Risk aversion in macaques in a freely moving patch-leaving foraging task

Abstract

ABSTRACTAnimals, including humans, are risk-averse in most contexts. A major exception is the rhesus macaque (Macaca mulatta), which is robustly risk-seeking. Macaques‘ unique preferences may reflect their unique evolutionary history. Alternatively, they may derive from elements of task design associated with the demands of physiological recording, the source of nearly all macaque risk preference data. To disambiguate these possibilities we assessed macaques’ risk attitudes in a somewhat more naturalistic environment: subjects foraged at four feeding stations in a large enclosure. Stations (i.e. patches) provided either stochastically or non-stochastically depleting rewards. Subjects’ patch residence times were longer at safe than at risky stations, indicating a preference for safe options. This preference was not attributable to a win-stay-lose-shift heuristic. These findings highlight the lability of risk attitudes in macaques and support the hypothesis that observed differences between macaques and other species are ephemeral, not evolved.