People may differ among each other in terms of introversion and extraversion. Introverts like to keep to themselves; they are self-involved, restraint, and at times highly sensitive. They have a tendency to turn inwards and explore their feelings and experiences. Extraverts, on the other hand, are energetic, enthusiastic, and impulsive. They are more externally oriented.
A major way in which individuals differ in terms of introversion and extraversion is their biological structure. Introverts have high brain activity, which makes them highly aroused, especially in socially stimulating situations. In contrast, extraverts have low level brain activity, which gives them a high threshold for stimulation and effortful in being aroused.
This level of brain arousal plays an important role in the activities of introverts and extraverts, including the nature of their interpersonal interactions. Introverts, being easily aroused, can find it discomforting to be in highly socially stimulating situations for too much of time. This is why they prefer to keep to themselves or have few interpersonal interactions.
It is not that introverts do not like to interact with others; they just find too much of interactions to be draining out their energy. This is why even when introverts do interact with people, they prefer to have few meaningful interactions that involve deep conversations rather than having a shallow talk.
In contrast, extraverts, due to having a low level brain arousal, always have the need to be stimulated. This leads to them to being highly energetic and wanting to be out with a lot of people. Unlike introverts, they always like to interact in groups. For them, being alone is not stimulating enough, which is why they require to be with a group of friends or associates.
As mentioned above, introverts not interacting with many people does always not mean that they do not like it. They get mentally and physically drained out, and due to this, at times they prefer to avoid social interactions. This does not also mean that they lack in social or interpersonal skills. Being involved in interpersonal interactions is more of a choice for introverts, rather than a lack in any kind of skills.
Introverts, in fact, can be very adept in social and interpersonal skills. A major aspect of any kind of interpersonal interaction is empathy. Research suggests that introverts are highly empathic. Introverts, due to their physiological structure, are more introspective, which makes them more self-aware. Being self-aware makes them more comfortable within themselves, which in turn, makes them more observant and thus, more conscious of others’ needs.
The high brain arousal of introverts also makes them very sensitive. They can easily pick up subtle cues from their surroundings such as slight changes in mood, emotional reactions, or body posture, of others. They use these subtle cues and react accordingly in interpersonal interactions.
There can, however, be a downside to this high sensitivity. Introverts, due to being highly sensitive, often get easily hurt by others. This becomes a deterrent for them to be involved in future interactions. An inherent discomfort in social situations coupled with a possibility of being hurt and embarrassed, increases the likelihood of avoiding being in too many interactions.
It is largely due to this that introverts prefer to interact only with few people. They like to spend more time with likeminded people, with whom they can talk on topics that they are interested in, and with who they can be themselves. This is why, even though they may prefer to interact with few people, their interactions are deep and their relationships are more long lasting.
If introverts are drained out by having too many interactions, extraverts derive their energy levels from these interactions. They, in a way, thrive on having many interpersonal interactions.
For extraverts, more than deep interactions, varied interactions become important. They feel like being with many people, and being excited and enthusiastic comes easily to them. This tends to make them more likeable among others as they can easily create a fun-filled environment and be entertaining for others.  
Being able to interact with many people enables them to have a large social network, giving them an increased sense of social support that turns out to be very comforting for them.
Extraverts being highly energetic around people are quite the opposite of what introverts can be. Introverts are highly restrained in their body language and expressions. When meeting people, even though they may be excited and really happy, they might just give a simple smile. This can be interpreted as not being interested or a lack of enthusiasm, but it is actually not the case.
Such instances prove to be advantageous for extraverts as they are very expressive and can easily reflect enthusiasm and excitement. They are not at all restrained in their emotional expression, which works very well for them in terms of interpersonal interactions. However, this unrestrained emotional expression can be a problem for shy extraverts.
There is a myth that extraverts are always bold and cannot be shy. Shyness is a temperament, which is associated with the amygdala – the brain area responsible for the fight and flight responses, and also known as the seat of emotions. A sensitive amygdala interprets regular situations, including normal social interactions, as fearful and anxiety arousing, causing the person to avoid it.
An extravert, that is, a person with low brain arousal leading him/her to be outgoing and seeking out social interactions, but at the same time having a sensitive amygdala that makes him/her avoid social situations, can turn out to be very problematic. Shy extraverts, thus, can face difficulties when it comes to interpersonal interactions. Over the years, they need to somehow learn to strike a balance between the two contradictions.

On the whole, individual differences with respect to introversion and extraversion have a strong influence on the nature of interpersonal interactions. Both introverts and extraverts like to interact with people, and find it beneficial, but they have their own ways of having such interactions.

Saif Farooqi

A PhD in Psychology (from the University of Delhi). I have been blogging about psychological issues for more than ten years. I am extremely passionate about teaching psychology. I'm a writer, podcaster, and TEDx speaker. I also conduct workshops and awareness programs in schools and colleges. Currently, I'm also working as an Assistant Professor at the Department of Psychology, Faculty of Social Sciences, Jamia Millia Islamia, New Delhi, India


TF said...

very nice article. i could especially relate to the sentence "can easily pick up subtle cues from their surroundings".

Saif Farooqi said...

Yeah, I believe every introvert will relate to that :)