What is the impact of the explicit knowledge of sequence regularities on both deterministic and probabilistic serial reaction time task performance?

The aim of this study was to explore the role of prior explicit sequence knowledge by comparing its influence on serial reaction time (SRT) performance with either a deterministic or a probabilistic sequence. The results confirm that, with a deterministic sequence, preliminary explicit learning improves SRT performance. On the other hand, with a probabilistic sequence, the results show no advantage for SRT performance in explicit-learning conditions. In addition, by using the process dissociation procedure (Jacoby, 1991), we show that performance on a subsequent generation task was more sustained by controlled processes for participants in the explicit-learning conditions than for those in the incidental condition. On the whole, these results, showing that the influence of explicit knowledge can be suppressed in certain specific conditions, are consistent with the intervention of both implicit and explicit mechanisms in SRT tasks, and the results also show that their relative influence can be modulated by the particular demands of the task.