What Is the Hedonic Treadmill? Returning to the Same Level After Everything

The idea holds that satisfaction is largely determined by a stable individual set point, that events move a person above or below it temporarily, and that adaptation returns them to roughly where they were. The evidence offered included studies finding that people who had won large sums reported satisfaction not much higher than comparison groups some time afterwards, and that people who had suffered serious injury reported levels considerably higher than expected. The implication drawn was pessimistic about improving circumstances, since any gain would be adapted away, and it was widely popularised in that form. The underlying mechanism is general and well supported, since adaptation to a constant stimulus is a basic property of perception and applies to temperature, brightness, smell and sound, and extending it to circumstances is a reasonable move.

Later work with better data revised several parts of the picture:

• •Long-running studies following the same people for decades found that a substantial minority show lasting changes in satisfaction rather than returning to a set point
• •Adaptation is incomplete for several major events, with unemployment, disability and bereavement all showing lasting reductions on average
• •Adaptation to positive events is generally faster and more complete than to negative ones, which is an asymmetry the original account did not predict
• •The famous lottery and injury findings rested on small samples and have not been cleanly replicated
• •Income has a real relationship with reported satisfaction, weaker than people expect and not zero, and the shape of it is contested
• •Variation between individuals in how much they adapt is large, which a single set point does not accommodate

The useful version of the idea distinguishes between the things people adapt to easily and the things they do not. Adaptation is fast and near complete for conditions that become constant and unremarkable, which covers most material improvements, since a better home, a faster commute or a higher salary quickly become the background rather than a source of pleasure. Adaptation is slow or absent for conditions that continue to intrude, which includes chronic pain, noise, a poor relationship, a long commute that remains stressful each day and persistent insecurity. That distinction has a practical implication that the pessimistic reading obscures, since it suggests that removing recurring irritations produces more lasting benefit than acquiring things, and that changes affecting the texture of ordinary days matter more than changes affecting status or possessions.

Everything in this area rests on asking people how satisfied they are, and the properties of that measurement deserve attention. A single question asking for a rating on a numbered scale is the standard instrument, and it is sensitive to influences that have nothing to do with the underlying state, including the weather at the time of asking, whether a preceding question raised an unrelated topic, and the order in which options are presented. Experience sampling, which asks people how they feel at random moments, produces different answers from retrospective questions, since remembered experience weighs peaks and endings rather than duration. Comparing across cultures is harder still, since scale use differs systematically and the words translate imperfectly. Researchers address these with multiple instruments and large samples, and the field remains one where the measurement is a substantial part of the subject rather than a preliminary to it.

The conclusions with reasonable support are narrower than either the original claim or the popular advice built on it. Circumstances explain less of the variation between people than most people assume, with personality and temperament accounting for a substantial share. Social relationships show up consistently as more strongly associated with reported satisfaction than material factors. Comparison matters, since satisfaction depends on relative position rather than absolute level for many goods, which explains why rising general prosperity produces smaller gains than individual advancement. Activities with ongoing engagement adapt less than acquisitions. And measurement itself is contested, since asking people to rate their satisfaction produces answers sensitive to mood, to question order and to what happened recently, which means the whole field rests on a foundation that is softer than the precision of its numbers suggests.

People adapt towards a familiar level, and the strong version claiming a fixed set point failed against long-running studies showing lasting change for a substantial minority. Adaptation to good events is faster and more complete than to bad ones. Constant unremarkable improvements are adapted away, while recurring intrusions are not, which means removing daily irritations outlasts acquiring things.