Hauer and Associate Professor of Sociology Michael McFarland, the study’s lead authors, found that average lead-linked loss in cognitive ability was 2.6 points as of 2015. Though for those born between 1951 and 1980, this number was even greater.

Researchers found that estimated lead-linked deficits were greatest for people born between 1966 and 1970, a population of about 20.8 million people, which experienced an average deficit of 5.9 IQ points per person.
Source: https://news.fsu.edu/news/health-med...ed-to-iq-loss/

This may explain the significent different in opinions between older and younger people.