Should We Still Be Labelling People “Introverts” and “Extroverts”?

by Sophie Reeve-Foster

Hans Eysenck

Carl Jung’s first coined the terms introvert and extrovert in Switzerland in the 1920s. He proposed that introverts turn energy inwards, acknowledging more readily their internal psychological problems, while extroverts seek intensive contact with the outside world. No-one would be 100% of each, but somewhere on the spectrum, leaning often towards one end. An ambivert, though rare, would share equal quantities of each.

In the 1960s, Hans Eysenck’s added elements to the existing idea: suggesting that the characteristics’ main reason for their behaviour is the way in which they regain energy. Introverts “recharge” by being alone, after using it up socialising, while extroverts get their energy by bouncing off others. This, he said, was because introverts have a higher level of brain activity and feel a greater need to shield themselves from external stimuli. This means the trait of “shy” often characterised towards them would be a great oversimplification, and not realistic in most social interactions.

Extroverts would have an overall lower neural activity, so would feel the need to expose themselves more to external factors to be stimulated. He summarised that the two tendencies of measuring each were impulsiveness and sociability, both being more extroverted traits.

Further theories suggested that these two personality types use different brain areas to form thoughts generally. They implied the reason extroverts appear smart and full of ideas is because they use their short term memory and speak often, without always thinking carefully about what they’re going to say. This would make them good at conversations and skills like debate or confrontation. Introverts, instead, would use their long term memory to form thought, which would take time to retrieve and develop. Thus, they would prefer to take time to write an impactful letter or email.

Extremely popular tests such as 16 personalities to the Enneagram are based on the foundations of being an introvert or an extrovert, and it’s clear that they’re fun to do. The intense desire to fit in as humans drives a huge amount of what we do and how we behave, so categorising ourselves another way like this makes it easier for us to view others and perceive ourselves, whether it provides an explanation for actions or makes us feel less guilty about them. It also taps into our narcissistic side, which can definitely be a good thing as well as a bad thing.

But, is there any actual evidence for the existence of these personality types? Many of the ways of measuring them happen from self-report data which is highly unreliable, often tending towards social desirability or being altered by social comparison. In addition, the origins of these characteristics are very difficult to pinpoint.  

However, some twin studies have found a genetic component to the personality traits. Another test showed increased blood flow in areas of the brain dealing with internal processing and problem solving with introverts, in comparison with areas dealing with sensory and emotional experience for extroverts. Extroversion has also been linked to a more sensitive mesolimbic dopamine system to potential rewards, potentially explaining the high energy and reward they can radiate.

Once we hear a rule perceived to be true, it is surprising and in some cases worrying how easily we conform to believe and go along with it. One small piece of anecdotal evidence can be enough to sway our belief of a whole theory. Noting how often we ignore results we don’t like or agree with, is another way to measure the bias perception. Some less professional websites will tell quiz participants they are a certain personality type at random, with hope that one in 10 will fully agree and share the quiz around or trust the website from then onwards.

While it’s unclear as to whether the fixed terms apply to the human population, the basis of the concepts are easy to get on board with and relate to, and the implications in society can be extremely beneficial. Some modern workplaces have adapted their environments or meeting styles, and ways of dealing with clients in psychotherapy, for example, can change in response, which can only be a good thing.