Motor and cognitive integration: effect of bilateral behaviors on judgment.

Performing approach vs. avoidance behaviors (arm flexion vs. arm extension) on the one hand, and lateralized peripheral activations (left side vs. right side) of the motivational systems of approach vs. avoidance, on the other hand, have been shown to impact on cognitive functioning (Cretenet, & Dru, 2009), mainly in judgment tasks. When a unilateral motor congruent behavior; that is, a behavior that activates the same motivational system (e.g., flexion of the right arm) was performed during a judgment task, participants' use of complex, interactive information integration rules was facilitated. No effect was, however, found when simpler, additive rules were involved (Mullet, Cretenet, & Dru, 2014). Three experiments are reported here that examined the effect of bilateral motor behaviors (e.g., flexion of the right arm and extension of the left arm) on the implementation of information integration rules. In Studies 1 and 2, two judgment tasks similar to the ones used by Mullet et al. (2014) were used: (a) a complex task in which participants judged a person's attractiveness from personality information, and (b) a simpler task in which they attributed blame according to bad deeds. It was found that similar motor behaviors performed by the two arms (e.g., flexion of both arms), in contrast to dissimilar ones, facilitated the use of complex, interactive information integration rules. No effect was found in the case of simpler integration rules. In Study 3, these results were replicated in a judgment task in which the complexity of the integration rule varied depending on the instructions given. Overall, when bilateral motor behaviors were performed during judgment, facilitation in the use of complex integration rules no longer depended on motivational congruence as in the case of unilateral motor behavior. It depended on symmetry/similarity of behaviors.