In this article I survey broadly the literature on cognition, with a children. Among such skills, I shall concentrate almost entirely on language and elementary mathematical skills. This concentration seems to need little justification, since these are the basic skills most important in training handicapped children for productive careers in society. It is als0 the set of skills most important for normal children. This does mean that to some extent I neglect the full range of psychological studies of concept formation in handicapped children. I am excluding the many studies on operant conditioning, reinforcement schedules, paired-associate learning and the like, especially in mentally retarded children. It is possible to make a case that these studies fall within the general area of cognition, but it is also reasonable to exclude them, and I have done so here. There have been a great many studies in the general area I am excluding, and the interested reader will find it easy to get into that literature from some of the survey references given below.I have divided the article into three main parts, treating first problems of language and language development, second, concept formation and abstraction, and third, elementary mathematical skills. As might be expected, the literature on language development, for example, is larger by an order of magnitude than the literature on the development of mathematical skills. I have made some effort to locate studies dealing with mathematical skills, but it will be clear to the reader that additional studies of a substantial nature are needed in order to give a more complete picture of the problems and potentialities of developing mathematical skills in handicapped children.In each of the three parts, I treat first the relatively small literature dealing with cognition in blind children. Second, I survey somewhatsuperficially the enormous literature on mentally retarded children. For
International Reviews of Research in Mental Retardation