It was Carl Jung who coined the terms introvert and extrovert in the 1920s to describe contrasting personality types and to explain why different people were energised in different ways. He hypothesised that extroverts gain their energy from their social interactions and external environments and that they tend to feel uncomfortable and anxious when they find themselves alone.
Introverts, on the other hand, are able to replenish their energy levels when they are in quiet environments. Unlike extroverts, they find socialising and busy environments over-stimulating and too demanding.
Introversion and extroversion are at the opposite ends of the same spectrum. No‑one is completely one way or the other and everybody moves up and down the spectrum depending on external and internal factors. However, most people tend to display more characteristics of one of these personality types over the other.
It's nearly a hundred years since Carl Jung first made his observations and in this time science has proved that there are indeed physical differences in the brains of introverts and extroverts that explain the differences in personality.
Perhaps the most fascinating difference is in the way that introverts and extroverts process information. In other words, there are differences in the way they think. When information from the external world is received by an extrovert's brain it travels via a short pathway that goes through the areas of the brain where touch, taste, sound and sight are processed.
However, when an introvert receives stimulus from the outside world the pathway that the information travels is a lot longer. The information goes through many areas of the brain including:
- the right front insular - an area involved with empathy, emotional thought and self‑reflection,
- Broca's area - the area that activates self-talk and plans speech,
- the right and left front lobes - which plan and select ideas and actions, and
- the left hippocampus - that decides what things are personal and places them in long-term memories.
This long journey that the information takes when an introvert receives stimulus from the external world is the reason why introverts take longer to speak, react and make decisions.
But that's not all! Scientists have discovered that introverts have larger, thicker grey matter in their prefrontal cortex. The prefrontal cortex at the front of the brain is linked to abstract thought and decision-making. Extroverts, on the other hand, have thinner grey matter in the same area.
What does this mean? It means that while extroverts have the propensity to live in the moment introverts devote more of their energy and resources to abstract thought. So, if you need instant answers and immediate action, ask an extrovert but if a solution requires deep thought and creativity seek out those introverts in your life.
