Extroverts tend to be adrenaline junkies who seek stimulation and live for fun! (overgeneralization). While introverts seek pleasure in more tranquil activities and may enjoy their own company more so. Why is this!?
Talking about biology in-depth may sound boring at first but hear me out!
It’s been found that extroverts have lower cortical arousal (Hans Eysenck). Cortical levels are regulated by the Ascending Reticular Activating System (ARAS) in the brain stem. What does this mean? We can hypothesis that if an individual has lower cortical arousal they therefore seek higher stimulation in order to raise it. Whereas those with already high cortical levels don’t need the extra stimulation as it’s already at a high level.
For you visual learners out there, imagine a set of scales that is off-balance (due to the cortical levels) and in order to balance it, high stimulation is either needed or not.
This explains why extroverts are sensation-seekers! They are on the radar for ways that will increase their cortical arousal such as partying, being with large groups of friends, high-risk sports etc. Introverts don’t need to engage in highly stimulating behaviours as their levels are high enough. They therefore typically get more joy out of reading, being with a couple of friends and having a cosy night in.
It’s fascinating to think from this approach that some of our behaviours are not up to the free will of our minds, but the biology and chemicals within our body.
Of course this is highly deterministic to state humans as so predictable. I believe this isn’t the sole cause of our behaviour, but it’s obviously a factor – a very fascinating one.
To make you think – It’s even been found that criminals tend to have low cortical arousal, such as in the case of extroverts…