In 1937 Anastasi wrote a book about the role of genes and environment and how it affects people. During this time, this issue caused many arguments. Anne believed that labeling psychological traits, like intelligence, was unreliable because of the current methods used to define and measure was wrong. This caused Anne to change the way people define psychological traits and how it was measured. Her main theory on the matter is that people should understand how genetic works first before defining psychological traits because they can be wrong.