Did you know that exposure to lead as a child can have long-lasting effects on your intelligence, mental health, and even your personality? A groundbreaking study has revealed that childhood lead exposure not only reduces intelligence and harms mental health in adulthood, but it also alters personality traits. This discovery is particularly significant considering the widespread low-level lead poisoning that has affected an entire generation.
Lead is a dangerous neurotoxin that can have detrimental effects at any level of exposure. Extensive evidence shows that it can lower lifetime IQ scores in individuals exposed during childhood. Moreover, it has been linked to lower impulse control and increased violence. In fact, research suggests that the rise and fall of crime rates in the industrialized world during the late 60s to the 90s can be attributed to the use of leaded gasoline. The decision to introduce and later remove lead from gasoline had far-reaching consequences.
Dr. Ted Schwaba from the University of Texas, Austin, embarked on a study to investigate whether lead exposure also influences adults’ personalities, specifically the “Big Five” traits. Using lead measurements in the childhood neighborhoods of 1.5 million people across America and Europe, Schwaba conducted online personality tests to gather data. The results were eye-opening.
“Our personalities accompany us everywhere,” Schwaba explained. “Even a small negative effect of lead on personality traits, when multiplied across millions of people and their daily decisions and behaviors influenced by personality, can have massive impacts on well-being, productivity, and longevity.” This study is particularly significant because previous research has only explored modest lead-induced effects on personality traits within a limited scope.
Schwaba and his team discovered that adults who grew up in counties with high lead levels exhibited less healthy personalities. While this finding could be influenced by various factors, such as urban and rural differences, it is important to note that the phasing out of leaded petrol under the Clean Air Act was not uniform across all areas. Schwaba found that individuals born after lead concentrations in their county decreased experienced benefits that were not observed in counties that transitioned to lead-free petrol later.
Data from Europe, where the phase-out of leaded petrol occurred later, supported two of Schwaba’s main findings. Lead exposure was associated with greater neuroticism and lower agreeableness on both continents. However, the effect on conscientiousness was contradictory, raising doubts about its validity.
“These three traits – neuroticism, agreeableness, and conscientiousness – are crucial components of a mature, psychologically healthy personality. They strongly predict our success or failure in relationships and at work,” Schwaba emphasized. Unfortunately, individuals with high lead exposure struggle to develop and exhibit these traits later in life.
It’s interesting to consider how generational stereotypes often fail to withstand scientific scrutiny. However, if you’ve noticed that Gen X individuals tend to be more neurotic and inclined to complain to the manager, it may be due to their significantly higher lead exposure.
“For a long time, we’ve known that lead exposure is harmful, but each new wave of research reveals additional ways in which it harms society,” Schwaba remarked. While leaded petrol may be a thing of the past, Schwaba highlighted the fact that many lead-lined water pipes still need to be replaced, and significant amounts of topsoil remain contaminated. He also noted that Black children in America are twice as likely to be exposed to lead as their white counterparts.
Schwaba’s work suggests that previous estimates undervalue the potential benefits of further reducing lead exposure. In the United States alone, lowering lead exposure could potentially yield benefits worth $1.2 trillion.
