Implicit learning of a response-contingent task.

In previous research, relative response speed was revealed to have been used as a predictive cue to guide attention to a target location, in a phenomenon known as "cueing by response." In this study, we explored whether responses can implicitly induce the use of cognitive control, especially in selecting and implementing task-sets. Participants were trained to perform tasks corresponding to different task cues during the training phase. Unbeknownst to participants, the response-contingent group's response to the previous trial determined task type in the subsequent trial, while that of the random group was randomly determined. When the task cue was removed in the testing phase, the percentage of correctly selected response-contingent tasks of the response-contingent group was at a greater level than the chance and the random group, implying that cueing by response can activate appropriate task-sets. The perceptual stimuli did not modulate the task cueing by response, and the response was directly associated with the task. Thus, the results show that top-down control can be carried out even without conscious awareness, using response as a novel type of cue.