Anal Stage  -  The second stage in Freud's developmental theory. During this period the child obtains pleasure through defecation, but this comes into conflict with toilet training. Children who do not adequately resolve this conflict become "anal retentive."

Ethology  -  The study of animal behavior in the natural environment.

Genital Stage  -  The final stage in Freud's development theory. During this period the adolescent focuses on obtaining pleasure through reproductive relationships with members of the opposite sex and a productive relationship with society as a whole.

Insecurely Attached  -  A category of attachment behavior created by Mary Ainsworth to describe the behavior of infants in her Strange-Situation Test. Insecurely attached infants become upset at the departure of the mother and are not comforted by the mother's return.

Latency Period  -  This period follows the phallic stage and precedes the genital stage in Freud's developmental theory.

Oral Stage  -  This is the first stage in Freud's developmental theory. During this period, the child obtains pleasure through the mouth from the mother's breast. A child who does not advance beyond this stage will display "oral fixations," e.g. cigarette smoking.

Phallic Stage  -  This is the third stage in Freud's developmental theory. During this period, the child becomes aware of his or her parents as sexual objects, which leads to repression of aggressive and sexual urges towards them and identification with either the mother or the father.

Securely Attached  -  A category of attachment behavior created by Mary Ainsworth to describe the behavior of infants in her Strange-Situation Test. Securely attached infants become upset at the departure of the mother but are easily comforted when she returns.