Some lie to seem what they are not, others lie to hide what in fact they are. Many lie as defense mechanism. Sigmund Freud (1856? 1939), in its vast work on psychoanalysis explained the defense mechanisms, that are: it stresses it, negation, projection, reactive formation, identification with the aggressor and displacement against self. These mechanisms of defense are always in alert in the human beings, consequentemente to inhibit suffering and anxiety impulses. Some people, to protect themselves of an anxiety exaggerate in the defense to the point of if to stress (to exclude an impulse or feeling) stresses, it can be understood as a repressora action of a desire or impulse.

This repression if to give ahead of an episode that is processed and understood as dangerous. This episode it can be previous and exterior to the processing it stresses of it. Another form of defense would be the negation that is the attempt not to accept some fact as it is, and such fantasiar is the indicated way more for the negation. The defense mechanisms do not limit stress it and negation, also have the projection that it is the act to attribute in the other what is contained in I, that is, the individual confers to the other the qualities, feelings or intentions that are in its I. Already the reactive formation as defense mechanism is the feeling inversion or behaviors, for example, when the desire is confused with fear. The identification with the aggressor is in turn a defense mechanism where the individual fancy in itself what it cause anxiety. finally, the displacement against self that it is the displacement of a considered pulso disapproved for accepted considered other socially. If to observe the act to lie we will understand that the liar is a being stressed for is restraining itself exactly ahead of the reality that the fence and that not condiz with its will or the reality that it would like that he existed.