In The Sensory Order: An Inquiry into the Foundations of Theoretical Psychology (1952), Hayek independently developed a "Hebbian learning" model of learning and memory – an idea which he first conceived in 1920, prior to his study of economics. Hayek's expansion of the "Hebbian synapse" construction into a global brain theory has received continued attention in neuroscience, cognitive science, computer science, behavioural science, and evolutionary psychology, by scientists such as Gerald Edelman, and Joaquin Fuster.