title: Lack of evidence that Tonkean macaques understand what others can hear.
abstract: By distinguishing the attentional cues of their mates, animals can learn what part of their environment is of potential interest. However, recognizing the attentional states of others through auditory perception appears to be difficult, since these states are generally not accompanied by ostensive signals liable to reveal them. In this context, one study found that rhesus macaques withhold their action when unobserved, then concluding that they know what others can hear. We replicated this study by testing 18 Tonkean macaques in an experimental setting where subjects had to choose between two boxes containing a food reward. One box made a noise when opened, and the other opened silently. An experimenter was present and could either have her back to subjects or be facing them. If subjects aimed to avoid attracting the experimenter's attention, they were expected to select the silent box while the experimenter's back was turned. Results showed that subjects did not discriminate between boxes, whatever the experimenter's position. We thus found no evidence that Tonkean macaques are able to take the auditory attentional states of a human into account. It is therefore premature to conclude that monkeys can establish a link between hearing and knowing.
authors.affiliation: Département Ecologie, Physiologie et Ethologie, Centre National de la Recherche Scientifique, Strasbourg, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Costes-Thiré
authors.forename: Marine
authors.initials: M
authors.lastname: Levé
authors.forename: Pierre
authors.initials: P
authors.lastname: Uhlrich
authors.forename: Arianna
authors.initials: A
authors.lastname: De Marco
authors.forename: Bernard
authors.initials: B
authors.lastname: Thierry
mesh_terms: D000818:Animals; D001288:Attention; D001307:Auditory Perception; D032882:Comprehension; D003463:Cues; D005260:Female; D008251:Macaca / Q000523:psychology*; D008297:Male; D012919:Social Behavior; D012938:Social Perception