Why americans seem more extroverted?

Question

We have alot americans on my campus and in class they seem so much more extroverted and confident,esp in speaking or performing infront of people they are very extroverted? why? I noticed this when I lived in the US too.

Answer 1

 they have to fill their emptiness in some way.

Answer 2

They are raised to believe that they are the supreme race in the world.

Sometimes I go out and I hear americans talking SO LOUDLY, like everyone has to hear it.