How do social group concepts develop in childhood? How do they guide the perception of others? What are some of their real-world consequences? These questions frame my research. Specifically, I explore beliefs about race and multiracial individuals, how concepts of group norms contribute to social cognition, and the implications of cognitive biases for social outcomes. I recruit racially and ethnically diverse samples to examine the effects of group membership on social cognition and use a variety of experimental and survey methods with both child and adult participants. My work is grounded in theories of conceptual development and group-based inequality, and shows that group concepts are early emerging, strengthened across development, shaped by social experiences, inductively powerful, and highly consequential.