title: Head orientation and handedness trajectory in rhesus monkey infants (Macaca mulatta).
abstract: In human and chimpanzee infants, neonatal rightward supine head orientation bias predicts later right hand use preference. In an evolutionarily older primate species such as the rhesus monkey, a left hand preference has been reported, but there are no data on head orientation biases. Supine head orientation bias was measured experimentally in 16 rhesus monkey neonates and compared with prone head orientation bias as well as with various measures of hand use preference. A group-level leftward supine head bias was found that corresponded to greater activity in the left hand while supine; however, supine head orientation did not predict later hand preference as measured by reaching or manipulation on a coordinated bimanual task. These data suggest that a trajectory for handedness in rhesus monkeys may be different from that of humans and chimpanzees.
authors.affiliation: Department of Psychology, University of Massachusetts, Amherst, Massachusetts, USA. eliza_nelson@unc.edu
authors.forename: Eliza L
authors.initials: EL
authors.lastname: Nelson
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Emery
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Babcock
authors.forename: Matthew F S X
authors.initials: MF
authors.lastname: Novak
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Suomi
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Novak
mesh_terms: D000818:Animals; D007839:Functional Laterality / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology; D006257:Head; D008253:Macaca mulatta; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012931:Social Environment