Captive chimpanzees use their right hand to communicate with each other: Implications for the origin of the cerebral substrate for language

摘要

Whether precursors of the left-lateralization for human language can be found in the vocal and gestural communication systems of nonhuman primates remains a topic of intense research, particularly within theoretical discussions of the evolutionary origins of language. Although previous studies in chimpanzees have reported evidence of right-handedness for interspecies food beg gestures produced exclusively toward humans, some might question the generality of these results to intraspecies communicative signals. To address this issue, we recorded hand use in 70 captive chimpanzees for species-typical signals, that could be directed either toward conspecifics or humans. We found evidence of a predominance of right-handedness for species-typical gestures in captive chimpanzees when directed to both humans and conspecifics. Hand preferences during intraspecies communication were significantly positively correlated with gestures directed towards humans. By contrast, hand preferences for gestures did not significantly correlate with hand use for a non-communicative self-directed action. The collective results suggest (a) that evidence of predominance of right-handedness for human-directed gestures communication are not specific to this context and (b) the existence of a specific communicative system involving gestures constitute an ideal prerequisite for the cerebral substrates of human language and its typical left-lateralization.