In 1972, a Stanford University psychology professor named Walter Mischel ran an incredible experiment. A child was given a small treat - in this case they could choose between a Marshmallow or a pretzel (whichever they preferred). They were told that they could eat the treat any time they liked, or.... if they managed not to eat the treat and waited for the researcher to return 15 minutes later, they could have a second one. The researcher left the room and watched with interest.   So what happened?     Well, as you may have guessed some of the…