Dysrationalia: a new specific learning disability.

The concept of selective deficit is the foundation of most conceptual definitions of learning disability. Such definitions have tended to implicate the construct of intelligence in the conceptualization of learning disability and have led to the use of IQ test scores to operationalize the notion of aptitude-achievement discrepancy. The learning disabilities field is only beginning to grapple with the implications of its reliance on the concept of psychometrically defined intelligence. For example, discrepancy-based definitions of learning disabilities guarantee that such disabilities will become more or less prevalent depending on the comprehensiveness of the set of skills assessed on IQ tests. Unlike the vernacular concept of intelligence--which is quite broad--psychometric operationalizations reflect only a thin slice of the mental domain that might be considered cognitive. Thus, it is possible that we have not exhausted the potential set of discrepancy-based disabilities. As a demonstration proof, a new discrepancy-based disability category is proposed and defended in this paper. The disability is one that may force more careful consideration of the role that intelligence plays in conceptual and operational definitions of learning disabilities.