ABSTRACT
Most chapters in this book describe probabilistic multidimensional models of perceptual and cognitive tasks. This fact acknowledges several important properties of human information processing. First, performance is not deterministic, but is variable or probabilistic. A subject responds in one way to a stimulus on one trial and responds in another way on another trial. Thus, performance is often characterized by some probability value representing overall response probability to a repeated presentation of a stimulus. Probabilistic performance might result from probabilistic differences in processing, probabilistic differences in the physical stimulus information from trial to trial, or probabilistic representations of prototype items in memory. Second, the term multidimensional refers to the multiple sources of information that influence perception and cognition (Massaro & Cohen, 1991; Massaro & Friedman, 1990).
