Writing about those New Year's resolutions, Jonah Lehrer asks why human will power is so feeble:
Consider this experiment, led by Baba Shiv, a behavioral economist at Stanford University. He recruited several dozen undergraduates and divided them into two groups. One group was given a two-digit number to remember, while the second group was given a seven-digit number. Then, they were told to walk down the hall, where they were presented with two different snack options: a slice of chocolate cake or a bowl of fruit salad.
Here’s where the results get weird. The students with seven digits to remember were nearly twice as likely to choose the cake as students given two digits. The reason, according to Shiv, is that all those extra numbers took up valuable space in the brain – they were a 'cognitive load' – making it that much harder to resist a decadent dessert. In other words, willpower is so weak, and the conscious mind is so overtaxed, that all it takes is five extra bits of information before it becomes impossible for the brain to resist a piece of cake.
What's limited, as Lehrer explains, is not willpower, but attention. Direct it elsewhere and the odds that you will forsake that extra piece of cake go up significantly. Read more about this willpower trick here, and check out that first kid's expression in the video above. He's a gonner.