““This habit starts awfully early. Social psychologist Marilynn Brewer, who has been studying the nature of stereotypes for many years, once reported that her daughter returned from kindergarten complaining that “boys are crybabies.”25 The child’s evidence was that she had seen two boys crying on their first day away from home. Brewer, ever the scientist, asked whether there hadn’t also been little girls who cried. “Oh yes,” said her daughter. “But only some girls cry. I didn’t cry.” Brewer’s little girl was already dividing the world, as everyone does, into us and them. Us is the most fundamental social category in the brain’s organizing system, and it’s hardwired.””
