The Diderot Effect states that obtaining a new possession often creates a spiral of consumption which leads you to acquire more new things. As a result, we end up buying things that our previous selves never needed to feel happy or fulfilled.
The Diderot effect is a social phenomenon related to consumer goods that comprises two ideas. The first posits that goods purchased by consumers will be cohesive to their sense of identity, and as a result, will be complementary to one another. The second states that the introduction of a new possession that is deviant from the consumer’s current complementary goods can result in a process of spiraling consumption. The term was coined by anthropologist and scholar of consumption patterns Grant McCracken in 1988, and is named after the French philosopher Denis Diderot (1713–1784), who first described the effect in an essay.
The term has become common in discussions of sustainable consumption and green consumerism, in regard to the process whereby a purchase or gift creates dissatisfaction with existing possessions and environment, provoking a potentially spiraling pattern of consumption with negative environmental, psychological and social impacts.