Beyond Age Comparisons: A Plea for the Use of a Modified Brunswikian Approach to Experimental Designs in the Study of Adult Development and Aging

Abstract

This article makes a plea for experimental designs in the field of adult development and aging using an approach to research inspired by the work of Egon Brunswik. Our recommendations are intended to complement correlational approaches and to enhance the testing of explanatory mechanisms. Our arguments are predicated on the fact that the field of adult development and aging faces particular methodological challenges stemming from the investigation of individual differences approached with age group comparison designs. Many studies on adult development and aging use extreme-group comparisons, contrasting young and older adults, although such comparisons can lead to the overestimation of age-related effects. Moreover, age group membership is used as a proxy variable for psychological processes leading to the observed age-related differences. The inherent correlational design of such age group comparisons can only approximate a test of the underlying psychological processes causing the differences between the groups. We consider these problems and potential solutions to them involving a Brunswikian approach to experimental design in research on adult development and aging, and we discuss implications for theory-predicated research in other subfields of developmental science with similar methodological issues.

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