“In a given individual, a certain set of behaviour patterns corresponds to one state of mind, while another set is related to a different psychic attitude, often inconsistent with the first. These changes and differences give rise to the idea of ego states. In technical language, an ego state may be described phenome-nologically as a coherent system of feelings, and operationally as a set of coherent behaviour patterns. In more practical terms, it is a system of feelings accompanied by a related set of behaviour patterns.”
Excerpt From: Berne, Eric. “Games People Play: The Psychology of Human Relationships.”