On the heels of a post I did at The Scientist (“Amazing Rats”), where I proposed a new model of intelligence based on a animal’s ability to solve problems rather than its communication skill, I read a blog post by Jonah Lehrer at The Frontal Cortex where he gives his take on what intelligence really means. Rather than smarts merely defined by how many facts someone can cram into their heads, Lehrer argues that a better measure of intelligence is to look at how well people (or animals) can shift their selective attention.  Facts are just facts, but the intelligent being can manipulate and organize the information for the task at hand, which places a high demand on the attention circuits in the brain.

Lehrer cites a study by Walter Mischel, which studied a group of children that had a marshmallow placed in front of them.  The kids were told that they could have the marshmallow now, or wait 15 minutes and get two marshmallows.  According to Lehrer, those children that were able to wait for the bigger reward payout had better SAT scores, were better behaved, and less stressed than their impulsive counterparts.

Mischel’s study is a classic test for discounting of delayed rewards, and I’m not surprised that the kids that were able to wait a short period of time for the bigger reward ultimately did better than those that couldn’t.  But are the kids that could wait more intelligent, or is there something else going on with the kids that cracked?

Numerous studies have shown that people prone to addiction continually discount delayed rewards.  They’re impulsive.  They can’t see past the immediate pleasure of the reward.

Defects in the dopamine reward system (e.g. addiction) interfere with other circuits in the brain.  Therefore, it doesn’t surprise me that very intelligent addicts make unwise decisions while seeking their next high.

I’m not saying all the kids in Mischel’s study who impulsively took the first marshmallow as a reward were all addicts.  But as Lehrer pointed out, these kids ended up more stressed out and with more behavioral problems than other children, which says there’s more to the story than simply an intelligence difference.