This new volume covers studies and reviews published in the period 1975 to 1988. Its focus is not on the evaluation of current research, but rather it calls attention to available works that might be relevant for those wishing to do further research in a specified area. For this reason the editors refer to other reviews of parts of this literature that may provide a somewhat different perspective or that include citations selected on different criteria. When a study deals with more than one major variable or effect, it may be cited in several chapters.