|They proved it scientifically, using double-blind tests. 125 blindfolded men were slapped across the face repeatedly, over a period of three years (while others received equivalent amounts of pain in other ways, as a control). On average, memory retention increased by 2.3%, on a statistically significant basis. The effect wasn’t uniform, though. Some subjects benefitted a lot, but fully 17% of the men receiving the slapping treatment were unable to remember anything at all from their lives before the programme started. There’s obviously a lot still to learn, but the Institute just received a €8 million grant, so research continues.