To the best of my knowledge, the first person to explicitly represent a mediator with a diagram was a Stanford graduate student named Barbara Burks, in 1926. This very little-known pioneer in women’s science is one of the true heroes of this book. There is reason to believe that she actually invented path diagrams independently of Sewall Wright. And in regard to mediation, she was ahead of Wright and decades ahead of her time. Burks’s main research interest, throughout her unfortunately brief career, was the role of nature versus nurture in determining human intelligence.
