Appropriate reactions to erroneous actions are essential to keeping behavior adaptive. Erring, however, is not an all-or-none process: electromyographic (EMG) recordings of the responding muscles have revealed that covert incorrect response activations (termed “partial errors”) occur on a proportion of overtly correct trials. The occurrence of such “partial errors” shows that incorrect response activations could be corrected online, before turning into overt errors. In the present study, we showed that, unlike overt errors, such “partial errors” are poorly consciously detected by participants, who could report only one third of their partial errors. Two parameters of the partial errors were found to predict detection: the surface of the incorrect EMG burst (larger for detected) and the correction time (between the incorrect and correct EMG onsets; longer for detected). These two parameters provided independent information. The correct(ive) responses associated with detected partial errors were larger than the “pure-correct” ones, and this increase was likely a consequence, rather than a cause, of the detection. The respective impacts of the two parameters predicting detection (incorrect surface and correction time), along with the underlying physiological processes subtending partial-error detection, are discussed.

In experimental settings, most overt behavioral errors are consciously perceived. They are, however, only the tip of the iceberg, and electromyographic recording of the muscles involved in the response reveals subthreshold incorrect response activations. Although they are all efficiently corrected, such "partial errors" are poorly consciously detected. Electroencephalographic recordings (CSD estimate), revealed the sequence of cortical activities that lead, or not, to conscious detection. Besides medioprefrontal activities related to action monitoring and error detection, the motor command sent by the primary motor cortices also differed between detected and undetected partial errors: while it develops identically, it is stopped earlier for the latter than for the former, suggesting a critical role in partial error detection. Second, the analysis of the "Error positivity"-Pe, classically linked to error awareness, confirmed its absence just after partial errors, be they detected or not. However, a Pe occurs after the corrective response of partial errors that were detected, suggesting that we become aware of our partial errors only after their correction. The implication of these results for the link between consciousness and cognitive control are discussed.