American psychologist, the third of the three founders of humanistic psychology — with Rollo May and Carl Rogers — and the figure who gave the movement its most widely repeated idea: the hierarchy of needs, arranged from physiological survival, through safety, belonging, and esteem, to the summit of self-actualization. The scheme first appeared in "A Theory of Human Motivation" (1943) and reached its mature form in Motivation and Personality (1954).
Maslow framed this hierarchy as a deliberate alternative to the two dominant American psychologies of his training — Freudian psychoanalysis, which he read as reducing the person to sick or defended drives, and behaviorism, which he read as reducing the person to conditioning. Against both he proposed a psychology that took its cue from the healthy and the exceptional: what, he asked, does a human being look like when need and defense are not the whole story? His method was to study people he judged to be self-actualizing — Lincoln, Jefferson, Whitman, Spinoza, Eleanor Roosevelt among others — and to catalogue their recurrent features: realistic perception, spontaneity, problem-centered rather than self-centered attention, need for privacy, autonomy, freshness of appreciation, peak experiences, Gemeinschaftsgefühl (a concept he took directly from Adler), deep but selective interpersonal relationships, democratic character, ethical certainty, unhostile humor, creativity, resistance to enculturation.
Toward a Psychology of Being (1962) extended this into his late distinction between deficiency motivation (the lower needs, experienced as pulls to fill a lack) and being motivation (the higher reaches, experienced as expression rather than compensation) and to his controversial late concept of peak experiences — transient states of unity, clarity, and joy that he treated as psychological data rather than as religious phenomena, though he allowed that they were what many mystical and religious traditions had been reporting under other names.
Maslow's academic reputation has been mixed — the hierarchy as he stated it has not stood up well to empirical test, and his sample of self-actualizers was small and selected — but his cultural influence has been enormous. The vocabulary of "self-actualization" and "peak experience" passed into general use; the hierarchy diagram is probably the single most widely reproduced image from 20th-century psychology; and through transpersonal psychology, organizational development (Peter Drucker and Douglas McGregor were direct readers), and the human-potential movement at Esalen, his framework shaped mid-century American ideas of growth, management, and well-being. The critique of this framework — from Lasch and others — as underwriting a therapeutic individualism at the expense of moral and political community has been part of the reception from the 1970s on.
Maslow is on the graph because his hierarchy of needs became — for better and worse — the most widely known twentieth-century secular picture of the human good, borrowed by management theory, educational theory, and popular self-help in ways that make him a reference point whether or not the borrowers acknowledge him.