Suppose you became paraplegic. Initially, you would experience a lot of unhappiness. And suppose that no neurological improvement was possible. Nevertheless, over time, you would most likely recover a lot of your sense of well-being. What's going on?
A cool article by Bradford and Dolan (Journal of Health Economics 29 (2010) 811–820) seeks to model how this works. Standard economic models take our preferences as fixed, so that if we experience a loss of mobility, we judge this to be worse and experience subjective unhappiness. They argue, instead, that our prefences are themselves a matter of choice and, therefore, adapted to our situations.
The idea is that there are many domains of life, in fact more than we can actually attend to. When you can attend to a domain, you make things better there, and generate well-being. However, maintaining attention on any one domain takes effort, and shifting to an new domain takes even more. However, if things start going poorly in one domain, it's worth it to shift your attention to some area of life where you can produce well-being for yourself more efficiently. Can't play basketball anymore? Try chess. The adaptation isn't immediate, because it takes effort. But over time, you get back most of your well-being. This is the blessing of adaptive preferences.
The curse, however, that the adaptive nature of preferences means that sometimes it is easier to just 'settle' your losses by shifting your preferences instead of making a difficulty change. Suppose that you lost enjoyment from basketball because you gained 50 lbs and couldn't run the floor. Bradford and Dolan:
...individuals may ultimately fail to reduce BMI (even if it would lead to significant changes in the utility domains) because they may find it less costly to adapt to lower values of some utility domains. That is, the opportunity cost of reducing one or more of the utility weights on the domains where BMI plays a large role may be lower than the opportunity cost of actually changing BMI.
You adapt to your gain in BMI by changing your preferences such that you no longer care about things that require low BMI and care about other things instead. You gain compensatory well-being in those other domains. The problem, though, is that in effect your personal technology for producing well-being (health, as indexed by BMI), has deteriorated, and you have adapted to that loss instead of fixing it. Put it in child health terms: the more time kids invest in sedentary games, the heavier they get, the heavier they get, the more time they invest in sedentary games. Adaptation can become a vicious cycle, and this is the curse of adaptive preferences.