a blog with cultural bulimia.

Monday, December 04, 2006

Me & My Selves.

From yesterday's New York Times:

"You might naïvely imagine that you are one person, the same entity from day to day. To the 18th-century philosopher David Hume, however, the idea of a permanent “I” was a fiction. Our mind, Hume wrote, “is nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement.” According to this way of thinking, the self that inhabits your body today is only similar to, not identical with, the self that is going to inhabit your body tomorrow. And the self that will inhabit your body decades hence? A virtual stranger.

The idea of multiple selves may seem like a stoner’s fantasy, but economists who study human decision-making have found it surprisingly useful. Consider: Most people, if given a choice today between doing seven hours of irksome work on May 1, 2007, versus eight hours on May 15, 2007, opt for the former. When May 1 arrives, however, they will find that their preference has flipped: they now wish to put off the work for a couple of weeks, even at the cost of having to do the extra hour’s worth. Why this inconsistency, if the self calling the shots is one and the same?

Further evidence for the fragmented self comes from neuroscience. Brain scans show that the emotional part of the brain, the limbic system, is especially active when the prospect of immediate gratification presents itself. But choice among longer-term options triggers more activity in the “reasoning” part of the brain, located (suitably enough) higher up in the cortex. Now suppose you’re tempted by a diet-violating Twinkie. Which part of your brain — the shortsighted emotional part or the farsighted reasoning part — gets to be the decider? There may be no built-in hierarchy here, just two autonomous brain modules in competition. That is why you might find yourself eating the Twinkie even while knowing it’s bad for you. (A similar disconnect between two parts of your brain occurs when a visual illusion doesn’t go away even after you learn it’s an illusion.)

The short-run self cares only about the present. It is perfectly happy to indulge today and offload the costs onto future selves. For example, recent studies show that teenage smokers do not underestimate the risk of getting lung cancer as an adult (if anything, they tend to overestimate it); they simply don’t mind making the future self suffer for the pleasure of the moment. The long-run self may deplore this ruinous behavior, but its prudent resolutions are continually ignored. Yet it can enforce its will indirectly by shaping the environment to constrain some short-run selves from exploiting others — by, say, putting a time lock on the refrigerator."