ABSTRACT
Why experimenting? Why not investigate the recognition performance of the many people who become witnesses to crime everyday “in the field” (i.e., under natural conditions)? The answer is that not all of the things you might want to study occur in the natural environment. Suppose that a researcher is interested in whether or not eyewitness memory is affected by the length of the delay between the crime and the line-up. Will an appropriate range of delays be represented in the cases available for study under natural conditions? Will the researcher have access to all the witnesses? At a time delay similar to their actual participation in the legal process? How can this problem be investigated within experimental eyewitness psychology? What kind of problems have to be solved and which compromises have to be accepted? This chapter discusses the advantages and limits of experimental eyewitness psychology. It aims to give the nonpsychologist an overview of the logic and practice of psychological experiments without discussing the basic logic of science in detail. The scope of this chapter is confined to issues and techniques that are particularly important for research on eyewitness psychology. Experimental designs that are less frequently applied in psychology and law (e.g., time series analysis) are not discussed.
