Theories of Cognitive Development: Implications for the Mentally Retarded.

Of the six essays in this symposium report, only two address the topic suggested by the title. J. McV. Hunt presents a convincing, well-ordered review of his theory of "psychological development as a hierarchy of learning sets, strategies of information processing, and skills built one upon another in ordinal fashion," and urges that only a much greater understanding of the details of this structure will fulfill its theoretic promise for application to retarded and normal children. R. P. Toister reviews very briefly some implications of behavior technology for mental retardation.

The remainder of the book contains papers only peripherally related to its title: Edward Zigler presents extensive experimental evidence that distorted motivation accounts for part of the poor performance of older retarded children; A. D. Cortazzo urges teachers to pay attention to individual differences; David Elkind describes some differences between lower class and middle class adolescents who produce "borderline