Erikson aligned himself with the psychodynamic perspective, but reached beyond the work of his peers by incorporating a social component into his explanation of human development across the lifespan. His 8-stage model explains development from infancy through old age. This model has generated an abundance of research and has secured his place in psychology's history. It is important the note the place of conflict and crisis in his model as those are key elements in a psychodynamic orientation.

In Erikson's eight-stage model of psychosocial development, children between the ages of five and twelve years are in the Industry vs. Inferiority stage, which is characterized by the drive to prove one's worth both by society's standards and one's own. If a child in this stage should learn that he or she had the worst performance in the class on an exam, then he or she would have failed to meet both his/her and the teacher's standards.

Companionate love occurs after a long period of partner union. It lacks the passion associated with the first 5-10 years of a relationship, by Sternberg's model. This is the difference between companionate love and consummate love, which includes passion, commitment and intimacy. 

Gottman's four horsemen all have to do with the quality of interactions, not the quantity. Traits like defensiveness and stonewalling act as strategies to create separation, and contempt and criticism in language are attacks on the other partner. While inconsistent communication is certainly not good, it does not fall into Gottman's categorization. 

Stranger anxiety begins around 7 months and lasts until 11 months. Of note, separation anxiety can set in between 12-15 months. At 1-6 months is too young to demonstrate these characteristics, so babies are typically comfortable with strangers during this time.

A child generally develops a sense of self as a male or a female at 3 years. During this time they are also expected to be potty trained (achieve bladder control), ride a tricycle, and use around 900 words. By 4 years, the child will start to engage in play with other children and start role playing (ex. playing house). 

The response of an organism to stress is known as adaptation; this is the adjustment of an organism to a change in internal or external conditions or circumstances, i.e.stress.

Anxiety is an uneasy feeling of discomfort or dread, the source of which is often unknown to the individual. It is distress caused by fear. Adjustment is the action of bringing a body part into alignment with the others. This is also referred to as manipulation. Assimilation is the absorption of newly perceived information into the person's existing conscious structure. Accommodation is the adjustment of the lens of the eye to focus on images at various distances.