His finding has been replicated repeatedly: resolutions work. And it suggests that rather than being single-minded, as economists have traditionally believed, many of us are better thought of as having at least two minds, each fighting for control. One might be the saver, the other the spender; one the lifter, the other the leaner; one the dieter, the other the eater....
Economics has traditionally explained away what appear to be two separate selves by saying each of us is one self with stable preferences moderated by a discount rate. Because we care most about the present we "discount" whatever good or bad things are likely to happen in the future when comparing them to the good or bad things we are facing now. We are said to have a constant discount rate of about 8 per cent per year....
But the explanation doesn't stand up. Rather than being constant, our discount rate seems to climb the closer we get to the choice we have to make.
Ask someone today to choose between working seven hours on April 1 or eight hours on April 15 and that person will almost certainly choose the easier day on April 1. But ask again when April 1 arrives and the same person will almost certainly choose the harder day in a fortnight's time.
It seems that our short term self is always in a battle with out long term self.
The two fight it out. There's no single "self" always in command....
If they are right it explains the success of resolutions - they are a tool the long-term self can use to trap the short-term self into acting.
And it explains why certain types of resolutions are more likely to succeed than others - those that are specific and are made in public with no room for backing out.
His advice for tonight is to eschew vague resolutions and go for absolutes: "Just as it may be easier to ban nuclear weapons from the battlefield in toto than through carefully graduated specifications on their use, zero is a more enforceable limit on cigarettes or chewing gum than some flexible quantitative ration."
And say it out loud. Lock yourself in. Surprise yourself.