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Laterality in spontaneous motor activity of chimpanzees and squirrel monkeys
Author(s) -
Aruguete Mara S.,
Ely Elizabeth A.,
King James E.
Publication year - 1992
Publication title -
american journal of primatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 81
eISSN - 1098-2345
pISSN - 0275-2565
DOI - 10.1002/ajp.1350270303
Subject(s) - preference , squirrel monkey , laterality , primate , scratching , psychology , hand preference , forelimb , population , developmental psychology , neuroscience , medicine , mathematics , statistics , physics , environmental health , acoustics
Varieties of nonmanipulative motor responses were observed in chimpanzees and squirrel monkeys. Chimpanzees displayed a right hand preference for touching their inanimate environments but used their right and left hands equally for touching their faces and their bodies. The latter result was not consistent with previous reports of a left hand preference for face touching in apes. The right hand preference for environmental touching was stronger in male than in female chimpanzees. Squirrel monkeys had a right preference for combined hand and foot responses directed to their bodies, but expressed no handedness for environmentally directed touching. These limb preferences in chimpanzees and squirrel monkeys indicate that neither precise, complex manipulation nor postural instability are necessary conditions for population level hand preferences. Factor analysis of the chimpanzee manual responses showed distinct self and environmentally directed factors. Analysis of the squirrel monkey data also showed self and environmental factors, except that body scratching had a negative loading on the environmental factor. This latter result suggests that self‐scratching by squirrel monkeys is a displacement activity that suppresses manual exploration of the environment. © 1992 Wiley‐Liss, Inc.