Archived Abstracts
Resilience of experimentally-seeded dietary traditions in wild vervets: evidence from group fissions.
Authors: Erica van de Waal, Carel P. van Schaik, & Andrew Whiten.
The capacity of primates and other animals to sustain behavioral traditions has been rigorously demonstrated through diffusion experiments under controlled laboratory conditions. Such evidence is rarer in the wild, but we show that a behavior experimentally seeded in a majority of individuals within vervet monkey groups may be sustained across several years. Here we report results of two natural fission events in which small splinter groups left a large origin group, that provide novel evidence of the resilience of socially-transmitted group norms of behavior. Before fission, high-ranked females showed strong adherence to a group preference among two food options, originally introduced through a distasteful additive in one option, but no longer present in later tests. Because of monopolization by high-ranked group members, low-ranked females ate more of the formerly distasteful food and so discovered it was now perfectly palatable. Despite this experience, low-ranked females who formed the splinter groups then expressed a striking, 100% bias for the preferred option of their original parent group, a surprising intensity of preference. We interpret this effect as conformity either to the observable preferences of high rankers in the parent group, or to a majority in that group, or both. However, given fissioned individuals’ familiarity with their habitat and the two food types, we question the adequacy of the informational function usually attributed to conformity in animals. We discuss an alternative we call ‘social conformity’: perhaps primates may conform to ‘fit in with the group’ more than to gain information.
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