The concept of the collective unconscious was introduced by the psychologist Carl Jung. It refers to a part of the unconscious mind that is shared among all humans, containing memories, experiences, and symbols that are universal across cultures. This means that certain themes, like myths and archetypes, can be found in stories and beliefs around the world, even if people have never met. The collective unconscious influences our thoughts and behaviors without us realizing it. For example, when we dream, we might encounter symbols like the hero or the mother, which are part of this shared unconscious. These symbols help us connect with others and understand our place in the world.