Sigmund Freud thought that what you do comes from the desire to seek pleasure and avoid pain. Most determinant in one's early years, conflicts coming from the "pleasure principal" last a lifetime.

For Freud, the mind is intimately linked to past experience (both conscious and unconscious). How much and what mental experience a person has repressed is key to evaluating how he/or she functions at present, along with behavioral effects caused by the admixture of sexual drive (libido) and aggression. Freudian psychoanalysis seeks out significant childhood events and their attendant fantasies, wishes, and dreams.

According to Sigmund Freud, personality develops through several stages:

1. Oral (birth to about age 1): this stage primarily involves an infant’s pleasure stimulus via his or her mouth; includes sucking, such as nursing, pacifiers, or finding his or her thumb for pleasure and comfort, chewing on toys, and spitting objects out of his or her mouth.

2.Anal (ages 1 to 3): the infant moves from oral pleasures to the elimination independence stage.The joys of toilet training are the way parents deal with the infant’s newly discovered freedom – expelling feces.

3. Phallic (ages 3 to 6): The child becomes aware of his or her own sexual identification, discovering pleasure when the genital area is stimulated. Freud felt a process of this stage was feelings of sexual bonding to the parent of the opposite sex. He categorized these as:

- The Oedipus Complex (castration anxiety) – Boys feeling sexually attracted to their mother and feeling competitive with father for her attentions.

- The Electra Complex (penis envy) – Girls feeling sexually attracted to their father and jealous of their father’s attentions for their mother.

4. Latency (ages 6 to 12): this is the stage where sexual desires are overshadowed by the child’s need to adapt to his or her environment. Tending to avoid relationships with the opposite sex, the child is drawn to authority figures (teachers and coaches at school, etc.), further developing his or her superego.

5. Genital (puberty and older): this stage is dominated by puberty, hormones kicking in and reigniting the adolescent’s sexual drives. He or she progresses from the selfish sexual pleasures of the phallic stage, turning his or her attentions toward others and discovering what love is on a more mature level.