Research Article

A number of important models of information pro- cessing depend on whether processing is serial or parallel. However, many of the studies purporting to settle the case use weak experimental paradigms or results to draw conclusions. A brief history of the issue is given along with examples from the literature. Then a number of promising methods are presented from a variety of sources with some discussion of their poten- tial. A brief discussion of the topic with regard to overall issues of model testing and applications concludes the paper.