Ralph Burger, who ran A&P, dedicated himself to carrying on the company tradition, regardless of evidence that it was a doomed strategy...What A&P did is not uncommon, whether in business, in science, or even in the wilderness. Behavior like that, seemingly contrary and nonsensical, stems at least in part from a phenomenon that psychologists call “groupness.” Coined by a social psychologist at Oxford University named Henri Tajfel, the term refers to the tendency of various animals, including humans, to form in-groups. When the in-group encounters individuals from outside the group, the default response is hostility. People protect their group from outsiders and from outside influences. For example, we will reject information, habits, and culture from other groups...The official report on the crash of Columbia said, “External criticism and doubt . . . reinforced the will to ‘impose the party line vision on the environment, not to reconsider it . . .’ This in turn led to ‘flawed decision making, self deception, introversion and diminished curiosity about the world outside the perfect place.’”