Assessing sequential knowledge through performance measures: The influenceof short-term sequential effects

Studies on implicit sequence learning have employed the methodology of task dissociations to show that tasks of conscious memory fail to reveal knowle dge expressed in performance measures of learning. One critical requirement of this methodology is that the conscious memory tests tap the same type o f information that is expressed in performance measures. When a determinist ic sequence is being repeated during practice, identification of the exact type of sequential information that is learned can be achieved by a trial-b y-trial comparison between the practised sequence and a control sequence. I n Experiment 1 we examine whether short-term sequential effects are present in choice response time tasks and may therefore contaminate this trial-by- trial comparison. In Experiment 2 we control for these effects and demonstr ate how specification of the exact sub-parts of the sequence that are learn ed is necessary before testing for task dissociations. Our findings indicat e a dissociation between a response time task and a free generation task. T his dissociation, however, is obtained for selected sub-parts of the sequen ce and map be caused by the insensitivity of the free-generation task to lo w confidence knowledge.