Reversals in Movement Direction in Locomotor Interception of Uniformly Moving Targets

Gwenaelle Ceyte,Remy Casanova,Reinoud J Bootsma

doi:10.3389/fpsyg.2021.562806

Abstract

Here we studied how participants steer to intercept uniformly moving targets in a virtual driving task. We tested the hypothesis that locomotor interception behavior cannot fully be explained by a strategy of nulling rate of change in pertinent agent-target relations such as the target-heading angle or target’s bearing angle. In line with a previously reported observation and model simulations, we found that, under specific combinations of initial target eccentricity and target motion direction, locomotor paths revealed reversals in movement direction. This phenomenon is not compatible with unique reliance on first-order (i.e., rate-of-change based) information in the case of uniformly moving targets. We also found that, as expected, such reversals in movement direction were not observed consistently over all trials of the same experimental condition: their presence depended on the timing of the first steering action effected by the participant, with only early steering actions leading to reversals in movement direction. These particular characteristics of the direction-reversal phenomenon demonstrated here for a locomotor interception-by-steering task correspond to those reported for lateral manual interception. Together, these findings suggest that control strategies operating in manual and locomotor interception may at least share certain characteristics.

Highlights

More often than not conclusions about the information used in locomotor interception1 are based on the global correspondence of the behavioral patterns observed to one of several heuristically defined interception strategies
Interception performance varied over conditions, with close to maximum performance observed for the Retreat and Cross target directions under the SIDE and CENTER eccentricity conditions
The first goal of the present study was to examine whether reversals in movement direction were to be observed in the locomotor behavior of participants steering to intercept targets moving at constant speed along rectilinear trajectories

Summary

Introduction

More often than not conclusions about the information used in locomotor interception are based on the global correspondence of the behavioral patterns observed to one of several heuristically defined interception strategies (for examples see Kane and Zamani, 2014; Gonzalez-Bellido et al, 2016). Evoked heuristics include continuously moving in the current direction of the target which corresponds to moving so as to maintain target-heading angle β at zero (classical pursuit strategy), continuously moving so as to maintain target-heading angle β constant at a non-zero value (constant target-heading angle or CTHA strategy), and continuously moving so as to maintain the target’s bearing angle θ constant at a non-zero value (constant bearing or CB strategy); see Figure 1 for definitions of pertinent angles. Adopting such a dynamical perspective leads one to focus on transients rather than steady-state regimes

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