In 1954, two researchers at Canada's McGill University accidentally discovered how humans learn to repeat conduct that's useful to our survival. An electrode implanted within the mind of a rat had slipped from its supposed place and had come to relaxation on the medial forebrain bundle, a bunch of nerve cells that leads from deep in the mind to the prefrontal cortex. Upon delivering a collection of electrical shocks to the electrode, the rat displayed a eager curiosity in the realm of its box it had been exploring when it acquired the primary jolt. Upon additional investigation, Olds and Milner realized that what they'd found was the brain's reward center, a system of regions associated with delivering a way of pleasure in return for certain behaviors like eating and mating. This discovery was revolutionary