Sigmund Freud; leading figure in Psychoanalysis.
Chapter one covered an interesting array of topics that discussed the basic principles of psychology, schools of thought in psychology, and how to think scientifically. The main point was "insist on evidence". It discusses how everyone is different and makes decisions based on multiple variables. As scientific thinkers, people try to think objectively and take out belief perseverance and confirmation bias. Also, you should be on your guard to interpret metaphysical claims and pseudoscience. The point is not to be cynical and closed minded, but show scientific skepticism. Scientists must know the six scientific thinking principles: Ruling out rival hypothesis, correlation isn't causation, falsifiability, replicability, extraordinary claims require extraordinary evidence, and Occam's razor. I always hear extraordinary claims from weight loss programs claiming that you can lose fifty pounds without hard work. Psychology has several schools, including functionalism, behaviorism, cognitive psychology, and psychoanalysis. Psychology is constantly changing and being argued upon. Some schools believe it is based on incentives, like behaviorism, and others believe it's what goes on inside your head, like cognitive psychology. It is believed by most that Psychology is made up by not one but many major schools of thought.