It looks like D&D was right after all: willpower is an attribute. John Tierney has a great article about decisions and how it takes literal willpower to exercise them. Making a decision has a mental cost that depletes a reserve that’s recharged temporarily by glucose. More difficult decisions have higher mental costs, and this can be used by merchants who can manipulate consumer choices with the order in which they present choices when making purchases. Consumers who have depleted their willpower reserve will tend to conserve what they have left by going with “default” options which merchants have priced higher than non-default options. Judges are not immune to decision fatigue either.
One of the most ironic and sad results is the difficulty of sticking to a diet. Sugar is the only thing that staves off decision fatigue. But every time the dieter denies himself food, his willpower decreases and his body will eventually demand sugar until it gets the real stuff as it isn’t fooled by artificial sweeteners. God must hate fat people too.
I find this result so compelling, that I’m going to be thinking about how to counter it in daily life. Avoid making important decisions late in the day or if it’s unavoidable, make it with some amount of sugar in your system. Try to reduce the number of decisions you have to make by forcing some of them on yourself. Working out with a friend at a scheduled time as a way of avoiding a daily decision is something I’ve done before without realizing exactly how the calculation worked.
The research again reminds me of the marshmallow test. Some people will naturally have stronger willpower than others and those people will be more likely to have positive life outcomes.