ABSTRACT
This chapter begins with a brief section describing the social and historical context in which American only children have been placed during the 20th century. I believe that understanding this context is necessary in order to evaluate the psychological literature about only children. This literature has a relatively long tradition within psychology, beginning with early birth order studies (e.g., Ellis, 1904) and continuing to the present. The major part of this chapter reviews the psychological literature about only children. This review is organized into the five topics about only children that have received continued attention from psychologists: intelligence, achievement, interpersonal orientation, self-esteem, and marital success. Throughout this review, I have emphasized the contributions of parental characteristics and parent-child relationships in addition to the effect of a lack of siblings on the development of only children.
