ABSTRACT

The problem of mental subnormality is not new, for history and literature are full of references to individuals who were considered incapable of participating in ordinary life on account of their 'dull wits'. Although around the turn of century educational psychologists, notably Binet, began to make it possible, through the perfection of intelligence testing, to distinguish between various grades of mental subnormality, the concepts employed by the legislators were very confused. The development of mental tests, in particular the Binet-Simon test, had social effects which extended far beyond the sphere of technical diagnosis. Contemporary writing about mental defect is highly critical of the studies of half a century ago that gave such apparent scientific validity to the fear that mental defectives were a parasitic menace to society. The terms 'mental defective' and 'mental deficiency' have been used to describe the mentally subnormal as a whole, irrespective of the extent of their subnormality, but they are tending to fall into disuse.