ethnicity, race, and culture (e.g., Avolio and Waldman, 1994; Burton and Bengston, 1982; Jackson, 1985). For instance, better cognitive performance in aging individuals is generally associated with higher levels of education (e.g., Birren and Morrison, 1961; Blum and Jarvik, 1974; Denny, 1979; Denny and Palmer, 1981; Green, 1969; Kesler et al., 1976; Ripple and Jaquish, 1981; Schaie and Strother, 1968; Selzer and Denny, 1980), higher-status emploment and higher income levels (e.g., Arbuckle et al., 1986; Schaie, 1983; Gribbon et al., 1980; Owens, 1966), and being white rather than black in the United States (e.g., Fillenbaum et al., 1988). The most precipitous decline in adaptive functioning, which occurs during the eighth decade of life, is far less pronounced in people with greater as opposed to lesser education (Schaie, 1996). The association of education with cognitive functioning in old age varies, however, by country. In Germany, for instance, this association is much weaker than in the United States (Baltes and Mayer, 1999). In addition, there is a growing body of evidence that adult members of sharply different cultures differ systematically in the ways they habitually attend, process, and interpret information as well as in the approaches they take toward the aging process (for a review, see Kitayama, Appendix F).

The true meaning of such associations is not yet understood. However, several interesting hypotheses are available to account for them and to suggest causal mechanisms leading from particular life experiences to their presumed cognitive effects. One set of hypotheses centers on cognitive practice or training. The central idea is that formal education, occupational experience, and the like provide cognitive practice that shapes cognitive abilities and maintains particular ones—perhaps a broad range of abilities for general education and a narrower range for certain occupational experiences. Similarly, cultural differences may provide members of certain cultures with training in ways of thinking that are not practiced in other cultures, resulting in lifelong differences in cognitive skills (Gauvain, 1995). An example from a recent study is the finding that adult native speakers of Italian and English show distinct patterns of brain activation in the temporal regions involved in reading and naming tasks during language processing (Paulesu et al., 2000). This finding is thought to be due to the sharp difference between English and Italian in how closely phonemes (sounds) and graphernes (letter combinations) map onto one another. Importantly, this difference is observed for both words and nonsense words, suggesting that the acquisition of a particular language leads to persistent differences in the processing of new language input.

Another example is the report that formally schooled children are more likely to use the learning strategy called clustering, in which they group like items together explicitly, making recall much easier (Brislin, 1993). This sort of training may help explain differences in memory associated with educational attainment later in the life span. Formal education and experience in wage-labor occupations have been found to be associated with increased con-



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