Half-Decided: Bilateral or Unilateral Stimulation and Susceptibility to Persuasion

The current chapter examines two interrelated questions: (1) Can physical manipulation of the body directly or via sensory input, alter susceptibility toPersuasion persuasion? (2) Can these manipulations be done without the awareness of the persuaded? These issues are considered in the context of known and proposed neurophysiological substrates involved in persuasion, and evidence from several different motor and sensory domains is provided. Specifically, research is reviewed supporting the hypothesis that increased access to right hemispheric processing, either via callosally-mediatedInterhemispheric interactioninterhemispheric interactionHemispheric interaction or via hemispheric activationHemispheric activation, results in increased susceptibility to persuasive messages. A range of body movements and sensory experiences, including unilateral nostril breathingNostril breathing, unilateral gazeUnilateral gaze, unilateral hand clenchingUnilateral hand clenching, bilateral eye movementsBilateral eye movements, unilateral or bilateralAuditory presentation auditory presentation, and body position are examined for their potential to alter hemispheric interactionHemispheric interaction and/or activity and to change performance on tasks across various domains such as memory, creativity, the placebo effectPlacebo effect, and other cognitive processes. Direct examinations of the impact of these manipulations on susceptibility to persuasionPersuasion are few, but of those, auditoryBilateral stimulationstimulationAuditory stimulation in the form of selective frequency amplificationFrequency amplification may be most promising. Practical relevance for consumer behavior and potential clinical applicationsClinical applications in stroke victims are discussed, as are directions for future research. It is concluded that the answers to both questions posed is ‘Yes’ and that future research would be valuable to further delineate the conditions under which these manipulations are effective, as well as for determining the best methods of presentation.