Freudian theory:

_ The idea that much of human behaviour stems from a fundamental conflict between a person's desire to gratify his/her physical needs and the necessity to function as a responsible member of society.

_ The struggle is bear out in three internal systems:

- Id (immediate gratification and directing a person's psychic energy towards pleasurable acts without regard to the consequences).

- Superego (the person's ethics working to prevent the id seeking selfish gratification).

- Ego (mediating among the other two).