by Patrick Appel

Jonah Lehrer sprinkles a few caveats throughout Emily Yoffe's article on information addiction:

I think it's worth qualifying this "information equals crack" meme. The brain, as we all know, is not an indiscriminate curiosity machine. Most people don't want to know more about quantum mechanics, or the actual details of health care reform, or what's happening in the Afghanistan presidential campaign. In other words, our craving for news tends towards the local and the personal - our curiosity is circumscribed. Why might this be? The answer, I think, has to do with the molecular details of how information triggers rewards.

This isn't the post for another summary of computational models of dopamine activity - see here and here, if you're interested - but suffice to say that our brain cells are finely tuned to want more information about stuff which they already know. In essence, these cells work by constantly striving to reduce their "prediction-error signal," which is the gap between what these cells expect to happen and what actually occurs. If a monkey has been trained to get a squirt of juice everytime a bell is rung, then these dopaminergic cells quickly learn that the bell predicts the sweet reward. As a result, they want more information about that specific rewarding stimulus. What, for instance, predicts the bell? Maybe the scientist flicks a switch before ringing the bell? Or maybe he scratches his nose? Or maybe he simply enters the room? What numerous experiments have found is that our dopamine neurons aren't interested in responding to the reward itself - instead, they want to find the first reliable bit of information that predicts the reward. This is why we crave new facts: they are means of updating our old facts, of extending our cognitive models forward in time.

I read Lehrer's new book, How We Decide, a few weeks ago. I highly recommend it to anyone interested in metacognition or the tension between reason and emotion.

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