Anticipatory control of human locomotion requires visuo-spatial attentional resources

The ability to move safely through the world is critical to survival, but a cohesive theory of locomotion has yet to be formed. Here I propose a multilevel theory of locomotor control that describes the guidance of movement using distinct information at each level of control. Fundamental to locomotion is online control, or the guidance of movement using only occurrent perceptual information without high-level cognition. Above this lie the more cognitive Simple Anticipation and Navigation/Learning levels of control that can use top-down information to mediate online control. I present four studies that examine the existence of multiple levels of control and the role that attention plays in modulating these. Experiments 1 and 2 present evidence that supports the theory of levels of locomotor control. Here, people learned to anticipate the movement of obstacles that would collide with them if they failed to anticipate, while they moved under online control when not required to anticipate. Further, there is support in Experiment 2 for both the Simple Anticipation and the Navigation/Learning levels of control, as two distinct phases of anticipatory learning are present. Experiment 3 demonstrates that a simple visuo-spatial distractor impairs the high-level Navigation/Learning level of control, but not the Simple Anticipation level, while a more difficult and complex visuo-spatial distractor in Experiment 4 impairs both higher levels of control and returns control to the online level. I conclude that there is evidence to support the theory of levels of locomotor control, and that the higher two levels of control require visuo-spatial attentional resources.