Warr (1992, 2001) and Kanfer and Ackermann (2004) reviewed literature on cognitive abilities and age, and found that cognitive abilities change with age: crystallized intellectual abilities, such as general knowledge and verbal comprehension, increase, and ﬂuid intelligence, such as working memory, abstract reasoning, and speed of reaction, decrease.
Kanfer and Ackerman (2004) propose that these changes affect motivation by changing the amount of effort required to sustain performance. However, this compensatory motivational strategy will be undermined by the negative effects on the psychological factors (e.g. self-efﬁcacy) that normally support motivation. Furthermore, in tasks with high demands on ﬂuid intelligence, motivation among older workers may be diminished as the discrepancy between comfortable effort level and the demands of the task increases (we will return to this point in the next paragraph). In tasks demanding both ﬂuid and crystallized intelligence, the potential drop in work motivation can be attenuated by changing the working role to reduce the demands on ﬂuid intelligence. Overall, previous studies are inconclusive regarding the associations between psychological age and motivation; cognitive abilities can have either a positive or a negative impact on motivation to continue to work.