Friday, January 19, 2007

Shopping Centers in the Brain

This is the title of revew by Dagher in the Jan 4 issue of Neuron of an article by Knutson et al. in the same issue that tests a neuroeconomic theory that is well suited to investigation by fMRI: that potential gains and losses are evaluated independently (i.e., by different neural systems), and, more specifically, that financial decisions are guided by emotional biases, which are presumably related to neural activity in brain regions involved in the processing of positive and negative emotion.

From the article's abstract: "Consistent with neuroimaging evidence suggesting that distinct circuits anticipate gain and loss, product preference activated the nucleus accumbens (NAcc), while excessive prices activated the insula and deactivated the mesial prefrontal cortex (MPFC) prior to the purchase decision. Activity from each of these regions independently predicted immediately subsequent purchases above and beyond self-report variables. These findings suggest that activation of distinct neural circuits related to anticipatory affect precedes and supports consumers' purchasing decisions."

From Knutson: “It was amazing to be able to see brain activity seconds before a decision and predict whether the person would buy it or not.”

NOTE: I'm not including a graphic of the MRI data from the article, as I have been doing in many posts like this, because they don't give you much you couldn't learn from simply entering the name of brain structures mentioned (insula, nucleus accumbens) in Google Images and getting even more information on their general context.

Another point is that articles like this are trendy and get popular press, but one reasonable reaction is "Well, duh! What did you expect?" Brain changes correlate with behavior changes! Of course, the slicing and dicing of what happens where is a necessary part of describing the machine, and there is a sense of relief that discrete behaviors correlate with discrete regions of brain activity. It could have looked like undifferentiated mush, everything happening everywhere. And, some lists of the multiple areas suggested to be implicated in consciousness begin to look like this.

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