Embodiment and the origin of interval timing: kinematic and electromyographic data
Caspar Addyman1, Sinead Rocha2, Lilian Fautrelle3
1Department of Psychology, Goldsmiths, University of London, New Cross, London, SE14 6NW, UK. c.addyman@gold.ac.uk.
Insights
Infants show early signs of interval timing, the ability to judge short durations, linked to motor control. Surface electromyography (EMG) detected this timing ability even without visible movements in babies as young as 4 months.
Area of Science:
- Developmental psychology
- Neuroscience
- Motor control
Background:
- Interval timing, judging durations from milliseconds to minutes, is linked to action control.
- Understanding the developmental origins of interval timing is crucial for cognitive science.
Purpose of the Study:
- To investigate the emergence of the coupling between interval timing and action control in pre-verbal infants.
- To determine if sub-threshold motor activity reflects interval timing in early development.
Main Methods:
- Utilized surface electromyography (EMG) and motion capture technology.
- Observed 4-, 6-, and 8-month-old infants performing an arm-raising task with varying cycle speeds (4s vs. 2s).
Main Results:
- Time-locked, sub-threshold EMG activity indicative of interval timing was observed in all infant age groups, even without overt motor responses.
- EMG proved more sensitive than behavioral observation for detecting interval timing in infants.
Conclusions:
- The action control system plays a role in interval timing from early infancy.
- Sub-threshold muscle activity measured by EMG is a sensitive indicator of early interval timing development.
Abstract:
Recent evidence suggests that interval timing (the judgment of durations lasting from approximately 500 ms. to a few minutes) is closely coupled to the action control system. We used surface electromyography (EMG) and motion capture technology to explore the emergence of this coupling in 4-, 6-, and 8-month-olds. We engaged infants in an active and socially relevant arm-raising task with seven cycles and response period. In one condition, cycles were slow (every 4 s); in another, they were fast (every 2 s). In the slow condition, we found evidence of time-locked sub-threshold EMG activity even in the absence of any observed overt motor responses at all three ages. This study shows that EMGs can be a more sensitive measure of interval timing in early development than overt behavior.
