Perception-Movement Coupling in the Regulation of Step Lengths When Approaching an Obstacle

Abstract

Experiment 1 showed that the control mechanism based on a perception–movement coupling observed in certain goal-directed movement tasks (De Rugy, Montagne, Buekers, & Laurent, 2000; Montagne, Cornus, Glize, Quaine, & Laurent, 2000) can be extended to a stepping across an obstacle task. Regardless of the specificity of tasks, the initiation of regulations is a function of the amount of adjustment. Our participants organized their regulation later than long jumpers. Two additional experiments were conceived to investigate whether this control mechanism could be generalized to goal-directed locomotor displacements, with different constraints. The aim of Experiments 2 and 3 was to address the adaptation of this control mechanism by manipulating the obstacle width and the walking speed in a stepping across task. The results showed that the functioning of this control mechanism could be influenced by the spatiotemporal constraints. Participants' behavior depended on a perception–movement coupling. This study suggests the existence of a generic control mechanism based on a perception–movement coupling, and it emphasizes the adaptation of this type of control mechanism involved in goal-directed displacements.

Notes

¹In a stepping across an obstacle task, obstacle characteristics impose a double boundary: a single boundary-toe (e.g., with the left foot) and a single boundary-heel (e.g., with the right foot).

²This obstacle width was used to oblige participants to achieve accurate foot positioning both before and after the obstacle.

³The standard step length of each participant has been used to manipulate the spatial constraint because the visual adjustment of step length was constrained to appear at a body-scaled value relative to step length (e.g., Berg et al., 1994; Scott, Li, & Davids, 1997).

⁴This obstacle width has been used to oblige participants to perform regulations without an increase in spatial constraint.