Public information use by foraging ninespine sticklebacks: social learning or an unlearned social influence on travel direction?

If we are to understand the cognitive basis and evolutionary origins of a particular behaviour, it is necessary to identify its underlying mechanism. Ninespine sticklebacks (Pungitius pungitius) can identify the richer of two prey patches by observing other foragers’ success. This may be due to social learning, or an unlearned social effect on travel direction, brought about by the fish being more likely to face and subsequently travel towards areas where they have observed more feeding activity. Here we show that observer orientation does not predict patch choice, and that fish are still more likely to spend more time in richer patches even if they have to take an indirect route to reach them. This suggests that sticklebacks can learn the location of the richer patch through observation, and viewed in conjunction with other published findings, suggests that learned local enhancement lies behind public information use in this species.