Perceptual and motor contributions to the negative compatibility effect.

The current study focused on contributions to the negative compatibility effect (NCE) from object-updating at the perceptual level and self-inhibition (i.e., automatic motor inhibition) at the response (motor) level. We hypothesized that contributions to the NCE from these two levels were moderated by the strength of stimulus and reaction (S-R) link: object-updating should have greater impact on the NCE with weak S-R links, but both object-updating and self-inhibition should impact on the NCE when the S-R links became strong. To test this hypothesis, in two experiments we used a novel type of stimuli and manipulated mask relevance (relevant versus irrelevant mask) and prime/target compatibility. Participants performed two tasks over three successive days. Results showed that under equivalent masking effectiveness between the two conditions of mask, a significant NCE was observed only in the relevant mask condition when the S-R links were weak, but both close to equal NCE sizes were observed in the two mask conditions when the S-R links were acquired through practice. The results indicated that perceptual and motor contributions to the NCE were moderated by the strength of S-R links, if the strength of the links was too weak to trigger the following inhibition, the NCE primarily originated from object-updating at the perceptual level; if the strength of the links was reinforced by practice, which exceeded the inhibitory threshold, the NCE originated from both object-updating and self-inhibition, but the latter was primarily responsible.