Hebb

Donald Olding Hebb (1904–1985) was a Canadian psychologist who shaped modern theories of learning and memory. In his 1949 work The Organization of Behavior, he proposed what is now called the Hebbian theory. The central postulate, commonly summarized as “neurons that fire together wire together,” states that when a presynaptic neuron repeatedly contributes to the firing of a postsynaptic neuron, the synaptic connection between them strengthens. The strengthening is most effective when the presynaptic activation reliably precedes the postsynaptic response within a short time window.

Hebb’s ideas extended to the concept of cell assemblies—groups of neurons that become linked through experience to represent objects, ideas, or memories. The Hebbian rule has influenced diverse fields, including physiology, psychology, and computational modeling, and it underpins many neural network theories in artificial intelligence. It also foreshadowed later demonstrations of synaptic plasticity, such as long-term potentiation, and remains a foundational principle in discussions of learning and memory.

Biography and legacy: Hebb conducted significant research in Canada and contributed to the development of neuropsychology and cognitive neuroscience. His theoretical framework emphasizes how repetitive, correlated activity in neural circuits can reorganize the brain’s connectivity, shaping behavior. The Hebbian concept continues to influence experimental neuroscience, computational neuroscience, and AI as a basic mechanism by which learning and memory may emerge from patterns of neural activity.