Life is complex, and complexity operates like a headwind that impedes progress more strongly for individuals lower on the IQ continuum. Everyone makes cognitive mistakes, but lower intelligence increases the risk of error.
Take, for example, health care. Patients differ enormously in intelligence level, and these differences have life and death consequences for them. Individuals of lower health literacy, or IQ, are less likely to seek preventive care even when it is free, use curative care effectively when they get it, understand and adhere to treatment regimens, or avoid health-damaging behavior. They have worse health, more accidental injuries, higher health costs, and die sooner—regardless of income, insurance coverage, or quality of health care. Health care matters, as do material resources and motivation, but mental resources matter too. They are critical in the prevention and self-management of chronic illnesses such as diabetes and heart disease. Health self-care is an increasingly complex life-long job for all of us, which becomes even more complex as we age and experience more health problems.
It overstates only slightly to say that health care providers currently pay no attention to patient differences in the ability to learn and understand. As health literacy researchers have shown, however, a sizeable fraction of patients in urban hospital outpatient clinics are unable to understand an appointment slip (when to come back), a label indicating how to take four pills a day, or, among their insulin-dependent diabetic patients, the signs of low (or high) sugar and what action to take to bring their blood sugar back under control. Do proportionately more blacks have such problems? Yes, many more. Is that a reason to continue ignoring or disputing individual and group differences in g?
