Do primates like babies ? Preference for infantile physical features in nonhuman primates

Abstract : Recent neuroimaging studies empirically showed that baby faces as well as infantile physical images were spontaneously perceived by humans as cute and attractive and elicited strong motivation for caretaking (M. L. Glocker et al. 2008). Endocrine factors influence cuteness perception in humans as perceived cuteness of baby faces varied with hormonal levels (R. Sprengelmeyer et al. 2009). These results are empirical findings supporting the baby schema hypothesis proposed by the ethologist Konrad Lorenz (1943). Whether the baby schema also influences cuteness perception in nonhuman primates remains an open question as literature on preference for infantile physical features is still scarce in animals. Here, we experimentally tested the preference for infantile images by using visual paired comparison (VPC) tasks in two old world monkey species, i.e., Japanese macaques and Campbell’s monkeys. We found that both species preferred to look at infantile images over adult images at the intra- and the inter-specific levels. This is the first empirical demonstration showing the attractiveness of baby infantile physical features in nonhuman primates, raising the question of the evolutionary origins of the instinctive human perception of baby schema.