Dr. Donelson R. Forsyth, a social and personality psychologist who teaches at The University of Richmond, told The Daily Beast that this behavior tracks with a typical human behavior known as the “social categorization theory.” “We very naturally put everyone we meet into psychologically constructed categories, and that includes ourselves. In the classic studies of this tendency, researchers would bring in people to a room and divide them into two groups—totally at random," he explained in an email. "Immediately, people would start to identify with their own group, and view the people in the other group negatively. Even without ever talking to one another, people assume they are in the ‘good group’ and that there is something wrong with the people in the other group.”... But getting a vaccine is not just a friendly (or not) status symbol. It’s literally about life or death. You’d think that having enough shots to go around so that everyone who needs or wants one could get one would actually stifle our exclusive nature, but a Notre Dame paper titled The Psychology of Competition: A Social Comparison Perspective suggests that having fewer options actually heightens the divide.