The role of information reduction in skill acquisition

Theories of skill acquisition assume that the effects of practice on task performance are due to either qualitative changes in the task structure, an increased efficiency of performing individual task components, an increased efficiency of performing sequences of task components, or some combination of these mechanisms. We propose an extension to the existing theories by arguing that for many tasks, practice affects which information is processed. More specifically, we argue that people learn, over the course of practice, to separate task-relevant from task-redundant information, and to limit their processing to relevant aspects of the task. In three experiments, subjects verified alphabetic strings, such as M [4] R S T. Strings were correct if they followed the alphabet when the number of letters, given by the digit in parentheses, was skipped. Strings were constructed such that errors occurred only within the initial ''letter-digit-letter'' triplet. Analyses of subjects' RTs for strings of varying lengths demonstrated that: (a) subjects were able to distinguish relevant from redundant task information, and to limit their processing to the relevant information, (b) the ability to reduce the amount of information that is processed takes time and develops gradually over the course of practice, and (c) the mechanism underlying this ability appears to be largely stimulus-independent in the sense that structural components of a task are ignored, rather than specific task information. The findings and their implications for general theories of skill acquisition are discussed. (C) 1996 Academic Press, Inc.