Bentham himself explicitly rejected this possibility:
Take just three examples:
1. Preferences adapt to circumstances; this is one way in which the worst-off people adapt to their conditions. As a result, the battered slave, the hopeless destitute might feel happy - happier indeed than the dissatisfied wealthy. Heeding self-reported happiness might, therefore, perpetuate injustice.
This is no mere philosophic possibility. Just contrast the clamour for cuts in inheritance tax a few years ago to the silence with which young people are greeting their worsening job prospects.
2. We fail to foresee (pdf) that this adaptation will occur. As a result, we work too hard and spend too much, as we over-estimate the extent to which more money and goods will make us happy, and spend too much time watching TV or travelling to work.
3. The endowment effect and status quo bias. We over-value things just because we have them, and so fear change more than we should.
These three biases all point in the same direction. They suggest that giving weight to self-reported happiness would help entrench the status quo. They also suggest that many policies that might increase happiness - such as increased aid to the third world, or policies to fight unemployment and mental illness (to take examples from Layard’s book) - won’t have democratic support.
Layard suggests that the solution to this is better education. But this is only a long-term remedy. In the short-term - by which I mean many, many years - we have a dilemma. There’s a trade-off between self-reported happiness and democracy on the one hand, and “genuine” well-being on the other.