Judging the Seven Deadly Sins

Consonant with the Fundamental Attribution Error, people tend to believe that other people’s actions are manifestations of their moral character. If someone drives past us on the highway at a rapid rate of speed, we tend to quickly conclude that the driver is a reckless jerk. Of course, we are good people and when we speed past other cars, it’s because we are late to an important meeting or to pick up our kids after school.

In his recent book Seven Deadly Sins: The Biology of Being Human (2024), neurologist Guy Leschziner reminds us that we should keep the Fundamental Attribution Error in mind when judging others’ actions because people often commit one or more of the seven deadly sins—just in case you don’t remember them: wrath, gluttony, lust, envy, sloth, greed, and pride—because of causes that have nothing to do with their moral character. Says Leschziner: “For all of us, these ‘sinful’ character traits are perhaps less of a moral issue and more of a biological one, raising questions of responsibility, blame and free will in the face of sin.” (p. 8)

Consider wrath, which becomes particularly problematic when it manifests as aggression. Leschziner examines case studies of his patients and others who have become aggressive primarily because

they suffer from epilepsy which can (rarely) carry this side effect
their doctors have prescribed drugs that cause them to react aggressively
their unique brain chemistry amplifies to an unusual degree the normal emotion of anger
they sustain traumatic brain injury (TBI) as did the famous Phineas Gage who survived when a long iron pole passed entirely through his skull in a railroad construction accident, but became uncharacteristically belligerent, angry, and aggressive afterward
they suffer, due to an interplay between genetic and environmental factors, a personality disorder, such as psychopathy, which is found in up to 25% of men and 17% of women in prisons, though in only 1% of adults in the general population.

Or think about gluttony, which we most commonly associate with people who are overweight and often judged by others as lacking the willpower to resist overeating. Leschziner has a fascinating section on Prader-Willis syndrome (PWS), a genetic malfunction that causes a victim’s brain to think that it is always hungry. Studies indicate that at least 97 genes are associated with body mass index and 40-70% of obesity is explained by common genetic variants, though environmental factors (such as having an obese friend) can also contribute, as can various viruses and gut microbes. Concludes Leschziner: “the truth is that ‘gluttony’ is not a moral act, a failure of our ‘souls’. Our appetite is a consequence of our genes, our guts and those functions in our brains that control our hunger and mediate the reward of food.” (p. 110)

Lust would seem to be a “sin” with a strong tie to moral failings, and it often is. But Leschziner has seen patients and studied others who, after TBIs, tumors, or strokes, all of a sudden could not stop talking about sex, became sexually attracted to children, started exposing themselves in public, demanded unreasonable amounts of sex from their partners, and so on. Up to 35% of people arrested for exhibitionism have brain disorders that appear to contribute to this activity, and 14% of pedophiles suffer from neurological damage. Says Leschziner: “Our drive for sex is a biological imperative. Its outward manifestations are simply a result of the machinations of those areas of our brains that drive it and hold it back. It is when it is amplified or unrestricted, though brain injury, medications or our environment, that it ruins lives.” (p. 160).

Envy and the separate but related notion of jealousy are very normal human emotions that only cause trouble and might be viewed as moral failings when carried to extremes. When they are, it is often because the person has a personality disorder such as NPD (narcissistic personality disorder). Approximately 10% of us suffer personality disorders, says Leschziner, which:

…are thought to result from interactions between an underlying neurobiological predisposition—in part genetic—and stresses during development [such as childhood trauma]. … [I]ncreasingly it is recognized that there are strong biological factors at play. Personality is strongly influenced by hereditary factors, and twin studies comparing identical and non-identical twins suggest that genes have a potent role in the development of personality disorders too. Research in personality disorders also suggests differences in neurotransmitter systems, volumes of certain brain structures important in the regulation of emotions and disruptions in networks that are involved in behavior. (p. 169)

Again, so much more is going on here other than just poor moral choices by an envious or jealous individual.

You get the idea. Leschziner goes through the final three deadly sins (sloth, greed, and pride), again finding many environmental, genetic, brain-related and other causes that often contribute to people committing these seeming moral wrongs.

All this raises several obvious questions, perhaps best addressed by philosophers and policy makers, including how to best handle people who have broken widely-accepted moral codes, but done so, in part, because of these genetic, biological, environmental and other factors.

In his final chapter, Leschziner addresses the long-standing debate as to whether there truly is such a thing as human free will. He leans toward a “no” answer to the question but, at the same time, is unable to conclude that as a society we should simply say to a Hitler or to a seemingly monstrous murderer he profiles in detail who was repeatedly and horrifically abused as a child: “Not your fault. It’s your brain. You shouldn’t be punished, or at least not as much as someone who did the same deeds without the tumor, the TBI, or the stroke.” Near the end of his book, Leschziner writes:

As I write these words, I admit to being somewhat surprised at myself. I consider myself a progressive in many ways, but have always taken a slightly more reactionary approach to crime and punishment, to morality and guilt. However, there are strands of neuroscience that have reached the same destination as many philosophers like Galen Strawson and Derk Pereboom, albeit from a different perspective: if indeed there is an absence of free will, criminal justice is (or should be) a mechanism for the protection of society and rehabilitation, rather than a meter of morality. (p. 314)

Words worth pondering.