EXTERNAL VALIDITY OF LABORATORY
It is often thought that the use of laboratory experiments in social research involves achieving internal validity at the cost of external validity, or generalization of results to the world outside of the laboratory. Because of this, critics both within and outside the social sciences have argued that the experimental approach that structures so many of our research endeavors is inadequate or inappropriate for the study of social beings. A common criticism of the social experiment concerns its artificiality, or reactivity, and the consequent impossibility of determining the adequacy of generalizations based on experimental data. After reviewing nearly 20 years of research in his field, for example, Cronbach (1975) appeared to have despaired even of the possibility of developing lasting and useful generalizations from social research. A similar theme was sounded by Gergen (1973, 1976), who found social psychology to be more a historical than a scientific enterprise. Our theories, he argued, are little more than post hoc descriptions of the particular set of historical circumstances in which they are developed. As circumstances change, so too must these time bound descriptions.
Gergen coined the term enlightenment effects to identify one central factor that makes it difficult for experimental social research to arrive at stable and lasting generalizations. Owing to the rapid diffusion of information in our society, Gergen argued, social research findings soon become common knowledge. Thus, when people are put in the role of participants, they are likely already to understand the nature of the phenomenon under investigation, and to act in a way that confounds the issue in question. For example, if participants act “as they ought, ” the findings that ensue are not necessarily indicative of people's real, unbiased, out-of-laboratory responses. On the other hand, if they act in ways that are purposely contrary to theoretical expectations, we encounter the same difficulty. There appears no easy, logical solution to the “enlightenment” problem if we grant the unlikely assumption of a highly motivated and well-read public that attends closely to all the latest developments in social science.
While evaluations of the Gergen/Cronbach variety are far from widely accepted (they were strongly opposed by rebuttals from Greenwald, 1976; Godow, 1976; Harris, 1976;