Introvert/Extrovert Evolutionary Theory


Graphic from

This morning I had a thought as to why the current world as it is would be skewed in favour of the extroverted. Supposedly, though some people claim it’s 50/50, the world is about 75% extroverts, and 25% introverts.

For this theory, I’m going on the basis of defining extroverts and introverts by the primary method by which people obtain their energy. Extroverts gain energy through social interaction; introverts gain energy though taking time away from people.

There are two possibilities that I can see as to why evolution would tend to favour extroverts. First, as humans started becoming more social (for protection from predators) those who gained energy by being part of an expanded social circle had the benefit of a positive feedback cycle. The more time they spent with the group, the more energy provided to them. In contrast, introverts would have stayed with the group for protection, but if they needed “time alone” and actually took it in the literal sense, this would expose them to more danger.

The second possibility has occurred to me now as I have a newborn. While child-rearing may be tiring no matter where you sit on the ‘vert spectrum, extroverts may be more likely to receive energy through interaction with their child(ren). In a survival situation where energy premiums are important, having a little bit extra energy may have been the difference between survival of the individual. Of course, if the individual does not survive, then in a predatory situation the offspring may not either. This isn’t to say that introverts are somehow “less” when it comes to their interactions with children – just that with extroverts, the slight advantage that they might gain with additional energy could have provided the additional push to skew in their favour in addition to the first point above.