title: Handedness for Unimanual Grasping in 564 Great Apes: The Effect on Grip Morphology and a Comparison with Hand Use for a Bimanual Coordinated Task.
abstract: A number of factors have been proposed to influence within and between species variation in handedness in non-human primates. In the initial study, we assessed the influence of grip morphology on hand use for simple reaching in a sample of 564 great apes including 49 orangutans Pongo pygmaeus, 66 gorillas Gorilla gorilla, 354 chimpanzees Pan troglodytes and 95 bonobos Pan paniscus. Overall, we found a significant right hand bias for reaching. We also found a significant effect of the grip morphology of hand use. Grasping with the thumb and index finger was more prevalent in the right compared to left hand in all four species. There was no significant sex effect on the patterns of handedness. In a subsample of apes, we also compared consistency in hand use for simple reaching with previously published data on a task that measures handedness for bimanual actions. We found that the ratio of subjects with consistent right compared to left hand use was more prevalent in bonobos, chimpanzees and gorillas but not orangutans. However, for all species, the proportion of subjects with inconsistent hand preferences between the tasks was relatively high suggesting some measures may be more sensitive in assessing handedness than others.
authors.affiliation: CNRS, Laboratory of Cognitive Psychology, UMR 7290, Brain and Language Research Institute, Aix-Marseille University , Marseille, France.
authors.forename: Adrien
authors.initials: A
authors.lastname: Meguerditchian
authors.affiliation: Department of Psychology, Trinity University , San Antonio, TX, USA.
authors.forename: Kimberley A
authors.initials: KA
authors.lastname: Phillips
authors.affiliation: CNRS, Laboratoire d'Éthologie Animale et Humaine EthoS, UMR 6552, Université de Rennes 1 , Paimpont, France.
authors.forename: Amandine
authors.initials: A
authors.lastname: Chapelain
authors.affiliation: Department of Psychology, Georgia State University , Atlanta, GA, USA.
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Mahovetz
authors.affiliation: Department of Biology, Kennesaw State University , Kennesaw, GA, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Milne
authors.affiliation: The Dian Fossey Gorilla Fund International , Atlanta, GA, USA.
authors.forename: Tara
authors.initials: T
authors.lastname: Stoinski
authors.affiliation: Smithsonian's National Zoo , Washington, DC, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Bania
authors.affiliation: Department of Psychology, Franklin and Marshall College , Lancaster, PA, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Lonsdorf
authors.affiliation: Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center , Atlanta, GA, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Schaeffer
authors.affiliation: Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center , Atlanta, GA, USA.
authors.forename: Jamie
authors.initials: J
authors.lastname: Russell
authors.affiliation: Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center , Atlanta, GA, USA ; Neuroscience Institute, Georgia State University , Atlanta, GA, USA ; Language Research Center, Georgia State University , Atlanta, GA, USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Hopkins
keywords: grasping; grip morphology; handedness; hemispheric specialization; primate