Post-error slowing of balance recovery steps when inhibition is required

The human tendency to slow down immediately following an error is commonly reported in cognitive psychology. This is referred to as post-error slowing (PES), which appears to reflect an engagement of mental resources that impact subsequent behavior.

Is PES evident in a reactive balance task where cancellation of a highly-prepotent balance recovery step is emphasized?

Data were pooled from two studies (N = 41) to investigate PES in a reactive balance context. Participants were released from a supported forward lean, which triggered a rapid balance recovery step. A STOP signal (tone) was occasionally delivered shortly after release of the support cable (i.e., postural perturbation). On these trials, participants were instructed to suppress a step and relax into a secondary, failsafe cable. Force plates detected step responses to measure reaction time post-perturbation (GO cue). The main outcome was step reaction time to determine if reactions slowed immediately following a STOP signal, particularly if a step error occurred.

Participants had significantly slower step reactions following a STOP signal. This was evident both on GO trials after an error and following successful suppression trials. Follow-up analysis revealed that stopping accuracy was inversely correlated with PES. However, this relationship was not present following successful stopping trials.

PES offers a novel way to assess the cognitive contribution to reactive balance, including quantification of how we learn from recent experience and adapt to future events. This may offer an important metric of cognitive control in gait and posture research.