Epstein is also a scholar in the field of psychological maturity, and once published an online maturity test. He is critical of what he sees as the "artificial extension of childhood" over the past century, arguing that what society views as the "teen brain" is often the result of Western cultural factors and infantilization, rather than a set of brain characteristics that are inherent in all humans throughout their teen years. In certain essays, he has cited studies which found that some teenagers are in some ways more developmentally mature than most adults, and advocates giving young people more adult responsibility, as well as placing them in environments in which they will not be prone to socializing simply with other teenagers.