Foraging nine-spined sticklebacks prefer to rely on public information over simpler social cues

Social animals can observe others' behavior and in the process acquire information of varying quality about a given resource. Theoretical models predict that blind copying of others' behavior is more likely when individuals are only able to observe the decisions (here "social cues") of others rather than the cues (here "public information") on which such decisions are based. We investigated information use by nine-spined sticklebacks (Pungitius pungitius) in a two-patch foraging context. Social cues were provided by the number of demonstrator fish present at each patch (two versus six), which either conflicted with the demonstrators' observed feeding rate at each patch (public information) or was the only information available. Consistent with predictions, observers preferred the patch previously associated with six demonstrators when social cues were the only available source of information but preferred the patch previously associated with two demonstrators ("rich" patch) when also provided with public information. On the bases of these experiments, we argue that it is because these fish preferentially base decisions on public information rather than social cues that they can potentially avoid engaging in erroneous informational cascades. Thus, the availability of public information can help social animals make adaptive decisions.