Using cross correlations to investigate how chimpanzees (Pan troglodytes) use conspecific gaze cues to extract and exploit information in a foraging competition.
In a dyadic informed forager task, chimpanzees (Pan troglodytes) are known to exploit the knowledge of informed subordinates; however, the behavioral mechanisms they employ are unknown. It is tempting to interpret outcome measures, such as which individual obtained the food, in a cognitively richer way than the outcomes may justify. We employed a different approach from prior research, asking how chimpanzees compete by maneuvering around each other, whether they use gaze cues to acquire information from others, and what information they use in moment-to-moment decision-making. We used cross correlations, which plot the correlation between two variables as a function of time, systematically to examine chimpanzee interactions in a series of dyadic informed forager contests. We used cross correlations as a "proof of concept" so as to determine whether the target actions were contingent on, or occurred in a time-locked pattern relative to, the referent actions. A subordinate individual was given privileged knowledge of food location. As expected, an ignorant dominant followed the informed subordinate's movement in the enclosure. The dominant also followed the subordinate's gaze direction: after she looked at the subordinate, she was more likely to gaze toward this same direction within one second. In contrast, the subordinate only occasionally followed the dominant's movement and gaze. The dominant also changed her own direction of movement to converge on the location to which the subordinate directed her gaze and movement. Cross correlation proves an effective technique for charting contingencies in social interactions, an important step in understanding the use of cognition in natural situations.
School of Psychology & Neuroscience, University of St Andrews, St Andrews, United Kingdom; Living Links, Yerkes National Primate Research Center, Emory University, Lawrenceville, Georgia.
Katie
K
Hall
Mike W
MW
Oram
Matthew W
MW
Campbell
Timothy M
TM
Eppley
Richard W
RW
Byrne
Frans B M
FB
De Waal
D000818:Animals; D001288:Attention; D003463:Cues; D005133:Eye Movements; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D002679:Pan troglodytes / Q000523:psychology*; D012919:Social Behavior
cross correlation; gaze following; introduction; social manipulation; tactics of competition