Does Your Birth Order Really Determine Your Personality Type?

Over the years, there has been a lot of research into understanding the development of personality types among siblings and how birth order might be an influence. While there is certainly indication that birth order is a factor in personality development, it is not the only one of importance.

Less than 50 percent of people fit the mold for birth order

It is not uncommon to find people that do not display the typical personality traits usually attributed to someone of their birth order. According to the findings of the White-Campbell Psychological Birth Order Inventory (PBOI), only 15 percent of men and 23 percent of women matched up to their birth order personality expectations.

Other considerations to factor into the equation

Since there are other factors that determine personality, there is no time like the present to take a look at a few of them:


It turns out that genetics truly has the most significant impact on the development of personality. Just as genetics is responsible for traits like height and hair color, it is also believed to predispose people to certain temperamental traits as well.

Research by Dr. Nathan Fox, distinguished university professor and lab director of the University of Maryland Child Development Lab, found a link between brain wave activity in infants and temperament. When Dr. Fox and his team mapped the brain wave activity of toddlers and infants, they were able to determine what temperament the child would develop later on.

The findings showed that babies who would develop a fussy and fidgety temperament had distinctive patterns in brain waves found in the right half of the brain.

According to Dr. Fox, “These infants are more likely to be fearful, intimidated and, in later life, shy and timid. What we are saying is that when it comes to personality, we do not start with a blank slate.”

birth orderGender

Gender differences among siblings can definitely play a role in personality development that may run contrary to birth order. According to Alan E. Stewart, Ph.D., a researcher at the University of Georgia, “Gender is a significant influence when it comes to the birth role that one develops within the family.”

As Dr. Stewart explains, when the first and second born children are of different genders, there is less pressure on the second child to establish an identity. They are fundamentally different already, thanks to gender. In this way, gender can blur the effect of birth order impact on personality development.

“When the first two children are different genders, they often both behave like firstborns,” says Kevin Leman, Ph.D., a psychologist and the author of The Birth Order Book.

Physical size

It is not surprising, given the known effects of bullying on children, that a sibling who is taller or more robust may be assertive over others. Age can also be a factor since older siblings are likely to outsize the younger ones in most cases, though not always.

Number of years between siblings

When there are large gaps of five years or more between the birth of siblings, it can break the chain of birth order. So a much younger child may take on the role of a firstborn if his or her siblings are more than five years older. The age gap definitely changes the typical interplay of closer siblings.

As explained by Frank J. Sulloway, Ph.D., author of Born to Rebel, “If you’re a second child whose sibling is 10 years older, then in most practical ways you grew up as a firstborn or only child.”

Do you have siblings? How do you feel about your personality in regards to your birth order?

—The Alternative Daily


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