The cultural context found in the turn-of-the-millennium West seems to have been exceptionally conducive to the development of eating disorders. It should be remembered that there are cases in which the awareness that comes with self-categorization might mitigate the trouble that a disorder causes. Although the groups with which young adults affiliate themselves typically predate their naming, none of those groups exists independently of the categorization practices in which those names are applied. Such groups emerge from the tendency to apply categorizations to themselves and to one another, and from the tendency to use such categorizations when making sense of one another’s behavior. Positive feedback loops reinforce themselves, the people who do think of themselves as belonging to categories can become more likely to display extreme forms of traits that would otherwise be normally distributed. In the case of psychiatric diagnoses, the extremities begotten by these feedback loops are less benign.