the types of clothes they should wear. Girls who internalize the beliefs that they must be attractive to men may spend more time on makeup and focus less on academics. Other research has examined the formation of intergroup attitudes among students in school settings. Bigler speaks strongly about how models provided to children contribute to social stereotyping and prejudice among children as they grow up. To Bigler, saying "Good morning boys and girls" is similar to saying "Good morning blacks and whites" as it draws attention to social categories that result in children viewing themselves and others differently. In a widely cited study, Bigler examined gender stereotyping in relation to classroom practices. In some classes, the teacher referred to students by gender ("boys" vs. "girls") while, in others classes, the teacher referred to mixed gender groups according to t-shirt colors ("red" or blue"). Teachers were explicitly instructed not to favor or show preference to one group of children over the other. After four weeks, children in classes where they were referred to as "boys and girls" showed increased gender stereotyping, whereas no change was observed in classes that used t-shirt colors to distinguish groups. Teachers may unknowingly impose gender stereotypes upon their pupils when they refer children as boys and girls. Such language appears to create tensions in the classroom that impact how children view and treat one another. Selected publications Bigler, R. S. (1995). The role of classification skill in moderating environmental influences on children's gender stereotyping: A study of the functional use of gender in the classroom. Child Development, 66(4), 1072–1087. Bigler, R. S., Jones, L. C., & Lobliner, D. B. (1997). Social categorization and the formation of intergroup attitudes in children. Child Development, 68(3), 530–543. Bigler, R. S., & Liben, L. S. (2007). Developmental intergroup theory: Explaining and reducing children's social stereotyping and prejudice. Current Directions in Psychological Science, 16(3), 162–166. Hyde, J. S., Bigler, R. S., Joel, D., Tate, C. C., & van Anders, S. M. (2018). The future of sex and gender in psychology: Five challenges to the gender binary. American Psychologist. https://dx.doi.org/10.1037/amp0000307 Liben, L. S., & Bigler, R. S. (2002). The developmental course of gender differentiation: Conceptualizing, measuring, and evaluating constructs and pathways. Monographs of the society for research in child development, i-183. Signaler, M. L., Bigler, R. S., & Liben, L. S. (1993). Developmental differences in children′ s gender schemata about others: A