This research will yield an improved description and understanding of individual differences in the ways in which mature adults describe the controls in their lives, their life styles, their use of substances and the effects this use has on cognitive development. The focus is on a period of development that extends from 40 to 80 years of age. This is a reservoir for effects accumulating from previous periods, and a time in which important features of a person are likely to change. Four cross-sectional studies will be done using exploratory and confirmatory analyses with samples of subjects and variables that are large enough to ensure dependability and generality of findings. New Measures are to be developed; models are to be constructed to establish how beliefs about control relate to patterns of lifestyle that involve attitudes and behaviors pertaining to maintenance of health and physical fitness, use of leisure time, involvement in vocations and avocations, and activities pertaining to use of alcohol, stress control and self control. Analyses to verify control/lifestyle models will indicate how different patterns of use of alcohol operate in combinations with other determiners of adulthood changes in cognitive capabilities. The results will show the extent to which adulthood declines in vulnerable cognitive abilities, principally fluid reasoning and short-term apprehension and retrieval, are associated with, and independent of, the different lifestyles The results will also indicate how enhancements in maintained abilities -crystallized knowledge and retrieval of this knowledge-- are related to lifestyles and beliefs about self improvement. An improved evidence-- based scientific theory about intellectual development will be derived. Scale construction results will provide a basis for further research on lifestyles & beliefs about controls in mature adults. Studies of data- analysis methods, as such, are expected to yield improvements in understanding inference in psychological research and the use of modeling methods with developmental data.