>>3975002>In the 1950s, the psychologist Peter Milner created an experiment where a rat pressing a lever would deliver direct stimulation to the pleasure center of the rat's brain.What resulted was perhaps the most dramatic experiment in the history of behavioral neuroscience
>Rats would press the lever as many as 7,000 times per hour to stimulate their brains. This was a pleasure center, a reward circuit, the activation of which was much more powerful than any natural stimulus.>Subsequent experiments revealed that rats preferred pleasure circuit stimulation to food (even when they were hungry) and water (even when they were thirsty).Self-stimulating male rats would ignore a female in heat and would repeatedly cross foot-shock-delivering floor grids to reach the lever.
>Some rats would self-stimulate as often as 2000 times per hour for 24 hours, to the exclusion of all other activities.>They had to be unhooked from the apparatus to prevent death by self-starvation. Pressing that lever became their entire world. 