Evil Genes

by Barbara Oakley

  A number of other genes also affect mood, although our understanding of how is limited at present. Tryptophan hydroxylase (TPH), for example, is an enzyme that helps in synthesizing serotonin. Various types of TPH and their associated genes appear to be associated with a number of different psychiatric and behavioral disorders—including those, as we shall see, which relate to Machiavellian behavior.45 Another gene—this one with the cryptic handle of D4DR—has been linked to novelty seeking. D4DR has a variable number of repeats in its nucleotide building blocks that can affect how quickly dopamine is metabolized by the body. The higher the number of repeats, the more novelty-seeking behavior a person seems to exhibit—and the more extroverted a person often is. Shorter forms may be associated with crankier personalities.46

  And another recent discovery, the DARPP-32 gene, has been found to be associated with both optimized thinking circuitry and, sadly, increased risk of schizophrenia. Daniel Weinberger explains: “Our results raise the question of whether a gene variant favored by evolution, that would normally confer advantage, may translate into a disadvantage if the prefrontal cortex is impaired…. Normally, enhanced cortex connectivity with the striatum would provide increased flexibility, working memory capacity and executive control. But if other genes and environmental events conspire to render the cortex incapable of handling such information, it could backfire—resulting in the neural equivalent of a superhighway to a dead-end.”47 It turns out that DARPP-32 is associated with depression and substance abuse as well as with schizophrenia.

  Still more genes relate to the hormones vasopressin and oxytocin and help produce the feelings of love we may feel for others.c.48 Perhaps, when set on “high,” these genes help produce the kind of person who continually, gullibly forgives all manner of purposeful emotional and physical abuse.

  In the end, all of the genes mentioned above, and many others as yet unknown, could prove important in any number of personality traits. It will be interesting to watch developments as the field of behavioral genetics unfolds.

  EMERGENIC PHENOMENA

  A particularly significant concept that we must not ignore here is something called emergenesis. This term refers to genetic traits that, surprisingly, don't commonly run in families. Examples of this might include leadership, many different types of genius, and psychopathological syndromes like psychopathy and borderline personality disorder.49 The way this occurs isn't all that difficult to understand. Let's say, for example, that a brilliant executive, known for his extraordinary leadership skills and visionary sense of business, along with his petite wife, who had won a gold medal in the Olympics as a teenage gymnast, has a large family of ten children. What might we expect?

  The children would each receive half their genes from their mother, and half from their father, although there's no telling beforehand what scrambled mixture they might receive. Let's say that part of the father's business acumen and leadership skills relate to an outstanding memory provided by a val/val BDNF set of alleles, coupled with a calming long/long serotonin transporter (SERT) allele set. (Of course, there are many other genes that play a role here, but we're simplifying this just to make the point.) The executive's fortunate confluence of BDNF and SERT alleles are part of why he thinks fast and can remain unflustered no matter what might arise. The gymnast wife, on the other hand, may have a short/short serotonin transporter molecule, making her routinely more anxious, but her met/met BDNF alleles mean she's still fairly easygoing, although they also ensure her memory is nowhere near as sharp as that of her husband.

  With this setup, none of the ten children would have any real chance at all of having precisely the same four genes as either of their parents. Just the slight difference in these genes might be enough to take the edge off of each child's ability to replicate either of the parents’ successes (or, if the scenario were changed—their failures). And that's for those four genes alone. Multiply this by the as yet unknown number of total genes that have substantive effects on any particular personality trait—two hundred? Two thousand? And remember, there's also that, as yet barely understood, control information hidden in the junk DNA. You couldn't possibly have a chance at replicating precisely the same personality-related genome that the parent has into a child—although you could definitely inherit a confluence of genes that would allow you to show some key factors, including impulsivity, anxiety, intelligence, or extraversion. Put differently, if your father were a Leonardo da Vinci–caliber genius, chances are you'd be pretty smart but no genius yourself.

  Inheritance of personality is particularly touchy because other, seemingly nonpersonality-related genes also factor into the equation. Even if a child is given nearly the identical personality underpinnings as the parent, her entire life might be different, for example, if she also happened to inherit a difficult-to-battle tendency toward obesity. Or perhaps she might have inherited genes that gave her a particular delight in music or skill at dancing, or predisposed her toward preternatural enjoyment of the buzz of alcohol, or gave her a low ability to maintain focus even on things that interest her.50 And of course environment can play a role too. Even within the same family, she might have been treated very differently than her older sister was. Or maybe her mother played with a cat and was infected with toxoplasma gondii before she even knew she was pregnant, setting up the conditions for her daughter to become schizophrenic.51 Or perhaps she was kidnapped and brutally raped as a nine-year-old and dumped bloody and bruised by the side of the road.

  All of these reasons, both genetic and environmental, are why virtually all parents with more than one child are amazed at how their children could be so very different. (“Night and day” is the common refrain.) Only identical twins could be expected to have nearly precisely the same genotype—and even that genotype, of course, will be quite different from that of the parents.

  WHY WE CAN'T SIMPLY ELIMINATE “EVIL” GENES

  Some studies have shown that if one of your first-degree relatives has the emotionally unstable condition known as borderline personality disorder, you've got an 11 percent possibility of having the disorder yourself—a substantial increase over the 1 to 2 percent chance for the disorder in the general population, but far from absolute certainty.d.52 The concept of emergenesis explains this spotty evidence for heritability. Having full-blown borderline personality disorder probably requires inheriting just the right confluence of genes related to very different traits involving cognitive dysfunction, mood disorder, and impulsivity, and often needs a final spark from a stressful environment to set things afire. Indeed, studies have shown that the borderline traits of affective instability and impulsivity run in families.54 But since each of the unlucky borderline traits involving impulsivity, mood disturbances, and cognitive dysfunction is, for the most part, separately heritable, it's unlikely that you'd inherit every one of them, even if one of your parents were to be borderline. We have reason to believe that the spotty heritability situation is similar with antisocial personality disorder (which can actually arise from many different causes, some of which are solely environmental), and even psychopathy.

  An Emergenic Prodigy Speaks of Jewish “Smarts”

  Norbert Wiener was a child prodigy who received his doctorate from Harvard at age eighteen; he would go on to discover important mathematical properties related to communications, robotics, computer control, and automation. Wiener's father claimed that it was his training methods alone that had made his son so brilliant—otherwise Norbert would have been a perfectly ordinary child. Given the fact that the three other children in the family were not especially gifted, Norbert, with his emergenic genius, found his father's statements extraordinarily galling.53 In tandem with his intellectual brilliance, Norbert was hypersensitive to criticism and subject to fits of depression.

  Due to fear of anti-Semitism, Wiener's Jewish heritage was kept a secret from him as a child—afterward he became interested in Jewish culture and heritage. (Actually, Wiener was fascinated by virtually everything
.) Anticipating research findings that would come a half century later, Wiener wrote:

  Let me insert here a word or two about the Jewish family structure which is not irrelevant to the Jewish tradition of learning. At all times, the young learned man, and especially the rabbi, whether or not he had an ounce of practical judgment [shades of the COMT intellect-emotion trade-off] and was able to make a good career for himself in life, was always a match for the daughter of the rich merchant. Biologically this led to a situation in sharp contrast to that of the Christians of earlier times. The Western Christian learned man was absorbed in the church, and whether he had children or not, he was certainly not supposed to have them, and actually tended to be less fertile than the community around him. On the other hand, the Jewish scholar was very often in a position to have a large family. Thus the biological habits of the Christians tended to breed out of the race whatever hereditary qualities make for learning, whereas the biological habits of the Jew tended to breed these qualities in. To what extent this genetic difference supplemented the cultural trend for learning among the Jews is difficult to say. But there is no reason to believe that the genetic factor was negligible.55

  Wiener had no way of coming up with a more concrete, testable model for his speculations. But in 2005, scientist Gregory Cochran, working independently of any institution, along with Jason Hardy and Henry Harpending of the University of Utah, finally proposed just such a model. Cochran and his colleagues suggested that a group of European Jews known as the Ashkenazi commonly carried several genetic mutations that explained their naturally high intelligence. (Ashkenazim score about twelve to fifteen points above the average of one hundred on IQ tests—the highest of any group of humans.) A single dose of the novel alleles can increase the growth and number of connections between nerve cells. As with many seemingly beneficial genes, there are trade-offs. Those with a double dose of the allelles can wind up with neurological disorders such as Tay-Sachs disease, as well as with cancer.56 Of course, the above findings are highly controversial.

  But just what is the difference between, say, the mind of a psychopath and that of a normal person? We are at the cusp of cutting-edge technology that allows us to see. And seeing the differences between psychopathic and normal neurological processes is a crucial step in allowing us to begin to understand the underpinnings of some types of Machiavellian behavior. As we shall discover, understanding the “why” of Machiavellian behavior will also help us to understand why there are Machiavellians at all—and why some of them are so successful.

  * * *

  a.Since Plomin's comments, a twin study has shown that a tendency toward being religious does indeed appear to be moderately heritable. Such a tendency, it seems, is strongly influenced by the environment during adolescence. However, by adulthood, religiousness seems to slip away somewhat unless you've got genes that predispose you toward religion.

  b.Okay, if you really wanted to be picky here, you could say “problematic alleles,” or even “quantitative trait loci that have been affiliated with specific personality disorders,” with the caveat that environment can often play an important accompanying role in those with a genome that has set them at risk. But it doesn't have quite the same ring, does it? In any case, it's important to remember that depending on the constellation of other genes in a body, supposedly evil genes might have a neutral, or even positive effect. Or such genes could have mixed positive and negative effects, such as increased intelligence coupled with increased neuroticism.

  c.Indeed, since the first edition of Evil Genes, a study by researchers at the Hebrew University in Jerusalem has demonstrated a tentative link between ruthless behavior and variations in a gene that produces vasopressin receptors. For this study, roughly two hundred students had their DNA sampled and were then asked to play a game that (unbeknownst to the students) was called the Dictator Game. Students with shorter versions of the vasopressin receptor gene (AVPR1a) were more likely to behave selfishly.

  d.Twin studies show that if one identical twin has full-blown borderline personality disorder, there is a 35% chance the other has it, while fraternal twins have only an 8% chance of sharing the disorder. Subclinical borderline personality disorder, on the other hand, showed a concordance of 38% for identical and 11% for fraternal twins.

  “In the beginning, there was nothing. And God said, ‘Let there be Light.’ And there was still nothing. But you could see it.”

  —Anonymous

  LOOKING INSIDE THE BRAIN OF A PSYCHOPATH

  “Parents of violent kids think, ‘What did I do wrong?’” says Adrian Raine, a “Penn Integrates Knowledge” professor who holds joint appointments in criminology and psychiatry at the University of Pennsylvania. “When the kids come from a good home, the answer may be absolutely nothing. A biological deficit may be to blame.”1

  And now we are beginning to be able to “see” the deficit.

  One of the most powerful methods of seeing inside the brain involves magnetic resonance imaging—often shortened to MRI. In this technique, water molecules are tickled to cause them to burp out electromagnetic waves that are only slightly different in frequency from the electromagnetic waves our eyes see as light. Since different types of tissue have different amounts of water, we can use clever technical legerdemain to “see” the different tissue types on photographs that look very similar to x-ray images.

  A complete slice of the brain can be seen—“imaged”—in the same way that you are scanning your eyes across this page. Since an image can be produced very quickly (only twenty milliseconds—about one-fifth of the time it takes to blink your eye), it is possible to produce a number of MRI pictures one right after another as if filming a movie. In this fashion, as cells and molecules carry out the work of the brain, the differences between images can clearly be seen. This video version of MRI is called functional MRI, or fMRI. MRI compares to fMRI in the same way a picture of you posed with a cheesy smile in your sixth-grade class picture compares to an old home movie of you throwing a snit. You can see what you looked like from the still picture, but you can tell a lot more about how you functioned from the home movie.2

  EMOTION AND LANGUAGE

  The following illustrations, from an fMRI study by Yale psychologist and neuroscientist Kent Kiehl and his group, reveal that many regions of the brain in emotionally excited psychopaths function differently than in normal people. The upper two figures of the “generic brain” show areas, highlighted in white, where criminal psychopaths had much less activity than normal subjects when repeating emotionally charged words like blood, sewer, hell, and rape.3 These neural areas relate to limbic and paralimbic levels—very old parts of the brain in evolutionary terms that are also found in fishes and reptiles. The bottom two figures, on the other hand, show areas of the generic brain where criminal psychopaths had greater activity (also highlighted in white) related to emotion than normal subjects. This increased activity may be caused by the weak input from the limbic system, which forces psychopaths to use alternative neural structures to grapple with emotional information.4

  Fig. 4.1. Four different views of a psychopath's brain. The white spots are the areas of interest.

  Finding neural differences between psychopaths and normal people looks as simple as snapping a picture with a fancy camera—and in some sense, despite the acrobatics involved in processing the data, it is simple. But occasionally it's nice to step back and admire the intricate logistics behind these types of experiments. For the images we just saw, simply being able to get the psychopaths to where they could be imaged was no easy matter. The eight psychopaths involved in the study were hauled under heavy guard fifty miles from the maximum-security prison in Abbotsford, British Columbia, to the University of British Columbia Hospital's magnetic resonance imaging unit. As Kiehl wryly understates: “The work is never boring.”5

  LOW RESPONSE TO THREATENING STIMULI AND EMPATHY IMPAIRMENT

  Another study has shown that a psychopath is likely to have a weird corpu
s callosum—the nerve superhighway orchestrating the flow of information between the brain's two hemispheres.6 The white matter volume of the corpus callosum of psychopaths is nearly a quarter larger than normal, but, like pulled taffy, the highway's length is increased while its thickness is decreased. These differences in neural structure seem to go hand in hand with the curious gaps in emotion and creepy interpersonal skills of psychopaths, along with their low involuntary reactions to stress. Why might the corpus callosum abnormalities cause these personality differences? It might be because a poorly structured corpus callosum inhibits communication between the two halves of the brain—in particular, it doesn't do its normal job of allowing the left brain to inhibit and control the negative moods that can be generated by the right hemisphere. This may cause the expression of the aggressive, unregulated behavior that psychopaths can display.7

  Researchers feel that corpus callosum abnormalities may be caused by a problem in the development of a psychopath's brain. Pruning—a natural, internal process of tidying up the brain by shearing off unused neurons—may not take place properly. Or the neurons may be too heavily encased in sheaths of myelin—insulating trestles of glial white matter.

  Fig. 4.2. This cross section demonstrates some of the brain's internal structures. The amygdala and hippocampus are actually located deep within the brain but are shown as an overlay in the approximate areas that they are located.

  LACK OF ANXIETY

  The amygdala is actually an almond-sized pair of organs deep in the brain that cause a knee-jerk “fight-or-flight” reaction when people are startled. In some circumstances, psychopaths have lazier amygdala than normal people, as was discovered when a group of psychopaths was exposed to the smell of rotten yeast (stinky smells as a rule cause the amygdala to jerk to attention). Researchers think that routinely blasé amygdalae and other related structures in psychopaths may leave them feeling restless, spurring them to raise hell just for the resulting excitement. The psychopaths’ nonchalant neural reactions may also be related to their strange lack of fear—which also appears to have a genetic basis.8 Lack of fear may in turn throttle the development of a psychopath's conscience. Some researchers feel that amygdala dysfunction lies at the very core of psychopathy.9