IMPLICIT LEARNING OF UNIQUE AND AMBIGUOUS SERIAL TRANSITIONS IN THE PRESENCE AND ABSENCE OF A DISTRACTOR TASK

Three experiments investigated the effects of task load, time of secon dary task onset, and response-stimulus time interval on direct and ind irect measures of learning in the M. J. Nissen and P. Bullemer (1987) task. Experiment 1 demonstrated that both unique and ambiguous serial transitions can be learned in the absence and presence of an attention al distractor task. Experiment 2 showed that the time of secondary tas k onset affects the degree to which unique and ambiguous serial transi tions are learned. Experiment 3 demonstrated that the learning of a se quential transition is affected by the length of the time interval bet ween the response to a stimulus and the presentation of the next stimu lus. The findings replicate and extend results reported by A. Cohen, R . I. Ivry, and S. W. Keele (1990) and provide important empirical cons traints for a process model of implicit serial learning.