Who was the functionalist who authored the textbook principles of psychology for the emerging discipline of psychology?

William James

Explanation:

William James was born in New York in 1842, and died in 1910 at his country house in the American city of Chocoronua. He studied philosophy at the University of Berlin from 1867 to 1868. The following year, he earned a degree in medicine from Harvard, becoming a professor of physiology and anatomy from 1873, and then of psychology and philosophy at the same university. As a philosopher, he was responsible for what is considered America's greatest contribution to philosophy: pragmatism.

James's first as a psychologist had as a starting point the creation of a small psychology laboratory in 1875 at Harvard University; and his first psychology course, on "The Relationships between Physiology and Psychology." In this period the culmination of his theoretical production is the publication, in 1890, after 12 years of thorough elaboration, published the book "The Principle of Psychology". This book (over a thousand pages in length) contains James' main ideas on topics such as "habit", "attention", "thought flow" and "self".

the answer is shoe size