Key Psychological Theorists

Why This Matters

Understanding psychology's major theorists isn't just about memorizing names and dates—it's about grasping the fundamental debates that define the field. You're being tested on how these thinkers answered the big questions: What drives human behavior? How do we learn? What shapes personality? How much does environment matter versus biology? Each theorist represents a different perspective, and the AP exam loves asking you to compare their approaches or apply their concepts to novel scenarios.

These theorists also demonstrate how psychology evolved as a science. From Wundt's first laboratory to modern cognitive-behavioral approaches, you'll see shifts from introspection to behaviorism to cognition—and the exam expects you to know why those shifts happened. Don't just memorize what each person believed; understand which psychological perspective they represent and how their ideas connect to the broader curriculum. That's what earns you points on FRQs.

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Founders of the Discipline

Psychology had to establish itself as a science separate from philosophy. These pioneers created the methods and frameworks that made modern psychology possible.

Wilhelm Wundt

• Founded the first psychology laboratory in 1879—this date marks psychology's official birth as an experimental science
• Introspection was his primary method, asking trained observers to report their conscious experiences systematically
• Structuralism emerged from his work, attempting to break down consciousness into its basic elements

William James

• Functionalism was his major contribution—asking why we think and behave, not just what we experience
• Stream of consciousness described his view that mental life flows continuously rather than existing as discrete units
• Pragmatic approach emphasized the practical, adaptive purposes of mental processes, influencing American psychology's applied focus

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Learning and Behaviorism

Behaviorists revolutionized psychology by insisting that only observable behavior—not internal mental states—could be studied scientifically. Their core principle: behavior is shaped by environmental consequences.

Ivan Pavlov

• Classical conditioning was discovered through his famous dog experiments—pairing a neutral stimulus with an unconditioned stimulus
• Key terms to know: unconditioned stimulus (US), unconditioned response (UR), conditioned stimulus (CS), conditioned response (CR)
• Foundation for behaviorism—his work showed that reflexive responses could be learned, not just inherited

John B. Watson

• Father of behaviorism who declared psychology must study only observable behavior, rejecting introspection entirely
• Little Albert experiment demonstrated that emotional responses (fear) could be classically conditioned in humans
• Environmental determinism—his famous claim that he could shape any child into any type of person given control of their environment

B.F. Skinner

• Operant conditioning explained how voluntary behaviors are shaped through reinforcement and punishment
• Skinner Box (operant chamber) allowed precise measurement of how consequences affect behavior in controlled settings
• Reinforcement schedules (fixed/variable, ratio/interval) predict different patterns of behavior—know these for the exam

Albert Bandura

• Social learning theory (later social cognitive theory) showed that learning occurs through observation, not just direct reinforcement
• Bobo doll experiment demonstrated that children imitate aggressive behavior they observe in adults—even without reinforcement
• Self-efficacy refers to belief in one's ability to succeed, which powerfully influences motivation and behavior

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Developmental Theorists

These psychologists mapped how humans change across the lifespan. Their shared insight: development follows predictable stages, though they disagreed on what drives progression.

Jean Piaget

• Cognitive development theory proposed four stages: sensorimotor, preoperational, concrete operational, and formal operational
• Schemas, assimilation, and accommodation describe how children organize and adapt their understanding of the world
• Active learning emphasis—children construct knowledge through interaction with their environment, not passive absorption

Erik Erikson

• Psychosocial development spans eight stages from infancy through late adulthood—unlike Freud, development doesn't stop in childhood
• Each stage presents a crisis (e.g., trust vs. mistrust, identity vs. role confusion) that must be resolved for healthy development
• Social and cultural influences shape personality, expanding beyond Freud's focus on biological drives

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Personality and the Unconscious

Freud's psychoanalytic approach dominated early personality theory, proposing that unconscious forces drive behavior. His influence persists even as many of his specific claims have been challenged.

Sigmund Freud

• Psychoanalysis emphasized that unconscious conflicts—especially from childhood—shape adult behavior and personality
• Structural model of personality: id (pleasure principle), ego (reality principle), and superego (morality/conscience)
• Psychosexual stages (oral, anal, phallic, latency, genital) proposed that fixation at any stage affects adult personality

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Humanistic Psychology

Humanistic psychologists rejected both behaviorism's environmental determinism and psychoanalysis's focus on dysfunction. Their core belief: humans are inherently good and motivated toward growth.

Abraham Maslow

• Hierarchy of needs arranges human motivations from basic (physiological, safety) to higher-order (belonging, esteem, self-actualization)
• Self-actualization represents achieving one's full potential—the pinnacle of psychological health
• Third force psychology—humanistic approaches emerged as an alternative to behaviorism and psychoanalysis

Carl Rogers

• Client-centered therapy (person-centered) emphasized empathy, genuineness, and unconditional positive regard from the therapist
• Self-concept is central to personality—psychological problems arise when there's incongruence between self-concept and experience
• Conditions of worth describe how conditional acceptance from others can distort self-concept and block growth

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Cognitive and Clinical Approaches

Cognitive psychologists brought mental processes back into scientific psychology, while clinical researchers developed evidence-based treatments.

Aaron Beck

• Cognitive therapy targets distorted thinking patterns that contribute to depression and anxiety
• Cognitive triad identifies three types of negative thinking: about the self, the world, and the future
• Foundation for CBT—cognitive-behavioral therapy combines Beck's cognitive restructuring with behavioral techniques

Elizabeth Loftus

• Memory malleability research demonstrated that memories can be altered, created, or distorted after the fact
• Misinformation effect shows how post-event information can contaminate eyewitness memory
• Legal implications—her work has transformed how courts evaluate eyewitness testimony reliability

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Social Psychology Pioneers

Social psychologists study how situations and social contexts influence behavior. Their key insight: the power of the situation often overrides individual personality traits.

Stanley Milgram

• Obedience experiments showed that 65% of participants administered what they believed were dangerous shocks when ordered by an authority figure
• Situational power demonstrated that ordinary people will harm others under certain conditions—not just "evil" individuals
• Ethical controversy raised important questions about participant welfare that shaped modern research ethics guidelines

Philip Zimbardo

• Stanford prison experiment showed how assigned roles (guard vs. prisoner) rapidly produced abusive behavior
• Situational attribution emphasized—the prison environment, not personality, explained the guards' cruelty
• Deindividuation and dehumanization concepts emerged from understanding how anonymity and power corrupt behavior

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Quick Reference Table

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Self-Check Questions

1. Both Piaget and Erikson proposed stage theories of development. What is the key difference in what each theorist believed developed through stages?

2. A child watches an older sibling get praised for sharing toys, then begins sharing more often. Which theorist's work best explains this, and how does it differ from Skinner's operant conditioning?

3. Compare the approaches of Freud and Beck to treating psychological disorders. How do their assumptions about the source of problems differ?

4. Milgram and Zimbardo both conducted studies with significant ethical concerns. What common conclusion about human behavior did their research support, and how might you use both studies to answer an FRQ about situational influences on behavior?

5. A therapist tells a client, "I accept you completely as you are, and I believe you have the capacity to grow." Which theorist's approach does this reflect, and what key concepts from their theory are being applied?