The writer is indebted to the following colleagues for helpful suggestions and comments on an earlier version of this paper: Roger Barker, L. B. Kornreich, Eugene Levitt, and Lawrence Linn. Thanks are also due to Anthony Fazio and James Green who supplied unpublished studies for review, and to Dean Bolton and Douglas Simpson for library work. Locating relevant references was facilitated by Deutscher's bibliography (1966a). This research was supported by a grant from the Graduate School of the University of Wisconsin-Milwaukee and National Institute of Mental Health Grant 1 R03 MH-15798-01. Portions of this paper were presented at the Western Psychological Association Convention, Vancouver, B.C., June 20, 1969.