Differing Dynamics of Intrapersonal and Interpersonal Coordination: Two-finger and Four-Finger Tapping Experiments

Area of Science:

• Human motor control
• Coordination dynamics
• Psychophysics

Background:

• The Haken-Kelso-Bunz (HKB) model describes inter-limb coordination dynamics.
• Previous studies suggested the HKB model equally describes intrapersonal and interpersonal coordination.
• Finger-tapping tasks are used to study coordination dynamics.

Purpose of the Study:

• To investigate if intrapersonal and interpersonal coordination dynamics are equally described by the HKB model.
• To compare movement stability in different phase modes and finger conditions within and between individuals.

Main Methods:

• Two experiments were conducted: intrapersonal (Experiment 1) and interpersonal (Experiment 2) finger-tapping.
• Participants tapped fingers paced by a metronome, with varying phase modes (in-phase, anti-phase) and finger conditions (two-finger, four-finger).
• Movement stability was assessed in both within-subject experiments.

Main Results:

• Experiment 1 (intrapersonal): No significant difference in movement stability between in-phase and anti-phase modes for the two-finger condition.
• Experiment 2 (interpersonal): No significant difference in movement stability between in-phase and anti-phase modes for the four-finger condition.
• Findings suggest different coordination dynamics for intrapersonal versus interpersonal systems, contradicting HKB model predictions.

Conclusions:

• Intrapersonal and interpersonal coordination systems exhibit distinct dynamics.
• Differences may stem from perceptual information availability and limb interaction complexity.
• The HKB model may not universally apply to both intrapersonal and interpersonal coordination.