Aaron Temkin Beck (July 18, 1921 – November 1, 2021) was an American psychiatrist who was a professor in the department of psychiatry at the University of Pennsylvania.

At the time of Aaron's birth, the Temkin-Becks lived a "comfortable, lower-middle class lifestyle" and were in the process of putting down roots on Providence's East Side.

[15] However, due to a shortage of psychiatry residents, he was instructed to do a six-month rotation in that field, and he became absorbed in psychoanalysis, despite initial wariness.

[15] After completing his medical internships and residencies from 1946 to 1950, Beck became a fellow in psychiatry at the Austen Riggs Center, a private mental hospital in the mountains of Stockbridge, Massachusetts, until 1952.

[16] At that time, it was a center of ego psychology with an unusual degree of collaboration between psychiatrists and psychologists, including David Rapaport.

[19][20] The department chair was Kenneth Ellmaker Appel,[21] a psychoanalyst who was president of the American Psychiatric Association,[22] whose efforts to expand the presence and relatedness of psychiatry had a big influence on Beck's career.

[24] Beck's first research was with Leon J. Saul, a psychoanalyst known for unusual methods such as therapy by telephone or setting homework, who had developed inventory questionnaires to quantify ego processes in the manifest content of dreams (that which can be directly reported by the dreamer).

[24] In another experiment, he found that depressed patients sought encouragement or improvement following disapproval, rather than seeking out suffering and failure as predicted by the Freudian anger-turned-inwards theory.

[24] In 1961, however, controversy over whom to appoint the new chair of psychiatry—specifically, fierce psychoanalytic opposition to the favored choice of biomedical researcher Eli Robins—brought matters to a head, an early skirmish in a power shift away from psychoanalysis nationally.

[24] Stunkard, a behaviorist who specialized in obesity and who had dropped out of psychoanalytic training, was eventually appointed department head in the face of sustained opposition which again Beck would not engage in, putting him at bitter odds with his friend Stein.

[15][24] Beck usually explained his increasing belief in his cognitive model by reference to a patient he had been listening to for a year at the Penn clinic.

[15] When he suggested she was anxious due to her ego being confronted by her sexual impulses, and asked her whether she believed this when she did not seem convinced, she said she was actually worried that she was being boring, and that she thought this often and with everyone.

[24] Beck's notebooks were also filled with self-analysis, where at least twice a day for several years he wrote out his own "negative" (later "automatic") thoughts, rated with a percentile belief score, classified and restructured.

[32] In 1967, becoming active again at University of Pennsylvania, Beck still described himself and his new therapy (as he always would quietly) as neo-Freudian in the ego psychology school, albeit focused on interactions with the environment rather than internal drives.

[24] With a monograph on depression that Beck published in 1967, according to historian Rachael Rosner: "Cognitive Therapy entered the marketplace as a corrective experimentalist psychological framework both for himself and his patients and for his fellow psychiatrists.

[34] He termed these cognitions "automatic thoughts", and discovered that their content fell into three categories: negative ideas about oneself, the world, and the future.

[35] Beck explained that successful interventions will educate a person to understand and become aware of their distorted thinking, and how to challenge its effects.

[39][40] Although Beck's approach has sometimes been criticized as too mechanistic, modern CBT stresses the importance of a warm and encouraging therapeutic relationship and tailoring treatment to the specific challenges of each individual.

[41] Beck's work was presented as a far more scientific and experimentally-based development than psychoanalysis (while being less reductive than behaviorism), Beck's key principles were not necessarily based on the general findings and models of cognitive psychology or neuroscience developing at that time but were derived from personal clinical observations and interpretations in his therapy office.