The Cortical Factor
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Every once in a while, the thinking part of our brain comes in handy. Pity we don't use it more often.
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The frontal cortex and moral decision-making. Take the teen-age brain - please!
Let's back up. According to neurobiologist Robert Sapolsky of Stanford, in a 2010 lecture to undergrads there, the frontal cortex is about doing the harder thing, if it is the right thing to do. Essentially, the more developed cortical areas modulate our more primitive limbic impulses, including learned (and virtually automatic) behaviors that are no longer stored in the frontal cortex.
This tends to involve the frontal cortex, boosted by dopamine, amping up weaker neural circuits and inhibiting stronger ones. Those with cortical damage or dementia experience major system failures. Their brains default to the stronger circuits, even if these represent the wrong thing to do in the particular situation. They fail to stay on task. They give into temptation. They fail to delay gratification in pursuit of the long-term reward.
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REM sleep offers a spectacular example of the frontal cortex going off-line. We dream all kinds of crazy stuff. We do things in our dreams we would never contemplate doing awake. Then there is the strange case of Phineas Gage.
Life Without a Frontal Cortex
In 1848, while tamping down blasting power during the construction of a railroad line, the powder exploded, sending the tamping rod through the side of Gage's skull and out the top, taking out his left eye and emptying out most of his frontal cortex. Amazingly, because the rod cauterized his blood vessels, Gage was able to get up and walk a mile-and-a-half to the nearest doctor.
Gage achieved a partial recovery, but experienced major problems controlling his behavior, leading his physician to conclude that this part of the brain "reins in our animal energies." Interestingly enough, about a quarter of those on death row have a history of concussive trauma to the head.
The Strange Phenomenon Called Teen-agers
The frontal cortex is the last part of the brain to fully develop - to fully form all the myelin on its axons, to get its full complement of synapses. The front part of the brain fully goes online for the first time at around age 25. Younger than that and we're dealing with limbic systems with feet.
Interestingly enough, says Dr Sapolsky, because the frontal cortex is the last part of the brain to develop it is the part of the brain least constrained by genes and most sculpted by environment and experience.
So - take an adult and take a teen-ager. Assign each one a task and give a greater reward than anticipated. Dopamine levels go up, driving frontal metabolism, but a lot higher in the teen-ager. Then change things around. Do not give out the reward. Dopamine levels go down, only much lower in the teen-ager. Says Sapolsky:
The gyrations are much more extreme. The dopamine-driven metabolic changes in the frontal cortex are more dramatically large for reward, are more dramatically having the floor fall out from under it for lack of reward, for disappointment. It is a system that is essentially less regulated.
Major bummer: The frontal cortex loses neurons as it ages, which explains your grandmother telling you that your new hairdo looks rotten.
Can elevated resting metabolism in the frontal cortex be too much of a good thing? Dr Sapolsky gives the example of repressive personalities, individuals who are highly regimented, highly disciplined, not depressed or anxious, who do not express emotions very readily and are very bad at reading emotions in other people. "This is the roommate who always has all the work done three weeks before the due date."
But low resting metabolism in the frontal cortex is not such a good thing, either. Think sociopath. Give a sociopath a routine brain task and they have to activate more of the frontal cortex than other people do.
Meanwhile, see how long a marshmallow on the table lasts with a four-year-old kid in the vicinity. Can the kid rein in his impulse with the promise there will be more marshmallows in 20 minutes if he leaves that one alone? In other words, how many frontal synapses do you have? Funny you should ask. The kids who held out the longest scored much higher on their SATs and other success measures years later.
Depressing fact: Already by age five there is a relationship between your socio-economic status and the thickness of your frontal cortex and its resting metabolic rate. What is that all about? This is the part of the brain that has one of the highest rates of receptors for glucocorticoids. Glucocorticoids are released in response to stress, and when too many of them are on the rampage neurons atrophy. Get born into the wrong family, be raised with the stress of poverty and already by age five the size and activity of the brain has taken a major hit.
Says Sapolsky: "That is one of those factoids that should have people rioting at the barricades."
Hold that thought ...
Enter the Amygdala
Lower mammals have an olfactory hotline to the amygdala, the part of the brain in the limbic system that mediates fear and arousal and kickstarts fight or flight. Furry creatures are literally primed to react when they smell something funny. Mammalian limbic systems are standard issue for humans, except ours are wired to respond mainly to visual stimuli.
Ordinarily, the cortical areas of the brain are responsible for visual processing and sending info to the amygdala, but we don't always have time to wait. There is a short-cut in the brain through the lateral geniculate (LG). The trade-off is that this information is less accurate. We're more likely to make mistakes. There is strong evidence that this pathway is hyper-excitable in those with PTSD.
The amygdala and the frontal cortex essentially regulate each other. The projections from the frontal cortex are inhibitory, as are the projections from the amygdala. In Sapolsky's words: "The frontal cortex is trying to get the amygdala to restrain itself. The amygdala is trying to get the frontal cortex to stop sermonizing at it."
When the amygdala succeeds, "that's the world in which you are making astonishingly bad decisions. ... That's the world of the amygdala getting very inaccurate rapid-fire information." Out comes behavior that is seriously unregulated.
Meanwhile, Over in the Anterior Cingulate
The anterior cingulate (ACC) is part of the cingular cortex snaking beneath the outer cortices. This is a region of the brain implicated in empathy. Typically, in hypothetical exercises involving agonizing moral choices (such as do you strangle a crying baby to save the lives of a group of people hiding out from the Nazis?), those who make the cold-blooded utilitarian decision are shown to have the least activation in the ACC.
The Metaphorical Brain
We are called upon to make judgments concerning abstract moral concepts. The problem is our brains did not evolve for doing symbols and metaphors. We are stuck with the old circuitry. Thus, a test subject handed a warm drink in an elevator by a stranger will rate that individual as warm. Cold for a cold cup.
Wait, it gets even more weird. Registering moral disgust? The insular cortex activates. This is the part of the brain that processes foul stimuli such as rotting fish. Contemplate the etymology of the word, disgust. Further contemplate that every language on earth employs similar terms for the same phenomenon. Says Dr Sapolsky:
When humans came up with something as fancy as moral transgression, where are you going to stick the sense of outrage you feel? I know - let's hijack the part of the brain that tells you you're eating rotten food.
Recall Sapolsky's sense of outrage over what the stress of poverty does to the brains of kids. Compare that to this statement by Mitt Romney during the 2012 Presidential primary season: "I'm not concerned about the very poor." (And no, this is not out of context.)
Could it be that Mitt is one of those low-activating anterior cingulate types? Dr Sapolsky does not mention Republicans, but that shouldn't stop us from making our own connections. Says Sapolsky, citing Nobel Laureate Eli Wiesel: "The opposite of love is not hate. The opposite of love is indifference."
Dr Sapolsky points out that love and hate are physiologically very similar. From a strictly biological perspective (such as brain activation, heart rate, and so on) it is very difficult to tell the two apart. Indifference is the real evil, which is another good reason to register our disgust.
But hold on. We also have a whole class of liberal-haters who define themselves as being disgusted with the disgusted. Recall this from yet another Presidential candidate, Newt Gingrich, in reference to Occupy Wall Street: "Go get a job, right after you take a bath."
Ah, another stinking political opportunist (using a bath metaphor at that) who makes liberals want to throw up. Confused? So, apparently, is everyone. Dr Sapolsky cites the work of John Haidt of the University of Virginia in support of the proposition that affective response drives moral decision-making rather than the other way around.
Say, for instance, a brother and a post-reproductive sister want to have a sexual relationship. Is it okay for them to have one in private? How about burning a flag and stomping on it? Or cutting up your dead pet and eating it?
I don't know about you, but I definitely registered a high-level gut reaction to that last proposition. Fine, but can I come up with a rational answer in response to the question: "What's wrong with that?"
This is essentially the same question Dr Haidt asked his test subjects. They, too, had trouble framing rational responses. Basically, on an emotional level, something doesn't "feel right." The frontal cortex is spinning its wheels, the gut makes the call. Eventually, the thinking parts of the brain lock in, but too often in a rationalizing display of post hoc rubber-stamping.
As Sapolsky explains: "We are dealing with a very ancient brain, one that is not very good yet at separating the limbic world from the cortical one."
Maybe that's why we need a judiciary to protect ourselves from our own inept decision-making. In early Feb 2012, a federal appeals court struck down California's infamous Proposition 8, a voter referendum passed in 2008 that would have banned gay marriages in the state.
Is there anything wrong with disgust? Even right-wing disgust? Of course not. Of all things, disgust is morally neutral. From a neurobiology perspective, it is basically a rotten fish reaction. We need our rotten fish reactions. They drove the civil rights movement, which is why we need to be suspicious of low-activation anterior cingulate guys who lack the kind of empathy that makes us capable of moral outrage in the first place.
The problem is we often fail to couple thinking to our disgust. "What's wrong with that?" It's a question we need to be asking - over and over and over.
This piece is based on Lecture #18 of a 25-part video lecture series by leading neurobiologist Robert Sapolsky. Dr Sapolsky features in other articles on this site, including Stress, Anxiety, and The Biology of Human Behavior.
Further reading: Thinking With Our Emotions
Based on three blogs published in early Feb 2012, reworked as an article Feb 9, 2012
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