No theory forbids me to say "Ah!" or "Ugh!", but it forbids me the bogus theorization of my "Ah!" and "Ugh!" - the value judgments. - Theodor Julius Geiger (1960)

Personality Tests are like Horoscopes

Horoscopes, personality tests and the illusion of self-knowledge

Astrology, DiSC, Myers-Briggs – they tempt us with the lure of self-discovery. The positive descriptions we assign to ourselves feed our ego. But do they really reflect who we are, or are they just part of a psychological illusion we fall into?

Ever since I was a kid, I've been skeptical of the idea of horoscopes: celestial bodies that dictate our personalities, really?

When I started working, I was quickly introduced to many (I remember at least four different) types of personality tests, used both individually and in teams. They often reminded me of horoscopes..

P.T. Barnum – also known as The Greatest Showman – was very adept at using the power of suggestion. He operated a freak show that he called "The Greatest Show on Earth." His favorite saying was, “A sucker is born every minute.” The Barnum Effect that bears his name is about our tendency to accept vague and general descriptions as uniquely tailored to us. Horoscopes and personality tests take advantage of this effect and provide general statements that we unconsciously associate with ourselves, reinforcing the illusion of self-awareness.

The science behind it

Although certain personality traits exist (think introversion/extraversion), they are normally distributed. Personality types are more of a construct than a concrete thing. These categorizations oversimplify the complexities of human behavior and fall into the same pitfalls as Barnum's showmanship: attractive, yet fundamentally flawed.

What this means for professionals

In the corporate world, personality tests may seem like quick fixes for understanding team dynamics or individual behavior. But like the illusions of Barnum's circus, they can lead to misjudgments and false attributions. Instead, the social sciences offer a nuanced understanding of behavior in diverse contexts. Local rationality and structural factors are important here.


Although astrology and personality tests provide a sense of comfort and connection, the reassurance they provide lasts only a very short time. The insights they provide are like the smoke and mirrors of a magic show.

Furthermore, as we now know about the existence of neurodiversity, we need an environment that values the uniqueness of individuals, without limiting them to predefined frameworks.