What topic does the speaker explain in details?

Certain phrases one commonly bears among Americans capture their devotion to individualism: "Do your own thing." "I did it my way." "You’ll have to decide that for yourself." "YOU made your bed, now lie in it." "If you don’t look out for yourself, no one else will." "Look out for number one." Closely associated with the value they place on individualism is the importance Americans assign to privacy. Americans assume that people need some time to themselves or some time alone to think about things or recover their spent psychological energy. Americans have great difficulty understanding foreigners who always want to be with another person who dislike being alone. Americans assume that people will have their private thoughts that might never be shared with anyone. Doctors, lawyers, psychologists, and others have rules governing confidentiality that are intended to prevent information about their clients’ personal situations from becoming known to others. Americans’ attitude about privacy can be hard for foreigners to understand. Americans’ houses, yards and even offices can seem open and inviting. Yet in the minds of Americans, there are boundaries that other people are simply not supposed to cross. When those boundaries are crossed, an American’s body will visibly stiffen and his manner will become cool and aloof.