People who are high on Openness to experience are generally receptive to entertaining new and challenging facets of cultural life, as well as personal thoughts and emotions (McCrae & Costa, 2003), and studies have reported a positive relationship between Openness to experience and performance on tests of intelligence (Ackerman & Heggestad, 1997; Gignac, Stough, & Loukomitis, 2004). Specifically, in a meta-analysis of studies that examined relationships between personality and intelligence, Ackerman and Heggestad (1997) found Openness correlated positively with both general intelligence (r = .33) and crystallized intelligence (r = .30). Gignac, Stough, and Loukomitis (2004) similarly reported a positive correlation between Openness and general intelligence (r = .43).
One possibility is that Openness has a positive impact on levels of activity engagement, which in turn may facilitate the preservation of intellectual function in old age (Ball et al., 2002). Furthermore, in line with Ackerman’s theory of cognitive aging, which assumes that fluid intelligence (or problem solving ability) cumulatively invested over time transforms into crystallized intelligence (or knowledge) and that the intensity of investment is determined by a person’s Typical Intellectual Engagement (TIE, Goff & Ackerman, 1992; Ackerman, 1994, 1996; Ackerman & Heggestad, 1997), a related possibility is that any effects of Openness and TIE on maintenance of cognitive abilities in older adults is greater for intellectual abilities that belong to the domain of crystallized intelligence (Ackerman, 1994).
We recently examined the relationship between Openness to experience, activity engagement, and cognitive change over time (i.e., across three waves of the Aberdeen Longitudinal Study) using latent growth modeling (LGM). We controlled for the effects of childhood intelligence (age 11 years) and other dimensions of personality in this analysis. Consistent with previous research and theory, we investigated five related hypotheses: (1) that Openness would predict higher scores on tests of cognitive ability (LGM intercept) in older adults; (2) that a positive relationship between Openness and cognitive ability (intercept) in older adults would be mediated in part by activity engagement; (3) that age-related cognitive decline (LGM slope), if present, would be lower in older adults who reported both higher Openness and higher activity engagement and that the positive effect of openness on the rate of cognitive decline would be mediated in part by higher activity engagement; (4) that the positive effects of high activity engagement on cognitive ability (LGM intercept and slope) would be greater for measures of crystallized intelligence (i.e., reading ability) when compared with measures of fluid intelligence (i.e., inductive reasoning, memory, and speed of processing); (5) that the positive effects of Openness and activity on cognitive ability (LGM intercept and slope) would be significant even after controlling for individual differences in childhood intelligence and individual differences in Neuroticism, Agreeableness, Conscientiousness, and Extraversion.
Adults from the local community who were born in 1936 were recruited between 2000 and 2001. All had participated in the Scottish Mental Survey of 1947 when about 95% of children born in 1936 and at school in Scotland on 1st June 1947 were tested using the Moray House Test (Scottish Council for Research in Education, 1949). Participants were assessed across three testing occasions from 2000 to 2005 when aged 64 to 68 years. Data for 406 participants were included in the current analysis (see Whalley et al., 2011, for a detailed description of the sample).
Notably, we found evidence in favor of four of the five hypotheses proposed. Specifically, higher Openness predicted better performance on three of the four tests of cognitive ability included in the study; the positive relationship between Openness and reading ability was mediated in part by activity engagement; the positive effects of high activity engagement on cognitive ability were greater for measures of reading ability when compared with measures of inductive reasoning, memory, and speed of processing; and the positive effects of Openness on ability were significant even after controlling for individual differences in childhood intelligence, Neuroticism, Agreeableness, Conscientiousness, and Extraversion.
Ackerman’s theory of cognitive aging assumes that fluid intelligence cumulatively invested over time transforms into crystallized intelligence (or knowledge) and that the intensity of investment is determined by Typical Intellectual Engagement (TIE, Ackerman, 1994, 1996; Ackerman & Heggestad, 1997). At the same time, our results suggest that this intensity of investment may be a function of higher Openness and higher Conscientiousness, as both Openness and Conscientiousness predicted higher activity levels. Nevertheless, the positive effects of Openness on performance over-and-above both childhood intelligence and activity levels in the current study suggests that there may be some unique effects of Openness on cognitive ability in late adulthood.
Notably, the construct of Openness to experience measures the tendency to fantasize, an aesthetic sensitivity, awareness of one’s emotions, preference for novelty, intellectual curiosity, and preference for nontraditional values (McCrae & Costa, 2003). As such, Openness is broader in scope than TIE (Ackerman, 1996), which measures individuals intellectual curiosity and preference to engage in cognitively demanding or challenging leisure tasks and activities, such as reading, problem solving, and abstract thinking. The artistic imagination, aesthetic, independent and nonconforming aspects of Openness (Deraad, Hendriks, & Hofstee, 1992; Johnson, 1994) may be critical drivers of broader patterns of cognitive activity and experience that help to sustain higher levels of cognitive complexity throughout adulthood. This is consistent with research by Parisi and colleagues (2009) who have reported a positive relationship between self-reported measures of alertness to novelty and intellectual complexity and performance on tests of fluid intelligence.
The implications of our results are as follows. Overall, both Openness and activity engagement appear related to preserved higher cognitive ability in older adults, with Openness having a direct effect on marker tests of fluid ability and with the combined influence of both Openness and activity being particularly important for marker tests of crystallized intelligence. Given that we did not observe significant cognitive decline in our sample, further research and follow-up on the Aberdeen cohort is needed to clarify if higher Openness and higher levels of activity engagement predict slower rates of cognitive decline. Further empirical and theoretical work is also needed to better understand the mechanisms through which openness positively influences cognitive ability. To the extent that openness is amenable to experimental manipulation, researchers can begin to investigate specific mechanisms through which openness influences cognitive ability. This research may also have implications for the future development of cognitive training programmes for older adults. For example, the preference for novelty which is a defining feature of openness may be akin to what Ellen Langer has described as mindfulness, or “noticing novelty, drawing novel distinctions”, a process that is both amenable to experimental manipulation and positively related to cognitive performance in some situations (Chanowitz & Langer, 1981). Experimental insights can be used to inform future longitudinal research that examines, for example, the neuroscientific basis of the link between openness to experience and cognitive ability across the lifespan. This work will help researchers to derive a more comprehensive theory explaining the link between openness and both fluid and crystallized intelligence.
For a full list of references cited, see Hogan, M.J., Staff, R.T., Bunting, B.P., Deary, I. J., Whalley, L.J. (2012). Openness to experience and activity engagement facilitate the maintenance of verbal ability in older adults. Psychology and Aging.