Cognitive Development
Learning Outcomes
- Outline cognitive gains/deficits typically associated with middle adulthood
- Explain changes in fluid and crystallized intelligence during adulthood
Cognition in Middle Adulthood
One of the most influential perspectives on cognition during middle adulthood has been that of the Seattle Longitudinal Study (SLS) of adult cognition, which began in 1956. Schaie & Willis (2010) summarized the general findings from this series of studies as follows: “We have generally shown that reliably replicable average age decrements in psychometric abilities do not occur prior to age 60, but that such reliable decrement can be found for all abilities by 74 years of age.” In short, decreases in cognitive abilities begin in the sixth decade and gain increasing significance from that point on. However, Singh-Maoux et al (2012) argue for small but significant cognitive declines beginning as early as age 45. There is some evidence that adults should be as aggressive in maintaining their cognitive health as they are their physical health during this time as the two are intimately related.
A second source of longitudinal research data on this part of the lifespan has been The Midlife in the United States Studies (MIDUS), which began in 1994. The MIDUS data supports the view that this period of life is something of a trade-off, with some cognitive and physical decreases of varying degrees. The cognitive mechanics of processing speed, often referred to as fluid intelligence, physiological lung capacity, and muscle mass, are in relative decline. However, knowledge, experience and the increased ability to regulate our emotions can compensate for these losses. Continuing cognitive focus and exercise can also reduce the extent and effects of cognitive decline.
Control Beliefs
Central to all of this are personal control beliefs, which have a long history in psychology. Beginning with the work of Julian Rotter (1954), a fundamental distinction is drawn between those who believe that they are the fundamental agent of what happens in their life, and those who believe that they are largely at the mercy of external circumstances. Those who believe that life outcomes are dependent on what they say and do are said to have a strong internal locus of control. Those who believe that they have little control over their life outcomes are said to have an external locus of control.
Empirical research has shown that those with an internal locus of control enjoy better results in psychological tests across the board; behavioral, motivational, and cognitive. It is reported that this belief in control declines with age, but again, there is a great deal of individual variation. This raises another issue: directional causality. Does my belief in my ability to retain my intellectual skills and abilities at this time of life ensure better performance on a cognitive test compared to those who believe in their inexorable decline? Or, does the fact that I enjoy