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After decades of behaviorism, self-determination theory offered a new model of what a human being is.

Human motivation is not a black box; we are active agents striving for autonomy, competence, and relatedness.

Research shows that autonomy, competence, and relatedness are foundational human needs, all over the world.

Psychologist Edward L. Deci died on Feb. 14, 2026. He was 83. His loss is humanity’s loss. His life was humanity’s great gain.

If you ever felt your motivation drain away under a micromanaging boss, he gave you the language for what was happening to you. If you ever sensed that grades and gold stars were somehow diminishing the very learning they were supposed to enhance, he explained why.

And in doing so, he helped liberate psychology from one of its most limiting assumptions.

The Black Box of Behaviorism

For much of the 20th century, the dominant paradigm in psychological research, behaviorism, treated humans as input-output machines. Organisms did things because of rewards and punishments. The inner life of wanting, wondering, striving, and caring was called the “black box.” Scientifically irrelevant and not to be opened.

There were cracks in this box before Deci. In 1950, Harry Harlow reported that rhesus monkeys learned to solve mechanical puzzles on their own, and introducing food rewards actually decreased spontaneous exploration.

In the behaviorist framework, this was unexpected—adding rewards should add motivation.

The monkeys, inconveniently, disagreed.

But Harlow moved on to attachment experiments, and the idea of intrinsic motivation largely went dormant.

Studying Intrinsic Motivation

In 1971, Edward Deci published a study that challenged motivation science. College students spent three sessions working on the SOMA cube, a spatial puzzle that can be assembled into various shapes. During the second session, some students were paid for each puzzle they solved, while others were not. The real test came in the third, “free‑choice” session, when participants believed they........

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