Influence of unilateral motor behaviors on the judgment of valenced stimuli

Two experiments were conducted so as to examine how different motor activations (unilateral contraction and extension–flexion paradigms) of the motivational systems of approach and avoidance influenced participants' evaluations of valenced stimuli (figurative expressions and everyday life pictures). The results of the first Study (Study 1) showed that a motor congruence model was operative when processing positive facial expressions, this phenomenon was reversed, however, when negative faces were processed. This occurrence disappeared when weaker negative or positive faces were evaluated. These results were replicated in Study 2 with the use of valenced pictures taken from the International Affective Picture System (IAPS). The overall results were analyzed as a combination of conceptual-motor compatibility and motor congruence models throwing new light on the influence of motor behaviors on judgments.