Let’s not fit people into boxes we create

We love to categorise ourselves and others into personality types. Maybe you’re a “Type A.” Or maybe the Meyers-Briggs Type Indicator, versions of which many have taken on Facebook, labels you a “Protector”. But how distinct are these types? Is everyone clearly Type A or Type B, with no one in between? Or do people fall on a spectrum? If there’s a spectrum, are there two clumps with a few people between, or one clump in the middle with a few people at the extremes? Or something else?

Decades of research have pointed to at least five independent personality traits: openness to new ideas, conscientiousness, extraversion, agreeableness, and neuroticism. You can be high or low on each. This is called the five-factor model of personality. Meanwhile, research on personality types — clusters of traits — has been more controversial. Some studies find three types, called “resilient,” “overcontrolled,” and “undercontrolled,” but others don’t. The study analysed a much larger dataset than previous studies — 1.5 million personality test scores, versus fewer than a thousand for most studies — in an attempt to resolve the matter.

The method highlighted four clusters, which researchers named: “average” (average on all five personality dimensions), “role model” (low on neuroticism, high on openness, conscientiousness, extroversion, and agreeableness), “selfcentered” (low on openness, conscientiousness, and agreeableness), and “reserved” (low on openness and neuroticism).

But how clustery are the four clusters? How archetypal are the types? In the population metaphor, are there dense cities surrounded by desert, or is it a land of homogenous suburbs with several barely denser neighbourhoods? The clusters exist in five dimensions, one for each trait, which is hard to visualise.

However, while seeking some intuition about the clumpiness of the personality types it is fair to say that they are definitely not well separated and there is no ratio of the density near the clumps to the density elsewhere. The major insight from the study is that there is not any robust signature about lumps at all. In the land of suburbs, those slightly denser areas are reliably slightly denser.

So although people love finding patterns in the world, typecast carefully. That means not assuming that if someone matches a type in some ways, he will in others. Let’s say someone seems low in openness and conscientiousness. You might assume he is also low in agreeableness because those three traits cluster together as the “selfcentered” type. But the chance that someone low in openness and conscientiousness is also low in agreeableness appears barely more probable than the chance that the person is high in agreeableness. Rather than suggesting that we categorise people, what this study reminds us is that people don’t always fit into the bins we expect.

Before you read the headlines about this study and say, “Oh, there are four personality types? Which one am I?” I’ll tell you: You’re not any of them