The role of motor inhibition in implicit negation processing: two Go/NoGo behavioral studies

Several studies demonstrated that the processing of explicit forms of negation recruits motor inhibitory mechanisms. However, whether this is also true for implicit negation, in which the negative meaning is implicated but not explicitly lexicalized in the sentence (e.g., “I ignore”), has never been studied before. This study aims to address this issue via two Go/NoGo experiments applied to the processing of affirmative, explicit and implicit negation sentences, which differed for the response time-windows to the Go stimulus available to participants. We investigated whether: (i) the processing of implicit negations recruits inhibitory mechanisms; (ii) the inhibitory control mechanisms are differently modulated by implicit and explicit negations. Since we posit that motor inhibitory mechanisms are modulated by both (i) the polarity of the sentence and (ii) the Go/NoGo paradigm, two after-effect analyses on reaction times in Go trials were carried out. Results suggest that implicit negation sentences determine stronger involvement of motor inhibitory mechanisms than the explicit ones. The different processing of the two forms of negation could be explained by the more negative emotional valence of implicit negation and by its inferential nature, which might require deeper processing of the negative meaning, leading to greater activation of the sensory-motor system.