This dissertation deals with the motivational foundations of consumer behavior. The dissertation utilizes insights mainly from motivational psychology, biology, and neuroscience to investigate why we are motivated to consume certain goods, but not others. In particular, the dissertation emphasizes that parts of our motivation can be understood in terms of needs and their deprivation. The dissertation contains three main chapters (4, 5, and 6). Chapters 4 and 5 deal with intertemporal choice and impulsive consumption. Chapter 4 presents a new intertemporal choice model and shows that impulsive choices can be understood by utilizing recent neuroscientific findings suggesting that cue-triggered “wanting” can be a reason for the occurrence of impulsive urges. When driven by cue-triggered “wanting”, individuals sometimes impulsively “want” rewards, although they do not necessarily “like” the rewards. Chapter 5 uses the cue-triggered “wanting” mechanism to explain that individuals oftentimes buy identity-relevant goods such as clothes in an impulsive fashion. The chapter argues that the “wanting”-“liking” dissociation can explain the regret that individuals sometimes perceive after having bought identity-related products on impulse. Based on the knowledge of the cue-triggered “wanting” mechanism, especially in context of identity-related consumption, the chapter presents implications for libertarian paternalistic policy advice. More precisely, the chapter illustrates how nudges can be used to either reduce unnecessary impulsive consumption or increase the frequency with which ethical goods are impulsively consumed. Finally, chapter 6 presents a formal model explaining the changes in consumer behavior over the long run based on needs and their deprivation patterns. The model explains, for example, the empirical regularity that expenditure shares devoted to food consumption decrease with rising income.