"We have a moral imperative to acknowledge the reality of IQ. Low IQ is a risk factor for all causes of death, shows substantial genetic influence, and makes living in a complex society impenetrable. To assume those with low IQ just lack motivation is cruel"
The Dangers of Ignoring Cognitive Inequality
by Wael Taji
On Sunday 28 April 1996, Martin Bryant was awoken by his alarm at 6am. He said goodbye to his girlfriend as she left the house, ate some breakfast, and set the burglar alarm before leaving his Hobart residence, as usual. He stopped briefly to purchase a coffee in the small town of Forcett, where he asked the cashier to “boil the kettle less time.” He then drove to the nearby town of Port Arthur, originally a colonial-era convict settlement populated only by a few hundred people. It was here that Bryant would go on to use the two rifles and a shotgun stashed inside a sports bag on the passenger seat of his car to perpetrate the worst massacre in modern Australian history. By the time it was over, 35 people were dead and a further 23 were left wounded.
Astoundingly, Bryant was caught alive. He was arrested fleeing a fire at the house into which he had barricaded himself during a shootout with the police. He later pled guilty to a list of charges described as “unprecedented” by the standing judge, and was sentenced to life in prison without the possibility of parole, thus sparing his victims and other survivors the suffering (and perhaps the catharsis) of a protracted trial. Yet, in spite of his guilty plea, Bryant did not take the opportunity provided by his official statement to offer any motive for his atrocities. Instead, he joked “I’m sure you’ll find the person who caused all this,” before mouthing the word ‘me.’ Intense media speculation followed, the main focus of which was Bryant’s history of behavioral difficulties. These were offered as possible evidence of a psychiatric disorder such as schizophrenia (which would have been far from sufficient to serve as a causal explanation for his crimes). However, the most notable and concrete fact of Bryant’s psychological condition was his extremely low IQ of 66—well within the range for mental disability.
IQ scores are classified in a number of ways, all of which are broadly similar. The Wechsler Adult Intelligence Scale (WAIS-IV) establishes seven categories of IQ scores. Most of us fall into the ‘Average’ band, constituted by the 90-109 range. Those achieving scores of 130 or higher are considered ‘Very Superior.’ Conversely, scores of 69 and under are classified as ‘Extremely Low,’ and automatically qualify the scorer for a diagnosis of ‘mild retardation’ according to the APA’s Diagnostic and Statistical Manual of Mental Disorders. It is into this band that Bryant’s score falls.
The connection between intelligence and behavioral problems, such as Conduct Disorder (CD) or Antisocial Personality Disorder (APD), was well-known around the time of the Port Arthur Massacre. A review by biostatistician and UCSD professor Sonia Jain cites contemporaneous studies to suggest that low IQ scores in childhood should be considered a risk factor for APD and CD. In 2010, several psychologists published results from a longitudinal study containing data on over a million Swedish men, who were tracked from conscription for a little over 20 years. They found that IQ scores tested during conscription were a significant and robust predictor, not only for APD or CD, but for all categories of mental disorders. Conscripts with low IQ were substantially more likely to be diagnosed with one or more mental disorders, to suffer from mood and personality disorders, and to be hospitalized for mental illness. Those in the lowest band—like Bryant—were most at risk of severe psychological disorders.
While these correlations are concerning, they do not offer an explanation for Bryant’s atrocities. In a population where intelligence is normally distributed with a mean of 100, a little over two percent of people would attain IQ scores close to Bryant. A further 15 percent would receive IQ scores somewhere below 84—well beyond the threshold for disqualification in the Armed Forces Qualification Test (AFQT), used to determine suitability for admission into the US Army until 1980. Careers for those below this level are extremely rare—a fact that might help explain the correlation between low IQ and an enhanced risk of criminal offending, given the scarcity of well-paid jobs for those with an IQ of below 84.
But much of this correlation is due to street-level petty and violent offenses, not mass murder, and it would be abhorrent—obscene, even—to suggest that people with a low IQ should be treated with suspicion, or as murderers-in-waiting. In almost all cases, these individuals pose a risk to no one but themselves, and are more likely to fall prey to victimization by others. On the other hand, it is equally irresponsible to ignore the specific difficulties which those with a low IQ face. The consequences of this wishful thinking—however noble in intent—can be devastating.
Perhaps the best example is offered by the recent history of the Cold War. While the American military-industrial complex was sufficiently sophisticated to provide the United States with all the arms and armaments it could possibly hope for, there are always things that money cannot buy. In this case, it was bodies—young American men needed to fight on the ground in 1960s-era Vietnam, where they found the most unforgiving of battlefields among the region’s unassuming jungles and innocuous rice paddies. The unusually high attrition rate of soldiers posted there, as well as the frequent use of student deferments or feigned illness to dodge the draft (President Trump’s excuse of ‘temporary bone spurs’ constitutes one particularly famous example), resulted in a shortage of men which meant that more troops were needed than the nation was able to supply.
The government was confounded by this problem for some time, attempting halfhearted crackdowns on draft dodgers as a temporary solution, until Secretary of Defense Robert McNamara arrived at a more permanent workaround. The US government would draft men whose low IQ scores had hitherto disqualified them from military service. This stratagem—codenamed ‘Project 100,000’—is detailed along with its dreadful consequences in the book McNamara’s Folly by the late Hamilton Gregory. Gregory witnessed the fate of the low-IQ draftees firsthand while he was a soldier in Vietnam. These draftees—cruelly nicknamed ‘McNamara’s Morons’—were generally capable of completing simple tasks, but even a simple task imperfectly executed can be disastrous in warfare.
A case study in the book is ‘Jerry’ (not his real name). Jerry was a draftee from the 100,000 who had been assigned guard duty in a camp by the Quan Loi Green Line. Jerry’s task was to challenge anyone approaching the camp by calling: “Halt! Who goes there?” followed by “Advance and be recognized!” once a response had been obtained. This task was minimally demanding due to the clearly visible differences between an American soldier and the average Vietcong guerrilla. But when a well-liked American officer returned to camp, Jerry bungled his instructions. Upon seeing the officer approaching, he yelled “Halt!” and then opened fire, killing the man where he stood. Jerry subsequently disappeared in what was either an act of remorseful abscondence or murder by outraged members of his battalion. In another case described by Gregory, one of the ‘morons’ played a joke on his squadmates by throwing a disarmed hand grenade at them. Despite being beaten up for it, he found this prank so amusing that he repeated it every day until the inevitable happened; he forgot to disarm the grenade, causing the deaths of two soldiers and the grievous wounding of several more.
What happened to many of the 100,000 (whose actual total exceeded 350,000) is not hard to predict. “To survive in combat you had to be smart,” Gregory writes. “You had to know how to use your rifle effectively and keep it clean and operable, how to navigate through jungles and rice paddies without alerting the enemy, and how to communicate and cooperate with other members of your team.” Fulfilling all or any one of these minimum requirements for survival in a battlefield is contingent upon a certain level of verbal and visuospatial intelligence, which many of McNamara’s draftees did not possess. This ultimately led to their fatality rate in Vietnam exceeding that of other GIs by a factor of three.
The danger of physical harm faced by those with a low IQ is not restricted to the battlefield. A 2016 study by four psychologists using data from the Danish Conscription Database (containing 728,160 men) revealed low IQ to be a risk factor for almost all causes of death. A drop in IQ by a single standard deviation (roughly 15 points) was associated with a 28 percent increase in mortality risk. The association between low IQ and mortality was particularly great for homicide and respiratory disease (such as lung cancer). The high homicide rate could reflect a predisposition for those of low IQ to find themselves in dangerous situations, perhaps due to a lack of economic opportunity or an increased likelihood of being victimized by predatory individuals. Similar features could explain the prevalence of respiratory disease, which may be a product of high rates of smoking as well as a greater likelihood of inhabiting more polluted industrial areas where it’s easier to find low-skilled work. Clearly, being born with a low IQ is sufficient to set one up for an unlucky and unhappy life. But could low IQ have contributed to—not explain, but be a factor in—the massacre committed by Martin Bryant?
To answer this question, we have to transcend mere correlations between IQ and different types of outcome, and consider that those with low IQ are much more likely to experience misfortune in seemingly every endeavor. Having intelligence is what allows us to operate in the world—both on our own, and within the societies we inhabit. Those lucky enough to have a high IQ have an easier time at dispatching the various challenges they face, and thus naturally rise within hierarchies of competence. We can imagine any number of these hierarchies, most of which are unimportant (the hierarchy of Rubik’s Cube solvency speed, for example, is probably irrelevant), but all of which require some degree of intelligence. Furthermore, some of these areas of success—such as friendship groups, romantic relationships, and professional employment—are so fundamental to the individual pursuit of happiness that to be unable to progress in them is profoundly damaging to one’s sense of well-being and intrinsic self-worth.
This means that having a low IQ doesn’t only make you more likely to get killed or fall victim to an accident. It also means you’re more likely to undergo difficulties in progressing up every ladder in life. You’ll often feel permanently ‘stuck at zero’—unable to improve or change your position. Most of us will experience this feeling at least a few times in our lives, whether encountered in school (being unable to break the ‘A-grade’), in our social lives (being unable to establish or maintain a successful romantic relationship), or in comparatively trivial areas. Yet most of the time, it is transient—passing when we switch our efforts to a new endeavor, or after devising a way to solve the problem. Very few of us know what it is like to have that feeling almost all of the time—to have a large proportion of one’s attempts at self-betterment or advancement frustrated by forces that seem to be beyond our control. Being trapped in such a dismal psychological state for only a brief interval can lead to anxiety, depression, or dependence. In some, this feeling of ‘being stuck at zero’ (that the world is manifestly unfair and against them) will lead to resentment—and resentment can turn into murderousness.