Do non-human animals copy successful and prestigious models? Disentangling payoff-biased social learning across taxa

As the empirical literature on how social learning across taxa has exploded, some claims that certain social learning strategies [SLSs] are uniquely human have been challenged. While enriching, the interdisciplinary nature of cultural transmission studies has also weakened semantic and conceptual congruence across fields. A theoretical gap has thus been growing between the observed animal behaviors and the hypothesized SLSs underlying them. This review specifically explores the extent to which success- and prestige-biased transmission can be considered uniquely human SLSs. Such ‘copy-if-better-model’ (i.e., indirect bias) strategies are functionally distinct from ‘copy-if-better-variant’ (i.e., direct bias) strategies, though they are both often described as payoff-biased transmission. Perhaps most importantly, ‘copy-if-better model’ heuristics like success- or prestige-biased transmission open up the possibility that maladaptive traits will be transmitted, and have been implicated in the spread of maladaptive behaviors in humans. This paper first proposes broad criteria of cognitive mechanisms that are required for a success- or prestige-biased SLS to be deployed. It then reviews the empirical evidence for these strategies across non-human animals. While several studies call into question the ability of non-human animals to preferentially copy a model in the absence of any immediately and directly observed relative benefits (e.g., payoffs), multiple others meet the criteria for indirectly biased transmission. Observing indirectly biased transmission dynamics across a range of different taxa could be indicative of the adaptive potential of these SLSs. On the other hand, species that rely on this type of SLS are vulnerable to the transmission of maladaptive information, begging the question of how they are able to mitigate the risks inherent in such a low-cost but uncertain heuristic.