Expansive and Contractive Postures and Movement: A Systematic Review and Meta-Analysis of the Effect of Motor Displays on Affective and Behavioral Responses.

This review and meta-analysis explores the experimental effects of expansive and contractive motor displays on affective, hormonal, and behavioral responses. Experimental studies were located through systematic literature searches. Studies had to manipulate motor displays to either expansive or contractive displays and investigate the effect of the displays on affect, hormones, or overt behavior. Meta-analyses were conducted to determine the pooled, standardized mean differences between the effects of motor displays on affective, hormonal, and behavioral responses. From 5,819 unique records, 73 relevant studies were identified. Robust differences between expansive and contractive displays emerged for affective responses and overt behavioral responses across contexts, type of manipulation, and methods of measurement. The results suggest that the effects are driven by the absence of contractive motor displays (contractive vs. neutral displays: Hedges's = 0.45) rather than the presence of expansive displays (expansive vs. neutral displays: = 0.06). The findings stand as a corrective to previous research, as they indicate that it is the absence of contractive displays rather than the presence of expansive displays that alters affective and behavioral responding. Future research should include neutral control groups, use different methods to assess hormonal change, and investigate these effects in the context of ideographic goals.