Do ravens transfer their own past visual access to unseen competitors? (#424)
Complex social interactions are considered one of the main forces driving cognitive evolution. For instance, the ability to understand what another sees, wants, or believes—a “Theory of Mind”—can provide an advantage when competing or cooperating with others. While a number of experiments suggest that some animals possess a basic perception-goal psychology that allows them to understand mental states like seeing, an alternative interpretation states that animals simply associate behavioral outcomes with observable non-mental gaze cues like head and eye orientation. We here describe an experiment on ravens that demonstrates sophisticated social decision-making in the absence of such behavioural cues. We find that ravens trained to use peepholes from one side of a visual barrier respond to the sounds of conspecifics played back from the other side when the peepholes are open but not when they are closed. Specifically, they behave as though they face a visible competitor when the peepholes are open. Our results suggest that ravens mentally simulate the presence of conspecifics and their ability to ‘see’.