled
A Natural History of Peace)
Two classic studies have shown that primates are somewhat independent from their “natures.” In the early 1970s, a highly respected primatologist named Hans Kummer was working in a region of Ethiopia containing two species of baboons with markedly different social systems. Savanna baboons live in large troops, with plenty of adult females and males. Hamadryas baboons, in contrast, have a more complex and quite different multilevel society. When confronted with a threatening male, the females of the two species react differently: A hamadryas baboon placates the male by approaching him, whereas a savanna baboon can only run away if she wants to avoid injury.
Kummer conducted a simple experiment, trapping an adult female savanna baboon and releasing her into a hamadryas troop and trapping an adult female hamadryas and releasing her into a savanna troop. The females who were dropped in among a different species initially carried out their species-typical behavior, a major faux pas in the new neighborhood. But gradually, they absorbed the new rules. How long did this learning take? About an hour. In other words, millennia of genetic differences separating the two species, a lifetime of experience with a crucial social rule for each female—and a miniscule amount of time to reverse course completely.
The second experiment was set up by Frans de Waal of Emory University and his student Denise Johanowicz in the early 1990s, working with two macaque monkey species. By any human standards, male rhesus macaques are unappealing animals. Their hierarchies are rigid, those at the top seize a disproportionate share of the spoils, they enforce this inequity with ferocious aggression, and they rarely reconcile after fights. In contrast, male stump tail macaques, which share almost all of their genes with their rhesus macaque cousins, display much less aggression, looser hierarchies, more egalitarianism, and more behaviors that promote group cohesion.
Working with captive primates, de Waal and Johanowicz created a mixed-sex social group of juvenile macaques, combining rhesus and stump tails together. Remarkably, instead of the rhesus macaques bullying the stump tails, over the course of a few months the rhesus males adopted the stump tails’ social style, eventually even matching the stump tails’ high rates of reconciliatory behavior. It so happens, moreover, that stump tails and rhesus macaques use different gestures when reconciling. The rhesus macaques in the study did not start using the stump tails’ reconciliatory gestures, but rather increased the incidence of their own species-typical gestures. In other words, they were not merely imitating the stump tails’ behavior; they were incorporating the concept of frequent reconciliation into their own social practices. Finally, when the newly warm-and-fuzzy rhesus macaques were returned to a larger, all-rhesus group, their new behavioral style persisted.
The Baboon Troop that Mellowed Out After the Alpha Males Died: more on the garbage eating baboons with the alpha males.
