title: The distribution and development of handedness for manual gestures in captive chimpanzees (Pan troglodytes).
abstract: This article describes the distribution and development of handedness for manual gestures in captive chimpanzees. Data on handedness for unimanual gestures were collected in a sample of 227 captive chimpanzees. Handedness for these gestures was compared with handedness for three other measures of hand use: tool use, reaching, and coordinated bimanual actions. Chimpanzees were significantly more right-handed for gestures than for all other measures of hand use. Hand use for simple reaching at 3 to 4 years of age predicted hand use for gestures 10 years later. Use of the right hand for gestures was significantly higher when gestures were accompanied by a vocalization than when they were not. The collective results suggest that left-hemisphere specialization for language may have evolved initially from asymmetries in manual gestures in the common ancestor of chimpanzees and humans, rather than from hand use associated with other, non-communicative motor actions, including tool use and coordinated bimanual actions, as has been previously suggested in the literature.
authors.affiliation: Division of Psychobiology, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30322, USA. lrcbh@rmy.emory.edu
authors.forename: William D
authors.initials: WD
authors.lastname: Hopkins
authors.forename: Jamie
authors.initials: J
authors.lastname: Russell
authors.forename: Hani
authors.initials: H
authors.lastname: Freeman
authors.forename: Nicole
authors.initials: N
authors.lastname: Buehler
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Reynolds
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Schapiro
mesh_terms: D000367:Age Factors; D000818:Animals; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D005868:Gestures; D008297:Male; D002679:Pan troglodytes; D011597:Psychomotor Performance / Q000502:physiology; D034941:Upper Extremity / Q000502:physiology*; D014828:Vocalization, Animal