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My Immature Brain Made Me Do It?

Gregory S. Berns — Wed, 21 Oct 2009 02:14:45 +0000

On November 9th, 2009 the Supreme Court will hear arguments on whether the 8th amendment's ban on cruel and unusual punishment prohibits courts from sentencing children to life without the possibility of parole for the commission of a non-homicide. Joe Sullivan and Terrance Graham were 13 and 17 years old respectively at the time of their crimes. Although their crimes were violent, no one was killed. Yet they were both sentenced to life without parole by Florida judges. The question before the Court is whether the 8th amendment prevents courts from locking up children and throwing away the key.

Common standards of decency and the fact that adults rarely get life without parole for the same crimes make a strong case for the petitioners. But Sullivan and Graham are not really the ones on trial. The elephant in the room, and the thing that the Court has taken deliberate steps to leave out of its rulings in the past, is the human brain. The last time around, in Roper V. Simmons (2005), the Court held that it is unconstitutional to execute someone for committing a crime while under the age of 18. Despite numerous briefs submitted by mental health advocacy groups suggesting that the brain is not fully mature until the mid-20's, the Court wisely did not use this information in its ruling.

Come November, the Court should once again ignore the growing drumbeat to blame the immature brain. Hopefully, the Court will leave neuroscience out of its decision.

When you take an MRI of a person's brain, it is easy to distinguish gray and white matter. A wealth of neuroscience data has shown that these two parts of the brain change during development from childhood to adulthood. The density of gray matter appears to decline through adolescence in a process known as pruning. Although not well understood, it is believed that pruning allows the brain to function more efficiently. White matter, which contains the connections between neurons, gets its name from a waxy substance called myelin. During adolescence, the myelin becomes gets denser and white matter more organized, which speeds up information transmission throughout the brain.

These developmental changes occur at different rates in different parts of the brain. Everyone has heard by now that the frontal lobes are the last parts of the brain to mature, not reaching their adult form until the mid-20s. It is precisely this observation that many have seized upon as an explanation for why teenagers make bad decisions. The immature brain has been offered as an explanation for why teenagers are more impulsive and why they are more sensation seeking than adults. According to briefs submitted to the Court, the immature brain means that adolescents are less responsible for their actions as adults (ABA briefs here).

But there are serious flaws with the "immature brain made me do it" argument. In fact, my group recently published a study calling this argument into question (PLoS One, 2009, or the Scientific American article about it). All of the neuroscience findings cited in the briefs rely on a correlation of brain structure with either age or a measurement of cognitive function. Correlation means that you take one measurement and see how it changes with some other measurement. While on average, these conclusions are statistically valid, there is too much variation from one person to another to draw conclusions about any one individual. But you won't find individual variability mentioned in any of these briefs.

In fact, any measurement we can make on the brain can only account, at most, for 30% of the differences in a particular behavior from one person to another. This means that brain data cannot account for 70% of what people do. The correlations with age are no better. It's really no different than the growth charts that pediatricians use. These charts show that children get taller as they get older. But try using a growth chart in reverse. Could you determine a child's age from their height? Would you be willing to stake the child's life on that estimate?

The brain data cut both ways. If the Court invokes neuroscience, it opens a floodgate for MRIs in the judicial system. It would become necessary to perform MRIs on every child defendant to determine if their brains were sufficiently mature to stand trial, or be punished, as an adult. What should be done with a child who has an unusually mature brain for their age? Or an adult with an immature-looking brain?

And then there is the problem of the aged adult. By age 70, most people will have lost about 8% of their youthful gray and white matter. Using the same logic, it would be considered cruel and unusual punishment to sentence older adults to life without parole. Anyone for an 8th amendment appeal by Bernie Madoff?

The Stupidity of Crowds

Gregory S. Berns — Tue, 23 Sep 2008 13:43:48 +0000

Like many, I've been disturbed by the roiling of the financial markets and the sheeplike stampede to let the Treasury bail out the banks. Although worrisome in its own right, this is a topic for a different blog (one that I wrote about six months ago). No, what really has me freaked out is the gas panic going on in metro Atlanta, where I live.

As near as I can tell, this is a local phenomenon. Atlanta has a long history of, well, acting stupid when something even remotely out of the ordinary threatens the status quo. We get a snowstorm about every three years, but when it does snow you can count on the grocery stores being cleared of milk and bread. Nevermind the fact that snow only stays on the ground a day or two.

It started with Hurricane Ike. Rumors of a disruption in the gas supply caused people to top off their tanks. This, in turn, led to a few gas stations to running dry. The empty pumps freaked out more people, causing even more folks to top off the tanks and now setting off something just short of a full fledged panic. All the gas stations in my neighborhood ran dry this weekend. A few miles away, the one remaining station that did have gas had a line of cars that ran twenty deep.

Sadly, his herd behavior is the norm not only for sheep, but for humans. We evolved in social groups, and as a result, our brains are hardwired to place great importance on what other people think. When we see a group of people doing something, our brains are wired to disregard our own perceptions and accept, lock-stock-and-barrel, what everyone else is doing. Fortunately, we have a reasonably active prefrontal cortex that can override this. Sadly, I see little evidence of prefrontal activity in either metro Atlanta or the finance sector (and forget about Washington).

What can you do? I gained some insight into this problem several years ago when my research group performed an fMRI study of social conformity. We recreated a version of the famous Asch experiment of the 1950s and used fMRI to determine how a group changes an individual’s perception of the world. Two things emerged from the study. First, when individuals conform to a group's opinion, even when the group is wrong, we observe changes in perceptual circuits in the brain, suggesting that groups change the way we see the world. Second, when an individual stands up against the group, we observed strong activation in the amygdala, a structure closely associated with fear. All this tells me that not only are our brains not wired for truly independent thought, but it takes a huge amount of effort to overcome the fear of standing up for one's own beliefs and speaking out.

The silver lining to this story is that the amygdala response disappears when even a small minority speaks up. All it takes is the recruitment of one like-minded individual to tamp down this fear response.

So there it is. I'm speaking out against group stupidity. Join me.

Disclaimer: I am also plugging my new book, Iconoclast: A Neuroscientist Reveals How to Think Differently (Harvard Business Press, 2008).

Money and Happiness - The Debate that Won't Go Away

Gregory S. Berns — Wed, 16 Apr 2008 13:57:12 +0000

On the front page of the business section of the New York Times today, David Leonhardt reports on a recent study about the relationship of money and happiness. Personally, I love this debate. The “can money buy happiness” question seems to stick around as long as the nature versus nurture question. The article is about a new analysis by Betsey Stevenson and Justin Wolfers on the relationship of per capita GDP and average life satisfaction for most of the countries in the world. Unlike previous analyses, Stevenson and Wolfers find that there is, indeed, a positive relationship between per capita GDP and life satisfaction. This finding seems to rebut the famous Easterlin paradox of the '70s that suggested no such relationship.

So what's really going on? A closer examination of the data shows that even though there is a weak correlation between money and happiness, there is still a lot of variability from one country to another. Take a per capita GDP of $8,000, and you see that Brazilians are twice as happy as Bulgarians, both of which have this average level of income. There must be other factors in addition to money that account for happiness.

But one thing that money does do that seems to never make it into these discussions is the ability to buy options. Money gives you choices, even if you don’t act on them. And that is a comforting position to be in. It's not the material goods and services that money buys that seems to make people happy. Instead, it's the ability of money to buffer one against the misfortunes of life and to create opportunities to do new and different things. As I alluded to in a previous post, hope drives people's decisions – specifically the hope that the future will be better than the present -- and money in the bank is a good hedge against the future. Paradoxically, credit cards do the same thing by borrowing against the future. I wonder what the happiness graph would like if it were plotted against per capita debt.

The Technology of Mind Reading

Gregory S. Berns — Fri, 21 Mar 2008 16:42:58 +0000

I read a fascinating fMRI study published in the 20 March 2008 issue of Nature. The study is titled, "Identifying natural images from human brain activity" and was performed by a group at UC Berkeley. While in the scanner, subjects were shown a series of natural scenes, like the one shown here.

Seems fairly simple. Using fMRI, the investigators acquired a template response from each subject's visual cortex and then used this template to "decode" the brain's response to novel images.

Without going into the details of how they did this, in one subject the technique correctly identified 110 out of 120 images (92%) that the individual was viewing.

Think about this. Simply by scanning the visual cortex of an individual with fMRI and using a fairly straightforward computer algorithm, the investigators were able to determine with a high degree of accuracy what the person was looking at. This is about as close to mind-reading as it gets.

Of course, there are a few caveats. The way the experiment was setup meant that the algorithm simply had to take the brain activity and pick from a known set of images which one matched best. This is not quite the same as taking brain activity and reconstructing, de novo, what the person was seeing. But it is the first step. Surely with a large enough library of images this could be done.

What intrigues me even more is the possibility of using this technique in the absence of visual stimulation. Much of what we know about imagination suggests that mental imagery utilizes the same brain machinery as visual perception, so it might be possible to use this technique to decode thought in the absence of stimulation.

Bear Stearns and the Biology of Hope: Part I

Gregory S. Berns — Mon, 17 Mar 2008 14:24:21 +0000

Working throughout the weekend, the Fed helped broker a deal to bail out Bear Stearns. On the verge of bankruptcy, Bear Stearns will be acquired by J.P. Morgan for the bargain basement price of $270 million. Clearly, the Fed was hoping to stanch the hemorrhaging on Wall Street. But it had already rendered its judgment on Bear Stearns last Friday when its market value collapsed.

While the Fed's policy is surely well-intentioned, it is not likely to have the desired effect. The Bear Stearns saga highlights an important, but not always appreciated, fact about how we place value on things. Value is a quality that we assign to something based on what we think the future holds. We buy a stock not so much for what has happened in the past but for what we expect the company to do in the future. So when the market for Bear Stearns collapsed on Friday, it was a collective signal that effectively said, "Abandon hope!"

Hope is what gets us out of bed every morning. It is what impels people to toil in jobs that they would otherwise rather not do. It compels others to buy lottery tickets, and hope even makes us have children. All for the belief that things will be better in the future.

Hope, not the Fed, is the engine of the economy.

Unfortunately, the Fed's move doesn't go nearly far enough in restoring hope that the economy will improve in the near future. It smacks of desperation more than anything else.

So where does hope come from? The sources are varied, but as a neuroscientist, I believe that the final common pathway is through dopamine released in the brain. Until the early 1990s, the prevailing view of dopamine was that it was a neurotransmitter of pleasure. The research, both in monkeys and humans, has subsequently shown that dopamine is released well in advance of pleasure. In fact, dopamine seems to function primarily as a chemical of anticipation -- anticipation that something good will happen. When dopamine is released, it sets up the brain to do something, kind of like a fuel injector for action. Without dopamine, the person retreats into a state of inertia. Think Parkinson's disease.

So, the Fed's move, rather than stimulating the market, may have the opposite effect and grind it to a halt.

I hope not.