Freud, the father of the psychoanalytic school, believed that we forget what threatens us. The threatening, shocking, painful, stressful, and ego- dissatisfying experiences are pushed back to the unconscious.
In other words, these experiences are repressed in the unconscious, and cannot be retrieved when needed. Hence, motivated forgetting is a case of retrieval failure.
Freud observed, “Forgetting in all cases is founded on a motive of displeasure.” We forget, because we like to forget. Repression is the key mechanism underlying forgetting.
In case of repression, there is no loss of retention but there is a strong inhibition to recall, and this inhibition causes the retrieval failure. Since such type of forgetting occurs because the subject intends to forget anxiety- provoking and ego-dissatisfying experiences, this is also called intentional or motivated forgetting.
The retrieval of the repressed memories is possible only under special circumstances using a few psychoanalytic techniques. These techniques are free association, hypnosis, and dream-analysis. This theory of forgetting explains why pleasant materials are better remembered than the unpleasant ones. The unpleasant materials are ego threatening, and therefore, may be repressed in the unconscious.
Our motivational needs not only prevent retrieval of certain memories but even change the tone and the content of the memories that we retrieve.