A reader asks:
What’s the hardest question you’ve gotten about the new book? Is there one you were totally unprepared to answer?
This is a slightly embarrassing confession, but one of the most difficult questions I’ve been asked is also one of the most obvious. It goes something like this:
“What practical knowledge have we gained by looking at decision-making in the brain that we didn’t already have, either through introspection or behavioral studies?”
When I was first asked this question, I think I muttered something about the virtue of curiosity, breaking open the black box and fulfilling that ancient dictum “know thyself”. In other words, I completely avoided the query, like a slippery politician. While I think those are all valid motivations for neuroscience – there is something epic about trying to understand the three pounds of gelatinous flesh inside the skull – they also aren’t particularly practical.
And I think it’s also worth pointing out (as I have before) that a tremendous amount of modern neuroscientific ideas have been presciently anticipated by everyone from David Hume to William James to Aristotle to Virginia Woolf. This shouldn’t be too surprising – introspection is a powerful investigative tool. David Hume, for instance, summarizes an awful lot of recent work on the importance of emotional signals during decision-making with this famous line: “Reason is and ought to be the slave of the passions and can never pretend to any other office than to serve and obey them.”
So what’s the added benefit of neuroscientific explanations? If Hume was right, and James was such a genius, and we can learn so much from “mere” behavioral studies, then why bother with the amygdala or dopamine?
The best answer, I think, is that learning about the brain can help constrain our theories. We haven’t decoded the cortex or solved human nature – we’re not even close – but we can begin to narrow the space of possible theories. We know, for instance, that the rational agent model of Homo Economicus isn’t particularly accurate, at least from the perspective of the brain, and that the deliberative prefrontal cortex is often out-shouted by emotional brain areas like the nucleus accumbens, insula, etc. This supports, of course, lots of observational studies that demonstrate that people rarely rely on explicit calculations of utility (or explicit calculations of anything, really) when making decisions. The anatomical details, in other words, can help settle the argument.
Now this might seem rather underwhelming – all those pretty fMRI pictures just constrain our pre-existing theories? – but I actually think it’s rather essential. Consider Freud. The man had an uncanny talent for inventing elegant theories. He was a hypothesis machine, churning out one fantastic sounding idea after another. But which of these ideas are true?
Here’s where neuroscience comes to the rescue. I think time and experiments have redeemed some of Freud’s fundamental theories – the unconscious drives much of our behavior, dreams aren’t random narratives, but actually regurgitate scenes and snippets from daily life, etc. – while other Freudian theories have largely fallen flat (your Mom probably isn’t responsible for most of your neuroses). We can take something as vague as the id and began shackling it to particular brain regions, like the aforementioned amygdala. (The prefrontal cortex is some fusion of the ego and super-ego.) By recording from hippocampal cells in the rat, scientists can begin to decode the function of dreams, and see how they’re a crucial component of memory consolidation. And so on. The point is that, while all of Freud’s theories might sound convincing, only a few of them are actually correct. In this sense, neuroscience is what helps us separate the beautiful theory from the definite truth.
How would you answer the question?