We will start with Sigmund’s Freud’s theory of psychosexual stages as it is the oldest and best known developmental stage theory. Moreover, it influenced later theories, particularly Erikson’s. Freud proposed five psychosexual stages: oral, anal, phallic, latency, and genital. Freud’s general theory of psychology (often referred to as his metapsychology) is difficult to understand in modern terms. He wrote in the late nineteenth and early twentieth century and framed his concepts in the physical science of the day. It was very important to him that his work was seen as having scientific merit.

From a modern vantage point, however, some of his theories seem like he was trying to fit a square peg into a round hole. Each stage of Freud’s theory refers to a part of the body known as an erogenous zone. This refers to the area of the body where libido (loosely translated as sensual pleasure) is most powerfully concentrated. Personality traits accompany each erogenous zone. For example, the anal stage is associated with either a rigid need for order or a messy lack of self-discipline. Later theorists interpreted his psychosexual stages less literally, seeing his ideas in more metaphorical terms. Erikson translated these ideas into social constructs.

The oral stage occurs during the first eighteen months of life. During this time the child’s primary erogenous zone is in the mouth. The personality traits associated with this stage include dependency and a kind of oceanic and all-encompassing emotional experience. When emotions are felt, they seem to take over the whole world. If we look at babies of this age, we can see why Freud called it the oral stage. For one thing, nursing is a central part of their life. Moreover, as any parent can tell you, babies love to put things in their mouth. Additionally, we expect dependency from children at this age. As they are incapable of surviving on their own, they have intense and continuous need of parental attention.