Sigmund Freud
Founder of psychoanalysis who emphasized unconscious processes, childhood experiences, and internal conflicts. He proposed structures of personality (id, ego, superego) and defense mechanisms.
G. Stanley Hall
First American psychologist and founder of the APA. He pioneered developmental psychology and introduced the concept of adolescence.
Donald Hebb
Proposed Hebbian learning, stating that neural connections strengthen through repeated activation. His work linked neuroscience and learning.
William James
Founder of functionalism who emphasized the purpose of consciousness. He wrote The Principles of Psychology and influenced pragmatism.
Carl Rogers
Humanistic psychologist who developed client-centered therapy. He emphasized empathy, genuineness, and unconditional positive regard.
Martin Seligman
Founder of positive psychology and researcher on learned helplessness. His work focuses on well-being, resilience, and optimism.
B. F. Skinner
Behaviorist who studied operant conditioning. He showed how reinforcement and punishment shape behavior.
John B. Watson
Founder of behaviorism who argued psychology should study observable behavior. He demonstrated conditioning with the Little Albert experiment.
Wilhelm Wundt
Established the first psychology laboratory in 1879. He promoted structuralism and the study of conscious experience.
Neal Miller
Integrated learning theory with physiology. He conducted pioneering research on biofeedback.
Robert Rosenthal
Studied expectancy effects in research. He demonstrated the Pygmalion effect in education.
Stanley Schachter
Co-developed the two-factor theory of emotion. He emphasized cognitive interpretation of arousal.
John Atkinson
Developed expectancy–value theory of achievement motivation. He studied motivation to succeed versus fear of failure.
David Buss
Evolutionary psychologist known for research on mating strategies. He studied sexual selection and mate preferences.
Walter Cannon
Proposed the Cannon–Bard theory of emotion. He emphasized simultaneous physiological arousal and emotional experience.
Paul Ekman & Wallace Friesen
Identified universal facial expressions of emotion. They developed the Facial Action Coding System (FACS).
Joseph LeDoux
Researched neural pathways of fear. He distinguished fast and slow emotional processing routes in the brain.
William Masters & Virginia Johnson
Pioneers in scientific research on human sexuality. They described physiological stages of sexual response.
David McClelland
Studied human motivation, including need for achievement, affiliation, and power. He applied motivation theory to leadership.
Henry Murray
Developed the Thematic Apperception Test (TAT). He emphasized personality needs and environmental presses.
Robert Plutchik
Proposed a psychoevolutionary theory of emotion. He identified eight basic emotions arranged in a wheel.
Mary Ainsworth
Developed the Strange Situation to study attachment. She identified secure and insecure attachment styles.
Jay Belsky
Researched parenting and child development. He proposed differential susceptibility to environmental influences.
John Bowlby
Founder of attachment theory. He emphasized the importance of early caregiver bonds.