The Influence of Advancing Age on Cognition
The Seattle Longitudinal Study The Seattle Longitudinal Study (SLS), introduced in Chapter 2, has been a particularly valu- able source of information regarding adult cognition. In a continuing long-term research proj- ect of about 6,000 men and women that began in 1956, changes in cognitive abilities have been tracked every 7 years over several decades (Schaie, 2013; Schaie et al., 2005). By testing participants on 6 primary abilities originally described by Thurstone (1938), the study was able to show which skills declined, which remained the same, and which grew over time. Data originating from the study quickly began to debunk the conventional notion that aging was best thought of as a downhill slide.
In fact, it may surprise you that the SLS has not found any long-term, consistent pattern of cognitive decline. Individual difference is the rule, and uniform cognitive aging appears not to exist (Schaie & Willis, 2010). There is some evidence of an age-related decline in problem- solving ability beginning in the 30s, but there is no corresponding decline in memory for pieces of fact-based information until many decades later. Importantly, researchers generally found that there is no overall decrease in mental abilities until at least age 60 (see Figure 9.5). On average, it is not until people are their 60s that they even need more time to learn new information (Glisky, 2007).