For most investigations of expertise, conclusions are drawn about the knowledge representations and strategies of experts through observing their performance of tasks in natural or artificial settings, analyzing verbal protocols that they provide while performing the tasks, and using knowledge-elicitation methods. A major component of research on expertise involves comparing the performance of experts to that of novices on specific tasks in the laboratory. Level of expertise is a subject variable for which the prerequisite training and experience of the experts has occurred prior to task performance. Investigations of experts in a variety of domains with these methods have provided invaluable information about the nature of expert performance and knowledge, and the ways in which they differ from those of novices. However, because the acquisition of the experts' skills is completed prior to the investigation, issues concerning how this expertise was acquired and how it is maintained outside of the laboratory can be investigated only through self-reports. Although self-reports can yield substantial data, they are limited in their ability to provide detailed information about the changes in information processing and performance that occur as the skill develops and the conditions that optimize acquisition and retention of these skills.

Learning and retention have been studied extensively in the laboratory since the earliest days of psychology. For a large part of the 20th century, much of the efforts of experimental psychologists were centered on studying animal learning and human verbal learning (e.g., Leahey, 2003).