It's former Times op-ed columnist John Tierney's first piece since switching over to the Science section, and he uses the debut to investigate why he dropped two grand on Christmas presents this year. Actually, it's a well-written examination of why the brain urges you to spend money on useless things. Tierney, doing a bit of participatory journalism, gets a brain scan which reveals an interesting fact about his own neural instincts. We've reproduced it here; click to enlarge.

The Voices in My Head Say 'Buy It!' Why Argue? [NYT]