Active control of approach-oriented posture is influenced by emotional reactions

Emotions adaptively prepare the body to interact with the environment through execution of motor actions, but the extent to which emotional states modulate force control during directionally targeted movement tasks remains unknown. We sought to determine how emotions influence active control of approach-oriented posture. Participants (N = 43; 25 females) stood on a force plate and displaced their center of pressure (COP) anteriorly to a target at 50% of their maximum voluntary lean. After 7 s of real-time COP feedback, a picture representing 6 discrete categories (attack, mutilation, contamination, erotic couples, happy faces, and neutral objects) replaced the target and remained on the screen. Participants were instructed to maintain the target COP position throughout the trial. Deviation of the COP position relative to the target (root-mean-square error; RMSE) and error direction (constant error; CE) were evaluated during the feedback and picture portions of the trial. RMSE increased for all affective conditions following feedback occlusion. Following picture onset, lean error exhibited when viewing attack pictures was more anterior (i.e., greater CE) compared with the mutilation, contamination, and erotica conditions. Additionally, participants leaned more anteriorly (i.e., greater CE) during the happy faces condition compared with the mutilation and erotica conditions. Collectively, results indicate that the maintenance of an anterior COP position in the anterior direction is primarily modulated by the motivational direction of emotional stimuli.