Generate and test: an alternative route to knowledge elicitation in an implicit learning task

Three experiments are reported, which examine generation of knowledge in the McGeorge and Burton (1990) invariant learning task. In this task, participants are exposed to 30 four-digit numbers containing an invariant "3". Following this participants then demonstrate a preference for novel numbers containing this invariant over numbers without it. Despite above-chance performance on this pseudo-memory test, participants appear unable to verbalize anything pertinent to the invariant. Here we introduce a novel version of this task, relying on generation of items rather than a preference test. We argue that this new task engages different processing resources, resulting in different patterns of performance. In Experiment 1, invariant learning was demonstrated using a novel fragment completion test. Experiment 2 found that suppressing articulation inhibited learning, implying that this test task accesses phonological knowledge. It is suggested that using the fragment completion test engages different processing resources during test from those in a preference test. Experiment 3 reinforces this position by demonstrating that knowledge appears to transfer across surface features, a result that seems to contradict recent findings by Stadler, Warren, and Lesch (2000). A resolution is offered, drawing on episodic accounts of implicit learning.