An investigation of bilateral asymmetries in electrodermal activity

Research in cerebral laterality supports the idea that functional differences between the left and right hemispheres exist with respect to cognitive style and perceptual ability. Related research, which has examined autonomic nervous system (ANS) correlates of cerebral laterality, suggests that a component of the ANS, electrodermal activity (EDA), is also lateralized. Some findings in the literature report the occurrence of bilateral asymmetries in phasic and tonic EDA as a function of a left or right hemisphere preference for information processing. This experiment used normal male subjects who were either left or right movers in a test of Conjugate Lateral Eye Movement (CLEM). This selection procedure served to maximize a subject's preference for either a right or left hemisphere mode of information processing. Bilateral EDA was recorded continuously while subjects performed a visual recognition task using word (left hemisphere) and shape (right hemisphere) stimuli. The data do not support the contention that performance on a procedure chosen to selectively activate a given hemisphere elicits asymmetric tonic and/or phasic EDA. The results show no significant difference in the frequency of elicited skin conductance responses under either of the experimental conditions. Bilateral tonic EDA rose continuously over time and did not vary in either hand as a function of task. The present results fail to offer support for either of the hypotheses which argue for 1) increased contralateral excitation with selective hemispheric activation, or 2) increased contralateral inhibition of the EDR with hemispheric arousal.