Introverts vs Extroverts

The terms introvert and extrovert were first devised by Carl Jung, a famous psychologist, in the 1920s. Both of these personality types occur on a spectrum which means nobody is completely one or the other. People lean towards either direction of the spectrum and in varying intensities, but can display characteristics of both types. Researchers estimate that 50%-74% of people are more extroverted, while the other 16%-50% tend to lean towards introversion.

Regardless of which type you lean towards, it's important to remember that people can change personalities over the course of a lifetime. Someone who was more introverted as a child, may find that they've become more extroverted as an adult. These fluctuations in the personality spectrum are completely normal. Some people even work to be more or less extroverted/introverted with help from a therapist or self-help program! So, what are the main differences and what causes people to lean one way or the other? Let's take a look.



Introverts naturally tend to be more introspective and focused on their internal thoughts, feelings and moods. They also tend to have personalities that are more quiet and reserved. For example, after spending time in a active social group setting, they'll often need to "recharge" by spending some time alone. The following are just a few of the signs of an introvert. 

1. Being around a lot of people drains their energy

2. They enjoy solitude

3. They have a small group of close friends

4. People often describe them as quiet or difficult to get to know

5. Too much stimulation leaves them feeling distracted and unfocused

6. They are very self-aware

7. They like to learn by watching

8. They are drawn to jobs that involve independence



Extroverts can be very outgoing, vibrant, and social. It's no wonder that they are often described as "the life of the party". Extroverts thrive off of social interactions and have a difficult time turning away attention if they are presented with an opportunity. Here are a few common characteristics of extroverts.

1. They don’t like or need a lot of alone time

2. They thrive around other people

3. They have many friends and acquaintances

4. They prefer to talk out problems or questions

5. They're outgoing and optimistic

6. They aren’t afraid of risk

7. They're flexible

8. They prefer social and group settings

The Science

In order to know why some people are introverted and some people are extroverted, it is important to understand the role of our body's physiology. The way that our bodies respond to the outside environment plays a critical part in determining the level of extroversion and introversion in each of us.

On a physiological level, neurons located in the brainstem known as the reticular activating system (RAS) are responsible for regulating levels of wakefulness in the body. The RAS also plays a part in controlling how much information our bodies process while awake. When we are confronted by potential threats in an environment, the RAS increases our arousal levels in order to help us avoid danger. 

One psychologist, Hans Eysenck, suggested that these arousal levels could play a part in which side of the spectrum we lean towards. According to Eysenck's theory, introverts are those that have naturally high levels of arousal which causes them to avoid activities that lead to overstimulation. Whereas, extroverts naturally have lower levels which causes them to seek environments where they can become stimulated.