Does observation of postural imbalance induce a postural reaction?

Area of Science:

• Neuroscience
• Biomechanics
• Motor Control

Background:

• Action observation can elicit contagious responses during social interactions.
• Automatic imitative tendencies are usually inhibited.
• Conditions triggering motor behaviors from mere action observation are unclear.

Purpose of the Study:

• Investigate contagious postural responses during observation of human imbalance.
• Determine if kinematic information alone can trigger motor behaviors.
• Explore the role of gravity constraints and habituation in motor contagion.

Main Methods:

• Participants' body sway was recorded.
• Stimuli included a fixation cross, an upright point-light gymnast, and an inverted display.
• Center of pressure area and antero-posterior path length were measured.

Main Results:

• The upright gymnast display elicited significantly greater body sway compared to control and inverted conditions.
• Kinematic information was sufficient to trigger postural reactions.
• The effect was dependent on the integration of gravity constraints.

Conclusions:

• A contagious postural reaction demonstrates partial inefficiency of inhibitory processes.
• Motor contagion is sensitive to habituation and display orientation.
• Lower-level control mechanisms may facilitate contagion effects.