The Effects of Exposure to Pleasant/Unpleasant stimuli on Body Posture:
a Systematic Review and Meta-Analysis
Abstract
Body leaning (indicating directional movements of approach or avoidance)
and sway (indicating reduced mobility or freezing) are often used to
assess respectively approach/avoidance and freezing in response to
emotional stimuli. These responses are typically quantified using force
plates that monitor the displacement of the Center of Pressure. In this
article, meta-analytical analyses were conducted to synthesize findings
from 44 studies (total N participants = 1756) identified from 5
databases, that manipulated the valence of stimuli displayed
—pleasant, neutral, or unpleasant—and measured corresponding body
sway and leaning. The analyses revealed significant heterogeneity in the
reported effects across the studies. Overall, only contrasting pleasant
to unpleasant conditions (vs contrasting pleasant to neutral, or
unpleasant to neutral conditions) resulted in a small meta-analytical
effect size. Moderating variables such as the type of design used and
the duration of exposure to stimuli question the nature of the effects
reported in the literature and indicate a risk of potential confounding
variables. Recommendations for future studies, with an emphasis on
mitigating false negative rate by ensuring a large enough sample size,
are discussed.