Hedonic treadmill
The hedonic treadmill, also known as hedonic adaptation, is the conjecture that humans quickly return to a relatively stable level of happiness despite major positive or negative events or life changes. According to this theory, as a person makes more money, expectations and desires rise in tandem, which results in no permanent gain in happiness.
Overview
Hedonic adaptation is an event or mechanism that reduces the affective impact of substantial emotional events. Hedonic adaptation is the supposition that there is a happiness "set point", whereby humans generally maintain a constant level of happiness throughout their lives, despite events they experience. The process of hedonic adaptation is conceptualized as a treadmill, since no matter how hard one tries to be happier, one remains in the same place.Hedonic adaptation can occur in a variety of ways. Generally, the process involves cognitive changes, such as shifting values, goals, attention and interpretation of a situation. The process of adaptation can occur through the tendency of humans to construct elaborate rationales for considering themselves deprived through a process social theorist Gregg Easterbrook calls "abundance denial". Further, neurochemical processes might possibly desensitize overstimulated hedonic pathways in the brain, which possibly prevents persistently high levels of intense positive or negative feelings.
Behavioral/psychological approach
"Hedonic treadmill" is a term coined by Brickman and Campbell in their article, "Hedonic Relativism and Planning the Good Society", describing the tendency of people to keep a fairly stable baseline level of happiness despite external events and fluctuations in demographic circumstances. In 1978 Brickman, et al., began to approach hedonic pleasure within the framework of Helson's adaptation level theory, which holds that perception of stimulation is dependent upon comparison of former stimulations. The hedonic treadmill functions similarly to most adaptations that serve to protect and enhance perception. In the case of hedonics, the sensitization or desensitization to circumstances or environment can redirect motivation. This reorientation functions to protect against complacency, but also to accept unchangeable circumstances.Frederick and Lowenstein classify three types of processes in hedonic adaptation: shifting adaptation levels, desensitization, and sensitization. Shifting adaptation levels occurs when a person experiences a shift in what is perceived as a "neutral" stimulus, but maintains sensitivity to stimulus differences. For example, if Sam gets a raise he initially feels happier, and then habituates to the larger salary and return to his happiness set point. But he is still be pleased when he gets a holiday bonus. Desensitization decreases sensitivity, which reduces sensitivity to change. Those who have lived in war zones for extended periods of time may become desensitized to the destruction that happens on a daily basis, and be less affected by the occurrence of serious injuries or losses that may once have been shocking and upsetting. Sensitization is an increase of hedonic response from continuous exposure, such as the increased pleasure and selectivity of connoisseurs for wine, or food.
Brickman, Coates, and Janoff-Bulman were among the first to investigate the hedonic treadmill in their 1978 study, "Lottery Winners and Accident Victims: Is Happiness Relative?". Lottery winners and paraplegics were compared to a control group and as predicted, comparison and habituation affected levels of happiness such that after the initial impact of the extremely positive or negative events, happiness levels typically went back to the average levels.
Brickman and Campbell originally implied that everyone returns to the same neutral set point after a significantly emotional life event. In the literature review, "Beyond the Hedonic Treadmill, Revising the Adaptation Theory of Well-Being", Diener, Lucas, and Scollon concluded that people are not hedonically neutral, and individuals have different set points that are at least partially heritable. They also concluded that individuals may have more than one happiness set point, such as a life satisfaction set point and a subjective well-being set point, and that because of this, one's level of happiness is not just one given set point but can vary within a given range. Diener and colleagues point to longitudinal and cross-sectional research to argue that happiness set point can change, and lastly that individuals vary in the rate and extent of adaptation they exhibit to change in circumstance.
Empirical studies
In a longitudinal study conducted by Mancini, Bonnano, and Clark, people showed individual differences in how they responded to significant life events, such as marriage, divorce and widowhood. They recognized that some individuals do experience substantial changes to their hedonic set point over time, though others do not, and argue that happiness set point can be relatively stable throughout the course of an individual's life, but the life satisfaction and subjective well-being set points are more variable.Similarly, the longitudinal study conducted by Fujita and Diener described the life satisfaction set point as a "soft baseline". This means that for most people, this baseline is similar to their happiness baseline. Typically, life satisfaction hovers around a set point for the majority of their lives and not change dramatically. However, for about a quarter of the population this set point is not stable, and does indeed move in response to a major life event.
Other longitudinal data has shown that subjective well-being set points do change over time, and that adaptation is not necessarily inevitable. In his archival data analysis, Lucas found evidence that it is possible for someone's subjective well-being set point to change drastically, such as in the case of individuals who acquire a severe, long term disability. However, as Diener, Lucas, and Scollon point out, the amount of fluctuation a person experiences around their set point is largely dependent on the individual's ability to adapt.
After following over a thousand sets of twins for 10 years, Lykken and Tellegen concluded that almost 50% of our happiness levels are determined by genetics. Headey and Wearing suggested that our position on the spectrum of the stable personality traits accounts for how we experience and perceive life events, and indirectly contributes to our happiness levels.
In large panel studies, divorce, death of a spouse, unemployment, disability, and similar events have been shown to change long-term subjective well-being, even though some adaptation does occur.
In the aforementioned Brickman study, researchers interviewed 22 lottery winners and 29 paraplegics to determine their change in happiness levels due to their given event. The event in the case of lottery winners had taken place between one month and one and a half years before the study, and in the case of paraplegics between a month and a year. The group of lottery winners reported being similarly happy before and after the event, and expected to have a similar level of happiness in a couple of years. They found that the paraplegics reported having a higher level of happiness in the past than the rest, a lower level of happiness at the time of the study than the rest and, surprisingly, they also expected to have similar levels of happiness than the rest in a couple of years. The paraplegics did have an initial decrease in life happiness, but they expected to eventually return to their baseline in time.
In a newer study, winning a medium-sized lottery prize had a lasting mental wellbeing effect of 1.4 GHQ points on Britons even two years after the event.
A research study in mice suggests that resilience to suffering is partly due to a decreased fear response in the amygdala and increased levels of BDNF in the brain. This 2015 research found that changing a gene in mice increased resilience to depressing and traumatizing events such as forcing the mice to swim. This could have crucial benefits for those with anxiety and PTSD.
Hippocampus volume can affect mood, hedonic setpoints, and some forms of memory. A smaller hippocampus has been linked to depression and dysthymia. Certain activities and environmental factors can reset the hedonic setpoint and also grow the hippocampus to an extent.
Lucas, Clark, Georgellis, and Diener researched changes in baseline level of well-being due to changes in marital status, the birth of first child, and the loss of employment. While they found that a negative life event can have a greater impact on a person's psychological state and happiness set point than a positive event, they concluded that people completely adapt, finally returning to their baseline level of well-being, after divorce, losing a spouse, the birth of a child, and for women losing their job. They did not find a return to baseline for marriage or for layoffs in men. This study also illustrated that the amount of adaptation depends on the individual.
Wildeman, Turney, and Schnittker studied the effects of imprisonment on one's baseline level of well-being. They researched how being in jail affects one's level of happiness both short term and long term. They found that being in prison has negative effects on one's baseline well-being; in other words one's baseline of happiness is lower in prison than when not in prison. Once people were released from prison, they were able to bounce back to their previous level of happiness.
Silver researched the effects of a traumatic accident on one's baseline level of happiness. Silver found that accident victims were able to return to a happiness set point after a period of time. For eight weeks, Silver followed accident victims who had sustained severe spinal cord injuries. About a week after their accident, Silver observed that the victims were experiencing much stronger negative emotions than positive ones. By the eighth and final week, the victims' positive emotions outweighed their negative ones. The results of this study suggest that regardless of whether the life event is significantly negative or positive, people almost always return to their happiness baseline.
Fujita and Diener studied the stability of one's level of subjective well-being over time and found that for most people, there is a relatively small range in which their level of satisfaction varies. They asked a panel of 3,608 German residents to rate their current and overall satisfaction with life on a scale of 0–10, once a year for seventeen years. Only 25% of participants exhibited shifts in their level of life satisfaction over the course of the study, with just 9% of participants having experienced significant changes. They also found that those with a higher mean level of life satisfaction had more stable levels of life satisfaction than those with lower levels of satisfaction.