Sequential aiming in pairs: the multiple levels of joint action

Area of Science:

• Human motor control
• Social cognition
• Cognitive neuroscience

Background:

• Task constraints and movement observation influence individual actions.
• Joint action outcomes are rarely studied in unison.
• Understanding shared action execution is crucial for social interaction.

Purpose of the Study:

• To simultaneously examine underlying processes in joint action.
• To investigate how anticipation and observation affect coordinated movements.
• To differentiate top-down and bottom-up contributions to joint action.

Main Methods:

• Pairs of participants performed sequential aiming movements between two targets.
• Movement contexts included individual (2T1L, 2T2L) and joint (2T2P) conditions.
• Kinematic analysis of movement segments (e.g., velocity, displacement).

Main Results:

• Joint action (2T2P) showed more abrupt first movement segments with lower spatial variability.
• Second movement segments in joint action mirrored the first.
• Leader's movement accommodated the follower; follower's movement was primed by leader's observation.

Conclusions:

• Joint action involves distinct levels of anticipation (top-down) and mapping (bottom-up).
• Co-actors' actions are influenced by both predictive and reactive processes.
• Findings highlight the interplay between individual and social factors in movement coordination.