The term collective unconscious comes from Carl Jung, the images and archetypes in the unconscious mind that are shared by all members of a species, including mankind. The term is still used by psychologists, and in esoteric New Age teachings.
The theory implies that there is a non-physical repository of our unconscious desires and memories for all of humanity. It is a good model for explaining dreams and other phenomena that can be hard to account for – but the theory remains unproven.
It is really hard to prove that a collective unconscious exists using any known current scientific means. Does the human race have a collective unconscious? Many esoteric teachings state that there is a non-corporeal consciousness surrounding the planet, supporting all forms of life on this planet. It is a good model and could explain a great deal. It would be the akashic record repository for the history of life on this planet. We have yet to establish any scientific basis for its existence.