Monkeys form preferences for brand logos repeatedly paired with images of macaque genitals and high status monkeys, even though choosing them provided no tangible rewards (a decision mechanism not operating solely on material outcomes)

Acikalin MY, Watson KK, Fitzsimons GJ, Platt ML (2018) Rhesus macaques form preferences for brand logos through sex and social status based advertising. PLoS ONE 13(2): e0193055. https://doi.org/10.1371/journal.pone.0193055

Abstract: Like humans, monkeys value information about sex and status, inviting the hypothesis that our susceptibility to these factors in advertising arises from shared, ancestral biological mechanisms that prioritize social information. To test this idea, we asked whether rhesus macaques (Macaca mulatta) show choice behavior that is similar to humans in response to sex and social status in advertising. Our results show that monkeys form preferences for brand logos repeatedly paired with images of macaque genitals and high status monkeys. Moreover, monkeys sustain preferences for these brand logos even though choosing them provided no tangible rewards, a finding that cannot be explained by a decision mechanism operating solely on material outcomes. Together, our results endorse the hypothesis that the power of sex and status in advertising emerges from the spontaneous engagement of shared, ancestral neural circuits that prioritize information useful for navigating the social environment. Finally, our results show that simple associative conditioning is sufficient to explain the formation of preferences for brand logos paired with sexual or status-based images.

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Prior studies [15] demonstrated that monkeys will forego fruit juice rewards to view socially-relevant images such as photos of the genitals of males and females and the faces of high status males, suggesting these images have intrinsic value for the animals. An analogous study [24] found that American college students will forego monetary rewards for a glimpse of attractive members of the opposite sex, will wait longer to view attractive individuals than unattractive ones, and will work harder to view more attractive individuals, without being aware they are doing so. These findings suggest that people and monkeys spontaneously, and perhaps subconsciously, value socially-relevant information about others. Endorsing this idea, neurons in reward-related brain areas respond to photos of attractive conspecifics in both people and monkeys [25–27].

Together, these observations invite the hypothesis that receptivity to sex and status in advertising arises from spontaneous activation of neural circuits that prioritize social information in association with neural circuits that process brand information. Associations between a product, a social reward, and the cognitive and physiological state this reward induces in the consumer alone may be sufficient to bias preferences toward the product [28]. Through repeated pairings, brand information, including logos, would eventually become prioritized just as social stimuli are, through the process of conditioning [29]. This simple hypothesis remains to be tested directly in the context of responses to sex and status in advertising. This is an important question, as we do not know whether simple conditioning with socially salient stimuli is sufficient to induce preferences for otherwise neutral logos in the context of sex- and status-based advertising, or whether a more complex, culturally-bound decision process found only in humans is necessary to produce this behavior. In other words, can simple conditioning alone lead to preferences for brands with sexual or social-status based associations? Or, are culturally rooted, complex, and uniquely human mechanisms such as effects of sexual or status-based images on self-concept or selective perception necessary for the formation of such preferences [30, 31]? Because Old World monkeys and humans diverged twenty-five million years ago, the presence of this behavior in both species would suggest evolutionarily ancient origins. Shared brain circuits mediating social perception and valuation in rhesus macaques and humans provide a mechanism by which increased valuation of stimuli associated with social information may be translated into preferences for brands associated with sex and status in advertising [22, 32, 33].