The Effects of Repeated Finger Flexion Movements on Self-Reported Affect and Reward System Activation Are Weak and Inconsistent.

Recent research has called into question the robustness and reliability of using body movements to activate motivational systems like approach-reward. The purpose of the current studies was to test the effect of a repeated flexion movement task on approach-reward system activation, positive and negative affect, and persistence on a difficult laboratory task. Results were highly inconsistent across two pre-registered studies-a direct and conceptual replication. In Study 1 (direct replication), undergraduates (n = 216) randomly assigned to the repeated flexion movement condition reported greater positive affect than those assigned to an active control condition. But there were no differences in approach-reward activation or persistence on a difficult laboratory task. In Study 2 (conceptual replication), adult participants (n = 246) randomly assigned to the repeated flexion movement condition reported approach-reward activation than those assigned to an active control condition. But there were no differences in affect or persistence on a laboratory task. Taken together, the effects of repeated flexion movements were inconsistent and weak. The results also highlight how it is possible to cherry-pick positive findings (due to multiple comparisons), culminating in a biased empirical literature.