ABSTRACT
A crucial issue still remains to be discussed. How can we understand intellectual functioning and change in the aged? Much of the confusion in the results of intellectual measurement on normal and abnormal aged individuals and groups will remain until a more satisfactory theory or analysis of the structure of intellect of the aged is available. In this context, ‘structure’ may refer to the components of intellectual functioning suggested by factorial analysis of intelligence measures. Most psychologists who have developed tests of intellectual ability have assumed that the intellectual functioning and its changes with normal ageing are similar in quality or kind and different only in quantity to those resulting from organically based abnormality. However, neurological and psychiatric clinical impressions and the results of psychological investigations as can be seen in the reviews by Yates (1954, 66), Meyer (1960), Willett (1960) and Piercy (1964) suggest that organic lesions in young and old will result in differential impairment of intellectual functioning depending on the size, site and type of cerebral lesion.
