Timing of responses to gradual and abrupt visuo-proprioceptive cue conflict with and without feedback

When people observe conflicting visual and proprioceptive cues about their static hand position, visuo-proprioceptive recalibration results: the proprioceptive estimate of hand position shifts toward the visual estimate, and vice versa. Recalibration also occurs during gradual or abrupt visuomotor adaptation, in response to both cue conflict and sensory prediction errors experienced as the hand reaches to a target. Here, we asked whether creating a cue conflict gradually versus abruptly, or providing error feedback, affects recalibration in a static hand. We examined participants' responses to a 70 mm conflict imposed by shifting the visual cue forward from the proprioceptive cue (static left hand). Participants pointed with their unseen right hand to indicate perceived bimodal and unimodal cue positions. Conflict was introduced gradually (groups 1 and 2) or abruptly (groups 3 and 4), with performance feedback present (groups 2 and 4) or absent (groups 1 and 3). For abrupt groups, most behavioral change occurred immediately after the conflict began. No-feedback groups (1 and 3) showed comparable magnitudes of overall recalibration, indicating that abrupt and gradual conflicts result in similar recalibration but with different timings. Proprioceptive recalibration occurred in the presence of error feedback (groups 2 and 4); however, recalibration was not increased by the addition of error-based processes. Control groups confirmed accurate performance on the pointing task despite the visual cue shift. These findings highlight the distinct timing of recalibration mechanisms for gradual versus abrupt cue conflicts and potential smaller contribution of error mechanisms for a cue conflict in a stationary hand.NEW & NOTEWORTHY The brain may handle spatial conflicts between visual and proprioceptive cues differently for a dynamic hand undergoing visuomotor adaptation than for a static hand. In a static hand, abrupt conflict triggered immediate recalibration without further adjustment, and feedback had little impact on recalibration. This suggests varying roles of multisensory and error mechanisms across motor contexts, underscoring the importance of examining a variety of motor contexts to understand and predict behavior.