Performing lateralized approach and avoidance behaviors: effects on perceptual, affective and confidence judgments.

In recent work, we showed that the judgment of affective stimuli is influenced by the degree of congruence between apparently innate hemispheric dispositions (left hemisphere positive and approach, right hemisphere negative and avoidance), and the type of movement produced by the contralateral arm (flexion-approach; extension-avoidance). Incongruent movements (e.g., right arm extension) were associated with attenuation of affective valuations. In the present study, we replicated these results. We also assessed confidence in judgments as a function of stimulus valence and congruence and determined that confidence is maximal with congruent movements and highly positive or negative stimuli, suggesting that congruence effects on affective valuation could be mediated by confidence effects. However, in a second experiment, involving judgments regarding segmented lines, congruence effects were observed only for bisected lines, for which confidence was lowest. Thus, confidence does not provide a unifying explanation for congruence effects in the performance of these two tasks.