On the role of asymmetric frontal cortical activity in approach and withdrawal motivation: An updated review of the evidence.

We review conceptual arguments and research on the role of asymmetric frontal cortical activity in emotional and motivational processes. The current article organizes and reviews research on asymmetrical frontal cortical activity by focusing on research that has measured trait (baseline) frontal asymmetry and related it to other individual differences measures related to motivation (e.g., anger, bipolar disorder). The review also covers research that has measured state frontal asymmetry in response to situational manipulations of motivation and emotion and as an intervening variable in motivation-cognition interactions. This review concludes that much research supports the view that greater left than right frontal cortical activity is associated with greater positively or negatively valenced approach motivation. The view that greater right than left frontal cortical activity is associated with withdrawal motivation, although supported, has received less empirical attention. In addition to reviewing research on the emotive functions of asymmetric frontal cortical activity, the reviewed research illustrates the need to consider motivational direction as separate from affective valence in conceptual models of emotional space.