The behavioral establishment's response to Harlow's puzzle findings was largely to ignore them. The framework did not have a vocabulary for intrinsic motivation, and the finding that contradicted the framework could not easily be incorporated into it.
Harlow's contribution to motivation science was the demonstration that a drive existed beyond biology and behavioral conditioning. What that drive was, how it operated, and under what conditions it flourished would take another thirty years of research to specify.
Edward Deci and Richard Ryan, building on Harlow's foundation, developed self-determination theory across the 1970s and 1980s, producing the empirical architecture that Pink later synthesized into his three-pillar framework.
Harlow was born in Fairfield, Iowa, in 1905 and spent his academic career at the University of Wisconsin–Madison, where he established the primate laboratory that produced his most consequential work.
His 1949 paper 'Learning Motivated by a Manipulation Drive' reported the puzzle experiments. His 1958 address 'The Nature of Love' presented the maternal-deprivation work that became both famous and ethically contested.
Intrinsic reward coined. Harlow named the phenomenon that contradicted behaviorism's framework.
External reward can diminish performance. Food rewards reduced rather than enhanced puzzle-solving — an early demonstration of what became the overjustification effect.
The animal evidence matters. Intrinsic motivation appears in non-human primates, suggesting it is not merely a cultural construct.
Foundation for later work. Deci, Ryan, Amabile, and Pink all built on Harlow's original empirical demonstration.