The Ed Norton Effect is a theory in which the idea that you cannot judge a book by its cover is applied to a fighting scenario.

It has long been taught by martial arts instructors and veteran bar brawlers alike that the look of an opponent cannot be used to judge his fighting prowess.

The above idea is exemplified by hollywood actor/director Ed Norton. In the film American History X Norton portrays a reformed skinhead. The picture frequently flashes back to his days of running with the skins and in those scense he looks like the devil himself. With a clean shaven head, goatee, nazi tattoos, and a powerful physique Norton looks like quite a force to reckoned with and his image could invoke fear in many people.

Now let us take Ed Norton in the comedy Keeping the Faith in which he co-stars with Ben Stiller. Norton plays a bumbling priest with a clean cut look in this film, which he also directed. As a matter of fact, if this was the first time someone saw Ed Norton, they might find him almost dorky.

The fact of the matter is that when we see someone that appears a certain way, the stereotypes that we carry fill in the information that we do not know for sure. In the case of Norton in American History X, we see a skinhead. Many people associate skinheads with violence, especially the neo nazi variety. Yet even if one were inclined to violence, it does not mean that they have an extraordinary ability to carry themselves in a fight.

Let us examine this theory cross-culturally. In western culture, when there is agression between two people, they tend to stick out their chests in a display of power. This is becuase we equate upper body strength with fighting ability. We think of power as an upside-down triangle. In Japan when children are in a scuffle, they puff out their bellies (which symbolizes a sumo wrestler) and take a deep stance. They do this becuase to thier culture, power is derived from a powerful stance. Power is thought of in a right-side up triangle.