ABSTRACT
The psychological experiment is the basic research tool employed by most of the contributors to this book. With few exceptions, their faith in the experimental method remains firmly secure. Conceptually, the independent variation of different causal factors seems the ideal way to disentangle the natural confounding that otherwise makes arbitrary the choice between alternative explanations. This is the approach that has proven so useful in natural science, and it has also worked in psychology. Perhaps the most enduring examples have been in psychophysics where independent manipulation of simple physical stimuli elicits highly predictable responses, as described by the psychophysical laws of Weber and Fechner. Behavior is predictable when the experimental constraints are arranged with sufficient simplicity and control.
