Unraveling the Complexities of Family Dynamics

For over a century, the question of whether birth order influences personality has fascinated scientists and the general public alike. Despite numerous studies, the answer remains elusive, and researchers are now suggesting that the relationship between the two may be more complex than previously thought.

Rodica Damian, an associate professor of psychology at the University of Houston, explains that previous studies have often included small sample sizes and relied on self-reported personality tests, which may be susceptible to bias. “The Big Five” personality traits, which include extraversion, agreeableness, conscientiousness, neuroticism, and openness to experience, have been commonly used to measure personality in birth order research.

However, recent studies have pointed out that a number of confounding variables can make it difficult to investigate whether birth order has a systematic effect on personality. For example, family size and socioeconomic status can play a significant role in shaping a child’s experience and personality. Damian notes that in families with more children, levels of intellectual stimulation may decrease, while in families with fewer children, older siblings may be more likely to take on a caregiving role.

Despite these challenges, researchers have made some interesting discoveries. For instance, a study by Julia Rohrer and her colleagues found that birth order does not have a lasting effect on broad personality traits, but it does seem to influence intelligence. Firstborns tend to score higher on intelligence tests, and this effect is also seen in self-reported intellect.

However, Rohrer cautions that these findings should not be taken as evidence of a universal pattern. “It’s not that every eldest daughter is responsible and caring, but for some women, this experience may have shaped their personality,” she explains.

In fact, Rohrer’s study found that birth order can have a significant impact on outcomes in certain cultural contexts. For example, in the UK, the concept of primogeniture, where the eldest child inherits family wealth and titles, can influence a child’s experience and personality.

Age-related experiences can also be mistaken for personality traits influenced by birth order. Damian notes that older siblings tend to be more responsible and self-controlled, not because of their birth order, but because of their age. Similarly, younger siblings may appear more sociable and less neurotic, not because of their birth order, but because of their age-related experiences.

In terms of intelligence, Damian suggests that the link between birth order and intelligence may be due to cognitive stimulation in the early years of life. In families with more children, levels of intellectual stimulation may decrease, while in families with fewer children, older siblings may be more likely to engage in activities that stimulate their cognitive development.

The relationship between birth order and personality is further complicated by the fact that only children are often excluded from studies on birth order. However, a recent study by Michael Ashton and Kibeom Lee found that middle-born and last-born siblings averaged higher on the “Honesty-Humility” and “Agreeableness” scales than first-born siblings.