Walking entrains unique oscillations in performance on a visual detection task

Walking is among our most frequent and natural of voluntary behaviours, yet the consequences of locomotion upon perceptual and cognitive function remain largely unknown. Recent work has highlighted that although walking feels smooth and continuous, critical phases exist within each step-cycle for the successful coordination of perceptual and motor function. Here, we tested whether these phasic demands impact upon visual perception, by assessing performance in a visual detection task during natural unencumbered walking. We finely sampled visual performance over the stride cycle as participants walked along a smooth linear path at a comfortable speed in a wireless virtual reality environment. At the group-level, accuracy, reaction times, and response likelihood showed strong oscillations, modulating at approximately 2 cycles-per-stride (∼2 Hz) with a marked phase of optimal performance aligned with the swing phase of each step. At the participant level, Bayesian inference of population prevalence revealed highly prevalent oscillations that clustered in two idiosyncratic frequency ranges (2 or 4 cycles per stride), with a strong phase alignment across participants.