Bottlenose Dolphinsʹ (Tursiops truncatus) Theory of Mind as Demonstrated by Responses to their Trainers’ Attentional States

The present study examined the ability of dolphins to follow the gestural signs presented by human trainers in various attentional states in order to understand the social cognition of dolphins. The human trainers enacted the gestural signs by orienting their bodies and heads in different directions. If the dolphins were attending to the attentional state of the human trainers, their performances would be affected by the orientation of the head only. Results showed, however, that the dolphins’ behaviors were controlled by the orientation of the trainers’ bodies rather than that of their heads. Two additional tests further supported the minimal impact of head orientation on responses to human gestural signs. The present results might be influenced by the current experimental setting, thus we need further efforts to accumulate empirical evidence on social cognition in dolphins.