Basic Concept Explained -- Ego

The Ego is the part of personality that is aware of the reality and is in contact with the external world.  It is the only constituent that takes the possible consequences of an action into consideration before doing it.  It operates on reality principle based on which the Ego attempts to satisfy the Id's impulses in an appropriate and socially acceptable manner.  Instead of constructing fantasies and hallucinating mental images, the Ego finds the appropriate objects in the external world to serve Id by realistically meeting its demands.  In order to do so, the Ego may suspend or redirect the Id's wishes, i.e postpones the discharge of psychic energy, in accordance with the demands of the reality. 

Example:
I am now at work having a class with my students.  The class lasts 2 hours and it has just started.  I am extremely hungry as I didn't have my breakfast this morning.  My stomach is rumbling like thunders and my Id urges me to grab something to eat immediately.  Yet, in negotiation with the Id and the Superego, my Ego, finally compromises that I have to wait until the end of the class.

The Ego employs secondary processes which include the cognitive and perceptional skills that help an individual distinguish between fact and fantasy and mediate between the demands of the Id and the Superego through channeling the libido (psychic energy) through socially accepted means, such as:
-  higher intellectual functions of problem solving
-  skills in reality testing
-  ability to marshal defenses to deal with impulses
-  self-control
- capacity of adjustment and adaptation. 

Though the Ego works as a loyal servant doing a hard job serving two masters, Id and Superego, it always ends up being harassed as the discrepancies between the two masters are always huge that cannot be easily bridged.  When this happens, the Ego may not be able to implement its strategies to resolve the inner conflicts and maintain a healthy or normal psychic equilibrium, and mental illnesses may then emerge.

References

Barlow, D. H., & Durand, V. M. (1999). Abnormal psychology :An integrative approach (2nd ed.). Pacific Grove: Brooks/Cole Pub.

Engler, B. (2009). Personality theories :An introduction (8th ed.). Belmont, CA: Wadsworth/Cengage Learning.

Gabbard, G. O. (2010). Long-term psychodynamic psychotherapy :A basic text (2nd ed.). Washington, D.C.: American Psychiatric Pub.