Using mobile eye tracking to study dogs' understanding of human referential communication.

The extent to which dogs understand human referential communication is among the most studied questions in canine cognition research. While it is widely accepted that dogs follow (some) human referential signals, the way they understand them remains controversial. Here, we applied mobile eye tracking with dogs to investigate during real-world interactions how ostensive pointing and gaze cues direct dogs' visual attention and bias their subsequent choices in an object-choice task. We addressed the question of whether dogs would exhibit a greater response to referential communication compared with other directional cues. Five conditions were tested (pointing, pointing + gazing, gazing, fake throwing and no-cue control), each cue condition indicating the location of a hidden food reward. Results demonstrated that the combination of pointing and gazing significantly increased dogs' attention towards the designated referent. In pointing + gazing, dogs maintained longer attention on the referent compared with other conditions and they approached it significantly above chance levels. While the alternative cue (fake throwing) moved the dogs' gaze to the indicated direction, it did not increase the frequency of gaze shifts to the precise referent location. Our findings highlight that the joint use of pointing and gazing is a particularly effective method for directing dogs' attention to a referent.