This research explored the role that dissociable associative learning and hypothesis-testing processes may play in human sequence learning. Two two-choice SRT tasks were conducted, one under incidental conditions and the other under intentional conditions. In both cases an experimental group was trained on four sub-sequences (i.e. XXX, XYY, YYX and YXY). To control for sequential-effects, sequence learning was assayed by comparing their performance to a control group that had been trained on a pseudo-random ordering, during a test-phase in which both groups experienced effectively the same trial-order. Under incidental conditions participants demonstrated learning of the sub-sequences that ended in an alternation, but not of those that ended in a repetition. In contrast, under intentional conditions XXX showed the greatest evidence of learning. This dissociation is explained using a two-process model of learning, with an associative process (the Augmented SRN) capturing the incidental pattern, and a rule-based process explaining the advantage for XXX under intentional conditions. 3 ACKNOWLEDGEMENTS