In 1954, two researchers at Canada’s McGill University by chance discovered how humans be taught to repeat habits that’s helpful to our survival. An electrode implanted in the brain of a rat had slipped from its meant 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 series of electrical shocks to the electrode, the rat displayed a keen interest in the area of its box it had been exploring when it received the first jolt. Upon additional investigation, Olds and Milner realized that what they’d discovered was the mind’s reward heart, a system of areas related to delivering a sense of pleasure in return for certain behaviors like eating and mating. This discovery was revolutionary