Nonexperimental methods have a well-accepted place among the research strategies employed by psychologists. Such methods have long been part of the standard content of textbooks dealing with research methodology (Elmes, Kantowitz, & Roediger, 1985; Festinger & Katz, 1953). In certain areas of the field (e.g., the psychology of personality or abnormal psychology), naturalistic investigations predominate. In other areas (e.g., perception, learning, and memory), the laboratory approach has been preeminent.

Historical perspective

Experimental methods were introduced into psychology during the 19th century, when it was first demonstrated that some psychological questions would yield to a laboratory attack. The success of these first efforts promoted the acceptance of psychology as a science and gave rise to the term “experimental psychology.” Although the meaning of that term has changed somewhat during the last 100 years (Danziger, 1985), the emphasis on the laboratory as a place for empirical explorations has remained and has promoted the scientific status of psychology. Exclusive organizations and journals (e.g., the Society of Experimental Psychologists and the Journal of Experimental Psychology) helped to establish traditions and define a separate, elitist image for laboratory research and for psychologists who used experimental methods. Memory research has been dominated by these traditions for most of the past century. However, demands for ecological validity have challenged these traditions from time to time, and the challenges have been particularly effective during the last decade.