Why would an extraversion spectrum evolve?

[rousseau]

Read through Susan Cain's Quiet last night which had a passage that might work:

Introverts are introspective, reflective, careful and deliberate, which has it's advantages in reproduction. Extroverts are gregarious, and sexually rambunctious which also has it's advantages in reproduction.

But those who are in the exact centre of this spectrum: introspective, careful, deliberate AND gregarious are going to be the most successful. So what we see is phenotypic variation producing outliers while the middle of the spectrum stays more or less constant, and the vast majority of people fall closer to the centre than the fringes.

In other words to be a strong introvert or a strong extrovert is to be somewhat maladaptive.

 

[rousseau]

My sister said my nephew had grown introverted. What brought him out of it was participation in karate.

Behavior modification works, maybe not always. You can pay for fear of flying treatments. You are gradually led up to flights.

Some people are terrified of heights or leaving their home.

Might want to read Susan Cain's Quiet.

The extraversion spectrum doesn't work that way. What your nephew learned was confidence / social skills, which isn't the same thing as 'growing extroverted'. Where you are on the spectrum is fixed, but your social skills aren't.

That extraversion spectrum measures your propensity to feel stimulated from situation to situation. Introverts like quieter music, extroverts like louder music, for example. This means that in overly exciting situations introverts get overwhelmed, while extroverts want more.

The only connection to social skills is that because introverts seek out solitude more often they often get less practice than extroverts, but it's not abnormal for introverts to be good at socializing.

My wife and I are perfect examples. She's more extroverted than I am, but I'm far more confident socially than she is. Still in social situations she can sit there all day talking to people, while I get worn out.