Abstract
The absence of visual feedback leads to inaccurate representations of one's self-produced force, through an "overcompensation" effect wherein central predictive mechanisms related to reafference result in self-generated forces being perceived as weaker than they are (Therrien et al., 2010; 2012; 2013). These findings hold significant safety implications in situations where repetitive force productions are a requirement of a work environment (e.g., assembly lines). Thus, the goal of this study was to explore this force salience effect in an applied setting to determine if full vision (FV), no vision (NV), or augmented vision (AV) in a motor task involving pinch grips would result in differential force productions. We hypothesized that, consistent with Therrien et al, performing such a task with FV would lead to the lowest pinch grip forces, while NV of the task would lead to compensatory force production. Furthermore, we introduced the concept of AV, through a closed-circuit camera, to determine whether this overcompensation could be mediated by means other than direct visual perception. Twelve participants used a pinch grip to complete a buckle-fastening task in 2 force directions (down and forward) and 3 vision conditions (FV, NV, AV). Impulse measures supported our hypothesis with AV and NV showing a 34.9% and 59.0% increase from FV. Results for the primary variable of interest however, did not (i.e., FV resulted in pinch forces that were not different from NV). Results are discussed in the context of attentional distribution, multi-digit manipulation and task type in the attenuation of self-produced force feedback.
