The Theorists Behind the Psychological Foundations Section
The names the MCAT expects test-takers to know in psychology span more than a century of theory, much of it built through direct disagreement between successive thinkers. Sigmund Freud’s psychoanalytic theory, developed from the 1890s through the early twentieth century, proposed that unconscious drives and childhood experience shape adult personality and behavior — a framework that dominated psychology for decades before later researchers challenged its lack of testability. Jean Piaget, working in Switzerland starting in the 1920s, took a different approach entirely, proposing that children move through four distinct stages of cognitive development — sensorimotor, preoperational, concrete operational, and formal operational — based on careful observation of how children of different ages solved problems, including his own three children. Erik Erikson later extended the idea of developmental stages across the entire human lifespan rather than stopping at adolescence, describing eight stages, each centered on a particular psychosocial conflict, from trust versus mistrust in infancy to integrity versus despair in old age.
A separate tradition in psychology moved away from internal mental states entirely and toward observable behavior. Ivan Pavlov, a Russian physiologist studying digestion in dogs in the 1890s, noticed almost by accident that his dogs began salivating at the sound of a bell that had repeatedly preceded feeding — the discovery of classical conditioning, in which a neutral stimulus becomes associated with an automatic response. American psychologist B.F. Skinner built on that foundation decades later with operant conditioning, demonstrating through his famous “Skinner box” experiments that behavior could be shaped through reinforcement and punishment, a framework that remains foundational to how psychologists describe learned behavior.
Social psychology added a further dimension the MCAT tests separately: how group context and authority shape individual behavior. Psychologist Stanley Milgram’s controversial 1961 obedience experiments, conducted at Yale in the shadow of the Nuremberg trials, found that a striking majority of participants would administer what they believed were dangerous electric shocks to another person simply because an authority figure in a lab coat instructed them to continue — a result that reshaped how psychologists understood the power of situational authority over individual conscience, and one that also prompted lasting changes to research ethics standards governing how experiments involving human participants may be designed.
The Biopsychosocial Model and Why the MCAT Added a Social Science Section
Psychiatrist George Engel proposed the biopsychosocial model in a 1977 paper, arguing that health and illness could not be fully understood through biology alone — psychological factors like stress and behavior, and social factors like relationships, culture, and socioeconomic status, all interact with biological disease processes to shape a person’s health. Engel’s model was a direct challenge to what he called the “biomedical model,” the dominant assumption that disease was purely a biological malfunction to be treated with purely biological tools.
That same reasoning is why the Association of American Medical Colleges restructured the MCAT in 2015, adding an entirely new section — Psychological, Social, and Biological Foundations of Behavior — where none had existed before. The addition reflected a growing consensus within medical education that understanding how social and behavioral factors shape health outcomes was just as essential to training a competent physician as understanding biochemistry, and it made psychology and sociology, for the first time, a formally tested part of the path to medical school rather than an assumed prerequisite.
Source: National Institutes of Health (NIH) and Encyclopaedia Britannica.