Beliefs about birth rank and it's contribution, personality, family role, and peer influence have been studied greatly by man psychologists and sociologists. The ideas about birth rank can reflect a different image of reality for siblings and parents. Birth orders can effect attributes of oneself's personality because of the constraints they may feel from another sibling. In contrast to multi-child families single-child families have their own statistics about how only children develop in regards to personality, family, occupation and peers roles. Though some may feel it yields drastically different, many studies have found that it only slightly differs.
The Identification of Birth Order Personality Attributes, views the first born child as the favored birth position followed by the middle, youngest, and only-child positions. The author Lawrence Nyman found that subjects ranked their own birth position similar to ways other s ranked that position.
Nyman took 139 undergraduate and graduate students and asked them to list three words that describe each birth position, first-born, middle born, last born, and only children. The subjects then had to rate each word they used in terms of positive or negative using a scale ranging from -5, being most negative, to +5, being most positive. The subjects were grouped according to their birth rank and sex. The favored position, started with first-born middle, youngest, and then only-child positions. Characteristics that some peoples found positive were considered negative by others. This contrast reflects the complications of personal dynamics.
The eldest birth position was viewed as dominant-aggressive, a quality that reflects both strength and weakness. The middle birth position identified with social able characteristics, thoughtfulness, responsibility, ambition, and independence. The youngest birth position was viewed as social and thoughtful.