Read this article to learn about what happened in the Austin (Texas) School District in 1971 shortly after schools there were racially integrated. Students had been segregated until this time, and the difference in quality among their former schools had put them on different ability levels. Teachers struggled to reach all students, who began to compete to have tailored instruction - usually advanced instruction for white students and remediation for minority students. This unspoken competition between whites and minorities led to inter-racial competitive attitudes and eventually violence on school grounds.
Teachers can inadvertently set up inter-racial competition in the classroom by using race and ethnicity to track students or to sort them into socially homogeneous learning groups. Students already and unwittingly bring enough racial, sexist, nationalistic, and other types of negative socialization into the classroom. Muzafer Sherif and his researchers showed in their historic Robbers Cave experiment in 1954 that just putting children of different groups into contact with each other does not guarantee an improvement of inter-group relations.