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Body orientation and face orientation: two factors controlling apes' behavior from humans
Juliane Kaminski1, Josep Call, Michael Tomasello
1Max Planck Institute for Evolutionary Anthropology, Deutscher Plaz 6, 04103 Leipzig, Germany. kaminski@eva.mpg.de
Animal Cognition
|March 23, 2004
Summary
Great apes, including chimpanzees, orangutans, and bonobos, can tell when they are being watched. They use body and face orientation, not just eye gaze, to gauge attention and food disposition.
Area of Science:
- Primate cognition
- Animal behavior
- Social perception
Background:
- Many animal species can detect when observed, but the cues used are unclear.
- Great ape research on gaze detection yields conflicting findings.
Purpose of the Study:
- To investigate how great apes (chimpanzees, orangutans, bonobos) detect human attention.
- To determine if body and face orientation, separately or together, inform apes about being watched.
Main Methods:
- Experiment 1: Apes requested food from a human observer in varied attentional states (staring, eyes closed, back turned, absent).
- Experiment 2: Systematically manipulated observer's body and face orientation (towards/away) to assess ape responses.
Main Results:
- Apes exhibited more behaviors when the human observer was attentive.
- Apes differentiated attentional states based on body and face orientation independently.
- Face orientation signaled perceptual access, while body orientation indicated food disposition.
- Only a few apes responded to the observer's eye state.
Conclusions:
- Great apes use both body and face orientation to infer attentional states and intentions.
- Body and face orientation provide distinct social information to apes.
- Eye gaze is less critical than body and face orientation for apes detecting observation.