What unwritten social codes exist in the society in To Kill a Mockingbird?
The most obvious social codes involve African Americans. No blacks live in the downtown area of Maycomb; they are segregated in the Quarters outside of town. There are separate churches for whites and blacks, and the school which Jem and Scout attend is no doubt segregated; in fact, there is no mention of a school for Maycomb's black children. At Calpurnia's church, most of the congregation shows polite deference to Jem and Scout: It is in part because they are guests at the church, but it is also because such behavior is expected. Blacks are not usually welcome in a white person's house unless they are employees, like Cal and Sophy. Tom is hesitant to go inside the Ewell house, and Scout mentions during the trial that no "respectable Negro" would enter a white man's yard without permission. Before the trial, the Negroes wait until all of the white people have entered the courtroom; they enter afterward and must sit separately in the balcony. During the trial, Tom is always careful to address Atticus and Gilmer as "sir"; however, Gilmer repeatedly calls Tom "boy," an act which receives no objections from either Atticus or the judge. The Ewells charge Tom with rape in part because of the embarrassment Bob and Mayella may receive if it is found that she tried to seduce Tom. Dolphus Raymond is scorned because of his preference for Negro friends and women. His "mixed chillun"
"... don't belong anywhere. Colored folks won't have 'em 'cause they're half white; white folks won't have 'em 'cause they're colored, so they're just in-betweens..."
Other standard practices of the time which are not mentioned in the story are segregated restaurants, bathrooms, hotels and, sometimes, businesses.
One of the basic unwritten social codes is that whites are above the African Americans in Maycomb. This is seen when Atticus loses the court case. According to Jem, Atticus does an excellent job of making Tom seem innocent. However, the jury still finds Tom guilty because he is black. Other examples are when Mr. Ewell describes in court how the value of his property is decreasing because there are African Americans living around him. Also when Aunt Alexandra scolds Atticus for mentioning how a neighbor dislikes black people in front of Calpurnia.