Why do children learn in different ways: some are good students who show interest and zeal, while others are lazy and have to be taught against their will? Why do schools have over- and underachievers? Of course, there are a multitude of reasons. But almost 50 years ago it was shown using large data sets that families with high socioeconomic status are more likely to have children who are good students. Of course, there are many examples of successful students from poor families. However, they tend to be the exception to the rule. The certainty of success in school increases with rising socioeconomic status. [Translated by Kenneth Cargill.]