Age and Flexible Thinking: An Experimental Demonstration of the Beneficial Effects of Increased Cognitively Stimulating Activity on Fluid Intelligence in Healthy Older Adults

ABSTRACT

The disuse hypothesis of cognitive aging attributes decrements in fluid intelligence in older adults to reduced cognitively stimulating activity. This study experimentally tested the hypothesis that a period of increased mentally stimulating activities thus would enhance older adults' fluid intelligence performance. Participants (N = 44, mean age 67.82) were administered pre- and post-test measures, including the fluid intelligence measure, Cattell's Culture Fair (CCF) test. Experimental participants engaged in diverse, novel, mentally stimulating activities for 10–12 weeks and were compared to a control condition. Results supported the hypothesis; the experimental group showed greater pre- to post-CCF gain than did controls (effect size d = 0.56), with a similar gain on a spatial-perceptual task (WAIS-R Blocks). Even brief periods of increased cognitive stimulation can improve older adults' problem solving and flexible thinking.

keywords:

• Disuse theory of cognitive aging
• Environmental enrichment
• Neuronal plasiticity
• Fluid intelligence
• Successful aging

This research was conducted in partial fulfillment of the requirements for the Ph.D. degree in Psychology at the University of Reading, UK, awarded to Lesley J. Tranter in July, 2006. We would like to thank Dr Judi Ellis for timely and always thoughtful mentoring, Professor Philip Smith for expert statistical advice, and Professor David Warburton for his continued interest and enthusiasm and his astute bibliographical suggestions. Research supported by the Office of Sponsored Research, University of Reading.

Notes

¹ The significance values for the tests of the primary hypotheses are given as one-tailed values. The rationale for this is two-fold: Firstly, if the group exposed to the mentally stimulating activity were to show significantly poorer pre- to post-test levels of performance than that shown by the control group who were not given these activities, this would not be considered to be of particular theoretical interest – since there is no published evidence to suggest this would occur; secondly, it seems reasonable to assume that the experimental effect size, given the relatively time-limited (10–12 week) experimental intervention, is likely to be small, so that this procedure reduces the probability, in this exploratory phase, of a Type II error. As noted in the Discussion, there is a clear need for a larger-scale investigation involving a longer-term manipulation than is used here.