Dopamine Neurons

Jonah Lehrer has written an interesting article for Seedmagazine on a “New state of mind” which only reminds me how I wish I had studied neuroscience than computer science for all these years. The paper details the research of Read Montague, director of the Human Neuroimaging Lab at Baylor College of Medicine in Houston.

In early studies of monkeys anticipating the supply of juice following a specific audio tone he says that it’s all about expectation:

Dopamine neurons constantly generate patterns based upon experience: If this, then that. …  And if these predictions ever prove incorrect, then the neurons immediately readjust their expectations. The discrepancy is internalized; the anomaly is remembered. “The accuracy comes from the mismatch,” Montague says. “You learn how the world works by focusing on the prediction errors, on the events that you didn’t expect.” Our knowledge, in other words, emerges from our cellular mistakes. The brain learns how to be right by focusing on what it got wrong.

Now this is entirely consistent with Dave Snowden’s view that we learn more from negative stories (things that go wrong) than we do from hearing of another persons success.

Then moving onto why we chase ideas:

“One of the distinguishing traits of human beings is that we chase ideas, not just primary rewards,” Montague says. “What other animal goes on hunger strike? Or abstains from sex? Or blows itself up in a cafe in the name of God?” These unique aspects of human cognition seem impossible to explain with neurons that track and predict rewards. After all, these behaviors involve the rejection of rewards: We are shrugging off tempting treats because of some abstract belief or goal.

“The guy who’s on hunger strike for some political cause is still relying on his midbrain dopamine neurons, just like a monkey getting a treat,” Montague says. “His brain simply values the cause more than it values dinner.” According to Montague, the reason abstract thoughts can be so rewarding, is that the brain relies on a common neural currency for evaluating alternatives.

Again, I can see something in this about the human weakness (?) of cognitive bias and making decisions on gut instinct and first-fit rather than looking at all the alternatives and making complete sense of the situation we might face.

The final part of this paper certainly had my dopamine neurones firing as it tempts us with:

Montague’s experiments take advantage of his unique fMRI setup. He has four people negotiate with one another as they decide how much to offer someone else during an investing game. While the group is bickering, Montague is monitoring the brain activity of everyone involved. He’s also infiltrated the group with a computer player that has been programmed to act just like a person with borderline personality disorder. The purpose of this particular experiment is to see how “one bad apple” can lead perfect strangers to also act badly. While Montague isn’t ready to share the results — he’s still gathering data — what he’s found so far is, he says, “stunning, shocking even…. For me the lesson has been that people act very badly in groups. And now we can see why.”

So what are the findings?, does power corrupt? does evil always win over good? will it give us a possible method of intervention or simply allows in hindsight to identify the ‘one bad apple’ and how long before we find out? and why do I so enjoy the deconstruction of behaviour down to decisions right down to which neuron and which specific chemical?


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