Why Over-Thinking?

Speculations on the Evolution of Neuroticism

Why the Five Factors? Why is it that all humans can be reduced, on a scale of 1-to-10, to these traits:

• Openness to New Experiences
• Conscientiousness
• Extraversion
• Agreeableness
• Neuroticism

One theory is that the factors are like Dungeons & Dragons character sheets, where you roll a dice for different traits to create unique and interesting roles for everybody. Diversity in roles strengthens the group. A squad with only archers would be vulnerable to close-range attacks, for example.

The first four traits seem to fit the role-theory. Having a group with a blend of curious and skeptical makes sense. When your tribe is filled with curious folks who run around the forest getting sick off eating raw mushrooms and berries, then it pays to be conservative, waiting for knowledge to trickle back to the tribe. When everybody disregards the advice of elders, it pays to be the only one who doesn’t.

But, what is the purpose of neuroticism? Of the five factors, neuroticism is the only one that is inherently costly in one direction. Neuroticism is associated with mental illness and unhappiness. Why would anybody want that?

Neuroticism is an arrow

When I describe the five-factor model at parties, I use the label “introspection” instead of neuroticism…