Two UT researchers found that lead exposure in childhood is correlated to people having “less adaptive” personalities as adults. 

The researchers conducted a study published July 20 that used an online questionnaire to map the personalities of around 1.5 million adults across the United States and Europe to their childhood atmospheric lead exposure by analyzing lead exposure levels in the areas they grew up. 

“The general findings of this study are that across the U.S. and across Europe, people who are exposed to more atmospheric lead grew up to have less adaptive personality profiles.” said Ted Schwaba, a postdoctoral researcher.

The researchers also looked at the effects of the Clean Air Act of 1970, which allowed federal and state regulations to limit harmful emissions in order to further strengthen their conclusion that lead exposure is harmful to personality development.

“We looked at people’s personalities of those born in a county before lead was phased out and after the lead was phased out,” Schwaba said. “And people born after the lead exposure started going down had more mature and adaptive personalities.” 

Despite efforts to reduce lead exposure by getting rid of atmospheric lead, Schwaba said many people are still exposed and there are racial and economic disparities among the exposures. 

“In wealthier neighborhoods, where they could replace lead pipes and live in an area that wasn’t industrial, people are no longer being exposed to lead,” Schwaba said. “But people of color, who are living in more industrialized or formerly industrialized areas where they’re not replacing the lead pipes, are still being exposed to lead. Some people are being affected more than others, and it’s really giving them disadvantages that will carry throughout their whole lives.”

Schwaba said most research on lead exposure in the past has studied the effects of high levels of lead exposure. However, he said lower levels of lead exposure can also be dangerous. 

“Back in the 1960s and 70s, research was focused on lead poisoning and the negative effects

of that,” Schwaba said. “But then people started researching what happens when you have lower levels of lead exposure and they found negative effects on people who didn’t even have high levels of lead in their blood. The piece of the puzzle that I’m trying to fit in for this study is to examine what happens perhaps not even at the clinical level, but at the level of normal range personality traits.”

Psychology professor Samuel Gosling said this study underlined the value of reducing lead exposure and the impact of lead on something as broad and complex as personality.

“This data set, which has been around since the 90s, now allows us to begin to look at these long term effects,” said Gosling.