RT Journal Article
SR Electronic
T1 Revealing subthreshold motor contributions to perceptual confidence
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 330605
DO 10.1101/330605
A1 Thibault Gajdos
A1 Stephen M. Fleming
A1 Marta Saez Garcia
A1 Gabriel Weindel
A1 Karen Davranche
YR 2018
UL http://biorxiv.org/content/early/2018/05/25/330605.abstract
AB Established models of perceptual metacognition, the ability to evaluate our perceptual judgments, posit that perceptual confidence depends on the strength or quality of feedforward sensory evidence. However, alternative theoretical accounts suggest the entire perception-action cycle, and not only variation in sensory evidence, is monitored when evaluating confidence in one’s percepts. Such models lead to the counterintuitive prediction that perceptual confidence should be directly modulated by features of motor output. To evaluate this proposal here we recorded electromyographic (EMG) activity of motor effectors while subjects performed a near-threshold perceptual discrimination task and reported their confidence in each response. A subset of trials exhibited sub-threshold EMG activity in response effectors before a decision was made. Strikingly, trial-by-trial analysis showed that confidence, but not accuracy, was significantly higher on trials with subthreshold motor activation. These findings support a hypothesis that preparatory motor activity impacts upon confidence over and above performance, consistent with models in which perceptual metacognition integrates information across the perception-action cycle.