Relationship Between Birth Order and Personality Traits: A Review Study

The present paper systematically reviews the effect of birth order on personality traits focusing mainly upon the traits of introversion and extroversion. Early work by Alfred Adler and Frank Sulloway’s Born to Rebel theory, along with the Resource Dilution Model, offer different insights into how being a firstborn, middle child, youngest, or only child could shape a person’s traits. Firstborns, for example, are often seen as responsible and mature, which might make them lean toward introversion or extroversion depending on how much attention and responsibility they receive from parents. Middle children, on the other hand, tend to develop strong social skills and flexibility, which could encourage extroversion. Youngest children are frequently described as more outgoing and adventurous, perhaps due to lessened parental pressure. Only children show a range of traits, shaped largely by their relationship with their parents and peers. However, research on this topic is not without its challenges. Many studies rely on self-reported data, which can be biased, and external factors may complicate the results. While the existing research suggests that birth order might have some influence on personality, the connection is far from straightforward. It appears that factors like heredity, parental behavior, social environment and individual experiences play a larger role. The review concludes that more longitudinal studies are needed to fully understand how birth order affects personality development as the current findings are contradictory, complex and indicate towards thorough and innovative researches in future.