Only 10 percent were middle class. - Tom Butler-Bowdon

The work of both Piaget and Kinsey suggests that while biology is always a dominant influence on behavior, environment is critical to its expression.

They may camouflage their true feelings in ingenious ways: To show that they are not vain, they may purposely pay less attention to dress or be overly modest.

The ego develops a defense in order to protect itself against being overcome by unconscious demands such as sex and aggression. The work of the psychoanalyst is to get the person to become conscious of their instinctual urges, which may involve isolating the pain experienced when they were originally confronted by an unsatisfied impulse.