Zimmer: There is a lot of work lately in understanding how perception translates into action, making sense of what goes on when we make a decision to do something.
Wang: Some neuroscientists who are studying these processes are interested in the idea that perhaps you could have a brain center that gathers evidence and reaches a threshold for making a commitment. There might be another brain center that expresses confidence in the decision or even the very awareness of the decision.
Here’s an example that many of you may have encountered from everyday life. You may be presented with a dilemma—say, whether to take a job in a new city. The pioneering psychologist Amos Tversky once did an informal survey over a period of years, asking people how confident they were that they were going to take such a job offer. There was a tendency for people to underestimate their own certainty in the decision. People would say things like “Well, I’m not sure. I’m inclined to probably take it, but I’m still thinking about it.” What Tversky found was that people almost always went and took the job.
So you can be pretty committed to a decision yet be unaware of it. In fact, if you are very close to someone—let’s say your spouse—he or she might be aware of your decisions before you yourself are. That’s an example in which your mental processes may not be available to you, but they are available to someone who knows you well. So something that we might imagine being integral to our consciousness is in fact composed of components that are not explicitly accessible to us.
Zimmer: Mike, you’ve been working with legal scholars to try to bring insights from neuroscience to the law. Are you making progress with that?
Gazzaniga: It’s a large project in which we’re trying to look at the impact of neuroscience on our sense of justice. A way to summarize the project is to say what one of the philosophers said in the study groups:? “We are the law.” It means that how we think about ourselves pretty much sets up the framework for how we deal with cheaters, people who are not doing their job, people who do harm, and all the rest of it.
When you have this basic insight, then you realize that new knowledge about who we are is going to change how we think about the law. How we think of ourselves, how we should think about punishment and retribution, and how we might want to change the way we deal with those things are the large questions that we’re considering.
The more immediate issue is that neuroscience is everywhere. So should it be in the courtroom? Is having a scan of somebody’s brain during a trial helpful? Lawyers like to put it in terms of “Is it prejudicial or is it probative?” Maybe just having a picture up of a brain prejudices the jury to think that we really understand something when actually all it is is a picture through a time point that may not in fact be telling you much at all. So one of the objectives of the legal project is to look at the issue of how much neuroscience should be in the courtroom and how much of it should not.
The field is vast, and we’re trying to narrow it down to a few questions. Then we’ll have a unique union of neuroscientists working with lawyers and jurists to sharpen a question by carrying out actual particular experiments.
Audience member?: Picking up on that theme of morality and responsibility, what goes on in the brain when someone can’t control their anger properly?
Saxe: One really interesting discovery about the brain is that one of the major ways it works is by generating all the possible responses to a situation and then inhibiting the ones that you don’t want.
When there’s a cup in front of me or a comb in front of me, most of the time I don’t drink from the cup, and most of the time I don’t pick up the comb and comb my hair. Especially I don’t comb my hair if it’s an inappropriate context, and I don’t drink from the cup if it’s somebody else’s cup.
You might think we generate the plan for how to reach for the cup and drink from it only if that is something we have decided to do. But it turns out, actually, that our brains are constructing representations for all the possible actions with all the possible objects in front of us and then tamping them down. You can see this in patients who have lost some inhibitory controls because they’ve had damage to their frontal lobes. You get what’s called utilization behaviors. You get people who, literally anytime you put a comb in front of them, will start combing their hair just because there’s a comb. They’ll use it. If you put a glass in front of them they’ll drink from it.
I think that’s probably also true of our emotional responses. There’s much more being generated and then tamped down. So one really important function our brain provides us is the ability to not act on all the possibilities that it’s generating.
Levitin: One of the most interesting and counterintuitive things I learned in my training is that what differentiates the human brain from those of other species is the huge, enormous size of our prefrontal cortex. You would think that what all this prefrontal cortex real estate would do for us is allow us to do all these wonderful things like paint and make music and speak and build churches and cities and schools and have systems of justice, but at an anatomical level one of its most distinguishing characteristics is that it’s full of inhibitory circuits.
Wang: The prefrontal cortex is often thought of as being responsible for carrying out executive functions: performing the considerations that come before action, planning for the future, acting on those plans, perhaps exerting will to make a good impression on someone in a job interview or in some other kind of controlled situation.
I feel tempted after this very cerebral discussion to give you a piece of practical advice. These acts of willpower and control in the prefrontal cortex are things that you can exercise like a muscle. There are mental resources. The brain changes in response to the environment, and you can in fact increase the amount of willpower you have by practicing something. As an example, if I give you a bunch of cookies to eat and then I give you an impossible puzzle to solve, you’ll persist in that puzzle for some time.
Now, if instead of giving you cookies I give you a bowl of radishes to eat—most people don’t like raw radishes—and then give you the impossible puzzle, you’ll persist on the puzzle for about eight minutes less. There appears to be some finite mental resource of willpower. You willed yourself to eat the radishes and you depleted that resource. Psychologists refer to this phenomenon as ego depletion. You have less willpower for the next thing.
But it turns out you can actually build up willpower like a muscle if you can do something that requires effort of will—something as silly as brushing your teeth with your nondominant hand. If you brush your teeth with your nondominant hand for several weeks, you increase this reserve pool of mental something. I’m not going to say what that something is because it’s not known, but that mental something is available for other tasks. You can actually build up whatever it is that is responsible for willpower.
So this business of planning for action and all the things that come before action turn out, like many mental capacities, to be a thing that you can practice at and improve.