Stimulus dependence and cross-modal interference in sequence learning.

A central issue in sequence learning is whether learning operates on stimulus-independent abstract elements, or whether surface features are integrated, resulting in stimulus-dependent learning. Using the serial reaction-time (SRT) task, we test whether a previously presented sequence is transferrable from one domain to another. Contrary to previous artificial grammar learning studies, there is mapping between pre- and posttransfer stimuli, but contrary to previous SRT studies mapping is not obvious. In the pre-transfer training phase, participants face a dot-counting task in which the location of the dots follows a predefined sequence. In the test phase, participants face an auditory SRT task in which the spatial organization of the response locations is either the same as spatial sequence in the training phase, or not. Sequence learning is compared to two control conditions: one with a non-sequential random-dot counting in the training phase, and one with no training phase. Results show that sequential training proactively interferes with later sequence learning, regardless of whether the sequence is the same or different in the two phases. Results argue for the existence of a general sequence processor with limited capacity, and that sequence structures and sequenced elements are integrated into a single sequential representation.