Germs, dirt, and relationships: why people may not want what they need (by guest blogger Dan Haybron)

It is widely thought that happiness depends on getting what you want. Indeed, the switch in economics from happiness to preference satisfaction as the standard of utility was originally based on the idea that the latter is a good proxy for the former: happiness is a function of the extent to which you get what you want. Even if you don‘t believe that, you might accept this weaker claim: basic human needs will normally be accompanied by desires for goods that tend to satisfy those needs; and the strength of those desires will reflect the importance of the needs. Thus human psychological needs will be reflected in people‘s motives. Call this the Needs-Motivation Congruency Thesis (NMCT). Hunger would be a typical example: we strongly desire food because we strongly need food (not just for happiness, of course).

I see no reason to believe that this is true. Among other things, there‘s an in-principle reason we should not expect the NMCT to hold: common human motivational tendencies will largely reflect the needs of our evolutionary ancestors. We want food because such a desire contributed to inclusive fitness: if you didn‘t have that desire, your genes didn‘t go very far. But here‘s another physiological need humans
apparently have: we seem to need early exposure to germs and dirt. Without it, we develop various allergies and immune deficiencies. Yet most people don‘t have a particular attraction to germs and dirt (as such!). If anything, it‘s the reverse. Why? Because such a desire would have done nothing for inclusive fitness when humans evolved: you couldn‘t avoid encounters with lots of germs and dirt. If anything, it
would have been adaptive to limit exposure to such things. So we need a dirty childhood, but don‘t want one; kids are happy to sit in an anti-septic environment playing video games all day, puffing on albuterol inhalers.

The same thing may happen with happiness: we may need certain things for happiness but either have no particular desire for them, or our desire for them is weak compared to the need. Relationships may be an example. Good relationships are the strongest known source of happiness, and are clearly a deep psychological need for human beings. Now normal people do, clearly, desire social relationships. Yet many
if not most of us choose to live in ways that compromise our relationships, often to the net detriment of our happiness. E.g., people often choose lucrative jobs at the expense of time with friends and family. It is easy to see how a strong desire for wealth and status might have been adaptive for early humans, whereas we probably
didn‘t need proportionately strong desires for friendship and family: you got those automatically. So our desire for wealth and status trumps our desire for a more important need, good relationships.

Next up: biophilia as another possible counterexample to the NMCT.