Electra complex classical psychoanalytic theory, the child's identification with the same-sex parent is the successful resolution of the Electra complex and of the Oedipus complex; his and her key psychological experience to developing a mature sexual role and identity. Sigmund Freud instead proposed that girls and boys resolved their complexes differently—she via penis envy, he via castration anxiety; and that unsuccessful resolutions might lead to neurosis. Hence, women and men who are fixated in the Electra and Oedipal stages of their psychosexual development might be considered "father-fixated" and "mother-fixated". As a psychoanalytic term for daughter–mother psychosexual conflict, the Electra complex derives from
Oedipus and the Sphinx pass. Failure means his own death and that of the besieged Thebans. The riddle was: "What walks on four feet in the morning, two in the afternoon and three at night?". Oedipus answered: "Man: as an infant, he crawls on all fours; as an adult, he walks on two legs and; in old age, he uses a walking stick". Oedipus was the first to answer the riddle correctly and, having heard Oedipus' answer, the Sphinx was astounded and inexplicably killed herself by throwing herself into the sea. Oedipus thereby won the freedom of the Thebans, the kingdom of that city