How sequence learning creates explicit knowledge: the role of response-stimulus interval.

Destrebecqz and Cleeremans (Psychon bull rev 8:343-350, 2001; Attention and implicit learning. John Benjamins Publishing Company, Amsterdam, pp 181-213, 2003) reported that increasing the response-stimulus interval (RSI) during incidental sequence learning improved participants' ability to discriminate old and new sequences in a recognition test. However, the original experimental design confounded RSI effects during training and test. I therefore repeated the experiment with an improved design in which RSI was varied systematically during the training phase and the recognition task. Participants learned a sequence of response locations either incidentally or intentionally. As a result, sequence recognition was not affected by the RSI manipulations in the group of incidental learners. With intentional learning instructions, recognition was unaffected by training RSI, but a long RSI in the test phase improved recognition performance over a short RSI. Response latencies while executing the test sequences indicated no effect of training RSI on sequence learning. However, sequence knowledge was expressed more readily when the RSI in the test phase matched the RSI in the training phase.