Fueled by increased life expectancy and an unprecedented cultural obsession with youthfulness, contemporary society is witnessing a growing fascination among individuals with their ageing process. Rather than passively accepting their age, consumers are actively engaged in monitoring and managing their ageing journey. This active involvement is evident in the rapid expansion of the anti-ageing and longevity industries, which cater to the desire for youthful vitality. Various forms of popular media, such as best-selling books, podcasts, and streaming videos related to ageing, are also reflecting the trend. Consequently, how individuals perceive their subjective ageing experience is becoming increasingly significant, often overshadowing objective age.

Prior research in developmental psychology and gerontology has revealed that subjective age—referring to how old an individual feels—can predict important developmental and psychological outcomes. However, limited studies have explored how subjective age influences consumer behaviour and decision-making processes, highlighting the need for further research to address critical research gaps. Thus, this thesis aims to paint a more comprehensive picture of how subjective age shapes consumer behaviour. The first essay, titled “Is Technology the New Fountain of Youth?: Feeling Older Increases the Consumption of New Technologies,” investigates how a temporary increase in subjective age influences the consumption of new technologies. Drawing upon previous research on compensatory consumption, the research proposes that consumers will strategically gravitate toward new technologies when they feel older in an attempt to regain a sense of youthfulness. Three controlled experiments provide converging evidence supporting this prediction.

The second essay, “Feeling Younger and Acting Greener: The Impact of Subjective Age on Sustainable Consumption,” examines how momentary shifts in subjective age influence sustainable consumption. Building upon previous research on consumer identity, the research suggests that consumers prefer sustainable products when they feel younger, as these products align well with their activated youthful age identity. The results from three lab experiments support this proposition.

Combined, the findings of the thesis address research gaps within the literature and offer theoretical and practical implications. Theoretically, the thesis contributes to the growing literature on the malleability of subjective age by extending its impact on two crucial consumer domains: new technology adoption and sustainable consumption. It also uncovers two unique underlying mechanisms—perceived youthfulness provision and perceived fit. Additionally, the thesis offers unique insights into existing research by providing evidence for both a contrast and an assimilation effect of subjective age and demonstrating that momentary increases or decreases in subjective age affect consumers of all age-groups rather than just older adults. From a practical standpoint, the findings of the thesis equip marketing practitioners and policymakers with tools to promote the consumption of new technologies and sustainable products by actively crafting marketing strategies that induce feelings of being older or younger.