6 Science-Backed Signs You're An Older Brother

Growing up with siblings is both a blessing and a curse. Nobody knows you better than they do, but that also means nobody can make you laugh, fume and cry like they can.

Approximately 80 percent of Americans grow up with at least one sibling. And if you're the older brother, you know you're in a league of your own. Below are several science-backed signs you're the big bro, through and through.

1. You're protective.

No one messes with your kid brother or sister and gets away with it.

Being protective of your younger sibling comes with the territory of being an older brother -- and that can be a very good thing. A 2007 study published in the Journal of Child Psychology and Psychiatry  found that positive relationships between siblings had a protective effect and were an "important source of support" for families. In other words, the closer your relationship, the more supportive you are of one another.

2. You're a little intense.

Being an older brother often comes with high expectations. Eldest children have a tendency to be a little hard on themselves while putting an emphasis on traditional achievement .

The oldest sibling in a family is often seen as more accountable  and the one who is most likely to conform . A 2008 study found that parents are more strict with the oldest child, relying on them to be the responsible ones .

3. You're a leader.

Firstborn children often naturally assume a position of leadership  within a family, taking on the role of an authority figure  for their younger siblings.

What's more, recent research from Harvard Business school suggests that men are more eager for positions of power . Since older brothers fall into both of these categories, they are likely to become leaders in many areas of life.

4. You're kind of a genius.

Or, at the very least, a little smarter than your younger siblings. A 2007 study of 250,000 Norwegian young adults  found that firstborn men had an average IQ 2.3 points higher than their younger brothers.

"Every time you add a child, you’re diluting the intellectual environment of everyone in the family," the researchers wrote in the study’s conclusion.

Way to go, smarty.

5. You're probably the "successful" one.

Older brothers may have an advantage in both the academic and professional worlds. Oldest children statistically do better in school and are more likely to succeed in business .

And even if you aren't winning at life just yet, researchers have found that parents are more likely to perceive oldest children as successful. So when all else fails, at least your mom thinks you're great.

6. You have a big influence on your younger siblings.

Being an older brother comes with plenty of responsibility, especially when it comes to influencing the rest of your family.

For example, studies have shown that younger siblings are significantly more likely to smoke  if their older siblings have done so. However, this influence can also have a positive effect too. An older sibling's success has been shown to have a "spillover effect" for younger siblings, which can boost their performance.

Your parents may have raised you, but your siblings play a big part in shaping you . After all, for most of us, it's the longest relationship we'll have in life .