The birth date of modern psychology is usually placed toward the end of 1879 when Wilhelm Wundt designated some space at the University of Leipzig to be used for the conduct of psychological experiments. Of course, the date is arbitrary, as are all such birth dates for disciplines. This arbitrariness arises less from the rival claims of other locations or individuals than from the obvious fact that the birth of a discipline is not a singular event but a complex process extending over a considerable period of time. In the case of psychology the relevant period extends both before and after the magic date.

When psychology became an autonomous field of research it did not invent its concepts and problems out of the blue but took them over from already existing fields like philosophy and physiology. Similarly, the practical activities that came to be identified as methods of psychological re-search were anything but completely new inventions. They were more in the nature of adaptations of already existing practices to a somewhat different context. Those who laid the foundations of a new psychological research tradition were constrained at every step by the traditions of investigative practice with which their general cultural experience or their personal training had made them familiar. The best they could do was to modify these practices, sometimes in quite minor ways, to suit the new goals they had in mind.