short definition of Id, Ego and Superego: Explained simply, the Id, Ego and Superego are three parts of the human psyche which make up who we are, according to Sigmund Freud . The Id is the primal animalistic part in us who only listens to his desires. The superego is our conscience telling us some things are right and some are wrong. The Ego is the part caught in the middle, is the part that has to negotiate demands from the Id, the Superego and reality.
Further explanations on Id, Ego and Superego:
For Freud, the three mental faculties of Id, Ego and Superego are also three stages of mental development. We are born pure Id, knowing only the will to satisfy our desires and needs. The Id according to Freud operates under the "Pleasure Principle" that wants maximum enjoyment and minimum pain.
As we grow we slowly come to see that reality imposes certain restrictions on our pleasure principle (basically, we realize that we can't have or do anything we want). We therefore develop an inner agency called to Ego which is in charge or mediating desires coming from the Id and demands posed by reality.
As the ego comes in contact with reality he encounters values and beliefs that originate from the world around him (say education for example). These external values are internalized in order to form the Superego which acts as a voice demanding to do "the right thing".
It is important to note that or Freud, the Ego is who we experience ourselves as. The Id and Superego are both "blind" in being out of touch we actual reality. This is why both the Id and Superego pose impossible demands from the Ego which is in a way "caught in the crossfire" between animalistic urges and cultural restraints.