Spatially constrained locomotion under informational conflict

This study investigates the informational based that supports intentional adaptation of locomotion to spatial environmental constraints. A virtual reality setup was used to present subjects with targets providing normal as well as abnormal optical expansion during locomotor pointing (i.e. positioning of a foot on a visible target on the floor during walking). The manipulation dissociated two variables providing temporal information about time-to-passage (TTP): TTPbeta chi which encompasses target expansion, and TTPchi which is independent of target expansion. While a previous study showed TTPchi to be sufficient, the present results reveal that TTPbeta chi may be used when it is available. This finding indicates that both variables play a role that varies according to the circumstances. Furthermore, the present results provide evidence of the operation of a security principle for action in conflicting situations. (C) 2001 Elsevier Science B.V. All rights reserved.