The induction of an experimental dream depends upon the existence of a certain ego control of dreaming and the possibility of this control being taken over by another individual. Some experiments were conducted on a group of patients in analysis and on normal individuals with the aim of investigating the transference meaning of giving suggestions. The patients reacted by producing dreams which expressed pregnancy and childbirth wishes in pregenital terms.

Suggestions are accepted or rejected in relation to the degree of anxiety or gratification activated by certain incorporative or expulsive phantasies. The suggestion is accepted if it is unconsciously equated with a 'good' substance and rejected when equated with a 'bad' substance. Similar mechanisms may be operative when suggestions are accepted or rejected by normal subjects in non-therapeutic situations. Suggestibility is probably associated with a regression from the reality ego to the pleasure ego.