Supernormal Stimuli

In Kessler's The End of Overeating, we are introduced to the concept of a “supernormal” stimulus. A stimulus is defined as supernormal when it is both in excess of normal stimulation levels and not available in nature. For example, the neurobiologist John Staddon found that birds consistently chose to sit on the largest egg available for roosting, even if that egg was from a different species and far too large for the roosting bird to have lain. Even humans are highly susceptible to supernormal stimuli; this can be seen in the seemingly exponential spread of sugar, salt, and fat in the human diet. This mix of tastes is very rare in nature, but has become a staple of cooking. The human brain is hard wired to desire these tastes, because they represent substances that can give lots of energy. Supernormal stimulation can also be seen in the massive spread of mixing foods and using toppings; many staples of the modern diet, from cereal to burgers, are made of out of many diverse ingredients and intentionally designed to capitalize on supernormal stimuli. It is directly because of this that it can be so hard to eat sensibly – evolution has programmed us not to.