Declining IQ: A Race to the Bottom?

Over the past several decades, American children’s physical and mental well-being has steadily deteriorated. Over half (54%) of all U.S. children (as of 2007) had a chronic health condition—with developmental and behavioral problems, obesity, allergies, asthma and mental health conditions leading the pack—and the prevalence of many of these conditions doubled from 1988 to the mid-2000s. Federal reporting on pediatric health indicators in 2017 showed that one in five children (kindergarteners through adolescents) were obese, one in ten had activity limitations resulting from chronic health problems, and one in seventeen (more males than females) had, according to a parent, “serious difficulties with emotions, concentration, behavior or getting along with other people.” In addition, 12% of adolescents suffered a major depressive episode in the previous year, with the prevalence of teenage depression rising continuously since 2004 and suicide representing the second leading cause of death for both teens and young adults.

A converging body of evidence calls attention to a consistent decline in basic cognitive abilities and ‘mental speed,’ particularly in young males, beginning in the mid-to-late 1990s.

Mild and serious developmental disabilities are one of the most prominent faces of the health crisis affecting American children (and, increasingly, children in other countries as well). These disabilities have obvious and sobering implications for individual children’s learning trajectories and future cognitive achievements—but also for society as a whole. In the U.S., plummeting SAT scores are one proxy indicator of the cognitive fallout; the scores have been falling for over a decade and are at historically low levels, reflecting an across-the-board worsening in critical reading, math and writing performance. A news report in 2013 suggested that almost three-fifths (57%) of graduating high school seniors were not ready for college.

In Europe, researchers have been systematically assembling other types of cognitive data to examine intelligence quotient (IQ) trends over time. A converging body of evidence calls attention to a consistent decline in basic cognitive abilities and “mental speed,” particularly in young males, beginning in the mid-to-late 1990s. An article in the British popular press noted the falling IQ scores in 2014 and pointedly asked, “Are we becoming more STUPID?” Ignoring the belligerent tone of the journalist’s question, it seems logical to follow up with another question: what is causing the decline in measured intelligence? A new study that reports “large changes in average cohort intelligence” in recent years has the answer—the turnaround in IQ is due to environmental factors.

A new study that reports ‘large changes in average cohort intelligence’ in recent years has the answer—the turnaround in IQ is due to environmental factors.