Freud believes that behaviour was due to psychological factors rather than behavioural factors, which were largely influence by the unconscious part of the brain. He used a metaphor of an ice berg, the tip is the conscious mind, underneath, the larger part is the unconscious mind. Most of our everyday actions are from the unconscious, which reveals themselves in slips of the tongue (Freudian slips). Freud believes that it protects us from traumatic memories and uses defence mechanisms to prevent the person becoming aware of them.