These three aspects are determinant in one's perception of the world. Although they don't shape every aspect of it, they have a major role. The socioeconomic status refers to the social standing or class an individual belongs. Depending on his/her status, the individual will face different problems or events during his life. As a consequence some concerns may become general to people belonging to a determinate status. The cultural background, the cultural context in which a person develops, including the heritage and primary education, will also teach the individual how to behave and how to respond to certain things. From spititual things (believing in god or buda) to praxis (eating pasta or rice), cultural background will help shape the way someone is. The same happens with gender or the social construction definition of men and women, if you are a boy you would probably be taught to be brave, active and dominant, if you are a woman, you will be taught to be delicate and sentimental.
These three aspects work together to shape our perception of the world, they don't only shape it, they also shape the way others see and treat you.
Cherry listens to Johnny's story about his beating and she say that "not all Soc's are like that" and Pony boy agrees saying "not all greasers are like Dally (he was acting rude toward the two Soc's)" They both agree that not all socs are the same and not all greasers are the same.