According to the Swiss psychiatrist Carl Jung, the collective unconscious (also known as the collective subconscious) is a part of the unconscious mind common to all humans, a “reservoir of the experiences of our species.” The collective unconscious is characterized by archetypes, original models of people, objects, or concepts.
Example: A popular archetype which appears independently in the stories of many different cultures is that of the wicked fairy-tale stepmother.
This website provides a fabulous diagram of Jung’s theory along with a detailed description: http://www.kheper.net/topics/Jung/collective_unconscious.html
Fournier, G. (2010). Collective Unconscious. Psych Central. Retrieved on September 1, 2015, from http://psychcentral.com/encyclopedia/2008/collective-unconscious/