Although the basic concept of a hedonic treadmill first appeared in an earlier study, a British research psychologist named Michael Eysenck is generally credited with defining and popularizing the "hedonic treadmill" phenomenon. A hedonic treadmill is not a piece of exercise equipment, but rather an analogy for the belief that an increase in material wealth does not necessarily mean an increase in a person's level of happiness. In other words, money does not buy happiness. A person riding the hedonic treadmill may experience a temporary surge or decrease in his or her personal happiness level, but will eventually return to a predetermined and neutral level after adjusting to the circumstances. A lottery winner, for example, may feel more satisfied after paying off debts and purchasing luxury items, but eventually his or her desires and expectations will become relatively average.
Many people find themselves on this theoretical treadmill once they discover how other people live their lives, especially those with more wealth or affluence. A person with an entry-level job could easily adapt to his or her financial circumstances and feel relatively content, for example. This would be the equivalent of running in place on the hedonic treadmill. A financial crisis could set the runner back a few steps, but he or she would most likely return to his or her original level of personal happiness. A sudden increase in wealth or status, however, could temporarily force the runner to work harder to maintain the treadmill's accelerated pace. This is the stage in which people purchase more material goods and upgrade their existing conditions.
The economies of most countries partially depend on this hedonic treadmill phenomenon. Many people have an innate desire to constantly improve their lives, and this often drives them to spend more money on material goods and services. At some point, however, their level of expectation and obligation will become equal to their sense of personal happiness.
From that point on, most consumers will continue to purchase goods and services which help them maintain their current levels of happiness. Once a person trades in a compact car for a luxury sports car, for example, the idea of upgrading to an even more expensive vehicle becomes less and less appealing. The desire to continue upgrading may remain, but the consumer has reached a point of equilibrium on his or her hedonic treadmill.
Running on the hedonic treadmill should not be confused with the selfish excesses of pure hedonism. A poorer person with significant financial debts may feel just as satisfied with his or her life as a wealthy person who has become jaded with consumerism. Studies show that lottery winners and others who have come into sudden wealth only experience a temporary surge in personal happiness levels. Once they have satisfied their essential list of desires and have become financially solvent, many lottery winners report feelings of disappointment that their wealth did not make them feel any different about their lives.
The hedonic treadmill phenomenon does appear to lend credence to the expression "Money can't buy happiness." For most people the pursuit of happiness is just as satisfying as actually finding it.