These measures gauge the amount of time a person experiences positive affect versus negative affect. Frequency measures of affect avoid some of the issues of scale norming. In other words, they might subconsciously rate themselves relative to other amputees rather than to the average healthy person. One alternative explanation for why people who have undergone a major life change (e.g., amputation) are not as unhappy as we might expect is that they might normalize the scale. For example, one person may interpret a 7 as being the absolute highest level of happiness a person could possibly achieve, whereas another may interpret a 7 as manifesting a high level of happiness in comparison to the average person.

Given the subjectivity of this approach, people may interpret the scale differently. Researchers generally measure happiness by asking participants to indicate their overall level of happiness on a scale from low to high (e.g., 1 to 7). One concern is whether people truly adapt to life changes, or if the evident decline in well-being is a result of scale norming ( Frederick & Loewenstein, 1999).

The literature on hedonic adaptation involves several methodological issues. Thus, although desensitization and hedonic adaptation share certain characteristics, hedonic adaptation cannot be explained as merely desensitization to a stimulus. People who are desensitized would not notice the difference between their current 400-square-foot apartment and the 450-square-foot apartment next door, nor would they be motivated to attempt to substitute their apartment for the larger one. It is characterized by reduced sensitivity toward differences in a stimulus. Desensitization, by contrast, reduces the affective intensity of an event more generally. He may even become motivated to try to switch apartments. However, after he adapts to his current apartment, the apartment next door begins to appear much larger and more favorable in comparison.

For example, a person moving into a 400-square-foot apartment may not initially observe much of a difference between his apartment and the 450-square-foot apartment next door. Consequently, people become more sensitive to differences in a stimulus. However, hedonic adaptation diminishes that intensity by shifting the perceptions of the positivity or negativity of a stimulus, such that what was initially observed as positive or negative becomes neutral ( Frederick & Loewenstein, 1999). Both hedonic adaptation and desensitization reduce the emotional intensity of an event.

Because hedonic adaptation involves becoming accustomed to a stimulus, it is often confused with a similar concept, desensitization. Hedonic adaptation is similar to, yet distinct from, several other related processes. Sheldon, in Stability of Happiness, 2014 What Is Not Hedonic Adaptation?