Manual Preference in Prosimians, Monkeys and Apes

Bilaterally symmetrical organisms usually respond asymmetrically. Though their structural symmetry is imperfect, their behavioral asymmetry seems disproportionately great. Although most behavioral cues seem to have equal access to both sides of the brain, the two sides of the body do not compete with or duplicate each others’ responses. This occurs despite the obvious mirror-image similarity of the two sides of the brain, each of which is concerned predominantly with the opposite side of the body. This review will focus upon studies of one example of this phenomenon, hand preference in nonhuman primates.