The effect of personal relevance and approach-related action expectation on relative left frontal cortical activity.

Past research using a variety of methods has suggested that the frontal cortex is asymmetrically involved in the experience and expression of positive (or approach motivational) and negative (or withdrawal motivational) affects, with the left frontal region being involved in positive affects (or approach) and the right frontal region being involved in negative affects (or withdrawal). However, some studies have failed to replicate these effects, leaving many scientists questioning the meaning of the past supportive findings. To examine these inconsistencies in results, we tested the hypothesis that increasing the personal relevance of the stimuli and approach motivational intensity would increase relative left frontal activation. Results supported the predictions. Moreover, by showing the predicted effects with anger-inducing stimuli, the results demonstrated that motivational direction, rather than affective valence, accounts for asymmetrical frontal cortical activity.