Colloquially this term refers to those changes which occur in later life, but ageing more accurately refers to the changes which occur in any living system over its total lifespan. Where people are concerned, societies divide lifespan in various different ways. For example, one Western social framework sees life as progressing through the stages of infancy, childhood, adolescence and adulthood. The latter may be further divided into early adulthood, middle adulthood and old age. Age may also be defined in terms of biological and psychological markers. These various markers of maturity may be attained at different stages of one’s life. Therefore, knowing someone’s chronological age may only provide a broad indication of their physical and psychological capabilities.
Psychologically, ageing is characterized by a decline in some sensory and cognitive capacities. Research has demonstrated that central cognitive changes may account for a substantial proportion of behavioural differences which occur in old age. One important distinction is that between ‘fluid’ and ‘crystallized’ INTELLIGENCE. Fluid intelligence is broadly synonymous with on-line mental agility. On average, performance on tests which draw heavily on these capacities tend to decline from around one’s early 20s onwards. By contrast, crystallized intelligence is broadly synonymous with knowledge and performance on tasks which load heavily on this capacity tends to increase or remain stable over the lifespan. Some of the age-related decline in fluid intelligence which occurs may occur because older adults have problems spontaneously organizing, structuring or attending to novel information in their environment.
One general hallmark of psychological ageing is that differences in performance between individuals tend to become exaggerated, as the influences of an individual’s specific personal history make their mark. Therefore, it is problematic to attempt to delineate hard-and-fast rules about the capacity of a particular individual at a specific age. A general characteristic of old age is that performance becomes slower on many tasks, whether these are conducted at home or in the laboratory. There is considerable debate in the research literature concerning the extent of this slowing in information processing. However, data indicates that the peripheral (sensory and/or motor) processing speed of older adults is in the region of 1.0–1.5 times slower than that of younger adults whereas central slowing rates indicate retardation in the region of 1.5–2.0 times that of young controls. It has been argued by some (for instance Salthouse, 1985) that all of the deficits in psychological processes which occur in old age may be explained in terms of generic cognitive slowing, though this remains controversial. From a neuropsychological perspective, it has been suggested that older individuals’ pattern of cognitive performance (their relative inflexibility) may be closely related to deficits in frontal lobe functioning which occur as we age.
In terms of MEMORY and LEARNING capacity, older people seem to have problems in actively processing information held in short-term memory, in rehearsing supra-span list lengths and/or in transferring material into long-term storage. In long-term memory, free recall performance is generally more impaired than cued recall recognition in old age, suggesting that old people may have problems in generating and/or using appropriate retrieval cues to access information held in the long-term store. Overlearned and familiar information, well rehearsed motor skills and implicit memory tend to be retained well into old age, although there is often difficulty in learning new facts and acquiring new skills. However, once information has been encoded into long-term memory, it does not seem to be forgotten more rapidly than by younger people. Thus, the general observation that old people spend more time talking about events which occurred in their youth than those which occurred more recently may be at least partly due to problems in encoding new information into long-term memory, rather than in retaining such material. However, as with younger people, learning in older people can be facilitated through active rather than passive learning of to-be-remembered materials.
Personality changes have also been noted anecdotally in old age, with many old people complaining of psychosocial isolation and loneliness. By contrast, observers often comment upon the greater self-centredness which may become apparent in some older people. Antisocial tendencies and personality traits suppressed or inhibited during working life may become more apparent after retirement. However, these proposed changes have proven somewhat elusive when investigated experimentally. It has also been suggested that behaviour in old age becomes dominated by routine and habit. However, there is little evidence that ageing per se is responsible for personality changes which occur across the lifespan. Rather, the literature indicates a basic stability of adult personality traits which are differentially responsive to significant life events and environmental conditions across the lifespan.
References
Craik F. & Salthouse T. (1992) The Handbook of Ageing and Cognition, Lawrence Erlbaum: New Jersey.
Salthouse T.A. (1985) A Theory of Cognitive Ageingy Elsevier: Amsterdam.
JONATHAN K.FOSTER
This is the complete article, containing 788 words
(approx. 3 pages at 300 words per page).
