Effects of light touch on postural sway and visual search accuracy: A test of functional integration and resource competition hypotheses

- This study is the first using a triple-task context to test functional integration and resources competition hypotheses.
- The results showed the effects of light touch on reducing postural sway during the execution of visual search.
- Also, the results showed greater search accuracy during the application of light touch compared with no touch condition.
- Our findings support functional integration hypothesis that posture can be modulate to achieve the goal of other tasks.

People often multi-task in their daily life. However, the mechanisms for the interaction between simultaneous postural and non-postural tasks have been controversial over the years. The present study investigated the effects of light digital touch on both postural sway and visual search accuracy for the purpose of assessing two hypotheses (functional integration and resource competition), which may explain the interaction between postural sway and the performance of a non-postural task. Participants (n = 42, 20 male and 22 female) were asked to inspect a blank sheet of paper or visually search for target letters in a text block while a fingertip was in light contact with a stable surface (light touch, LT), or with both arms hanging at the sides of the body (no touch, NT). The results showed significant main effects of LT on reducing the magnitude of postural sway as well as enhancing visual search accuracy compared with the NT condition. The findings support the hypothesis of function integration, demonstrating that the modulation of postural sway can be modulated to improve the performance of a visual search task.