Previous consumer research studies have shown that consumers do not always retain full control over their decisions. Rather, they make some purchases under partial or even full dependence upon some outside source(s) of influence. Results from these studies, as well as other elements of the consumer research literature, the perceived control literature, and aspects of the gerontological literature were integrated in an attempt to provide a previously missing theoretical explanation for this consumer decision dependency. The perceived control and gerontological literatures provide evidence that certain types of control-related decision dependency behaviors, Primary Control and Harmony Control, of younger and older adult consumers might be different. The purpose of this dissertation was to articulate and test a theoretical model of control-related dependency in decision making. A 3 (age group) x 2 (motivation level) x 2 (ability level) experiment was conducted among young, middle, and older adults. There were 48 subjects per age group. Genders were evenly represented. Expertise and Need for Cognition were covariates. Subjects preferred Primary control to Harmony control. Decision Motivation and self-perceived decision Ability interacted, in that Primary control scores were higher for high-ability subjects making important decisions. There was also an interaction of Motivation and Need for Cognition: Primary control scores were higher for high Need for Cognition, high-Motivation subjects. Older adults scored higher on Primary control than young or middle-aged adults. For Harmony control, high levels of Motivation led to increased Harmony control-related decision behavior. Follow-up analysis revealed a marginally significant interaction in that Low-ability subjects faced with an important decision scored highest on Harmony control. There was an interaction of Age and Motivation on Harmony control. The age groups did not differ in the low-motivation condition; however, in the high-Motivation condition, older adults scored significantly lower in Harmony control than the younger groups. Finally, Age-related differences were found on the four dimensions of Harmony control. Older adults scored lower than their younger peers on the "Rely on Others," "Gai Support and Approval," and "Higher Power" dimensions. They scored higher, however, on the "Wait on Luck" dimension.