Handedness and hemispheric specialization of emotional functions: a comparison of nonhuman primates and humans

Abstract

Research on lateralization can give us information about the way how the hemispheres of the brain are specialized. This is most often studied in terms of handedness, in which either the left or the right hand is preferred. Humans and non-human primates can display a particular hand preference in performing a task depending on the obligate use of a particular hemisphere, with the assumption that manual preferences might be a good index of the functional asymmetries of the cerebral hemispheres. However, it is unknown whether this is possible for the cerebral organization of emotional functioning. Some studies have focused on handedness linked to the organization of emotional functions of the brain. Consistent differences in behavioral style or type may depend on the predominance of the left or right hemisphere in control of processing and behavior. The behavioural studies which link handedness to emotional states have used approach to and manipulation of novel objects and situations as measures of positive emotional states. Based on these findings it is possible to make testable predictions about associations between hand preference and social behavior and emotional states which has been shown to be primarily a function of the regions of the right hemisphere in humans and nonhuman primates. Handedness and the hemispheric specialization of an emotional functions (coping style) seem to be related, i.e. both in humans and nonhuman primates, right-handed individuals appear to be more proactive in their coping style than left-handed individuals. So to humans, nonhuman primates seem to have similar hemispheric specializations and therefore it seems that these hemispheric specializations share a long evolutionary history.