The girl who is the social butterfly of the group and loves hanging out with people must be an extrovert, right? And the guy in the corner who is just observing the situation must be an introvert, or the woman who claims to not enjoy social events too much and rather stays at home.
If only extroversion and introversion were that simple. But they are not.
That is the trap most people fall into: Mistaking sociability with extroversion.
The truth is, true extroversion and introversion are about the main way you interact with the outer or the inner world.
You can be primarily focused on the outside world, but at the same time avoid social events and prefer hanging out with a significant other at home. Or on the other hand, you can be primarily focused on your internal world of feelings, or imagination, but be interested in social belonging and politics.
In short, you can be an asocial extrovert or a sociable introvert.
You may ask then, what truly determines someone’s degree of sociability, if not their degree of extroversion or introversion?
The degree of sociability boils down to your instinctual stacking, which is a fancy term that describes the order of which you value the three universal instincts from the most to the least: Social, Sexual, Self-preservation.
The most sociable (stereotypically “extroverted”) instinctual stackings are those who have the Social instinct as their first: So/Sx and So/Sp.
The least sociable (stereotypically “introverted”) ones are those who have the Social instinct as their last: Sp/Sx and Sx/Sp.
The most on/off with their sociability (stereotypically “ambiverted”) are those who have the Social instinct as their second: Sp/So and Sx/So.
Personally, as an So/Sx who’s a true introvert (IEI-Ni), I desire and feel more fulfilled by social interactions, but I can easily get drained by them. That’s why I often try to mostly get my “social fix” through online interactions, because those drain me way less, but they are also less fulfilling than those IRL.
Another example would be the many extroverted (SLE and ILE) men I have come across who would claim they used to be “introverted” when they were younger: as in, scared of social situations, suffering from social anxiety. Once they overcame their anxieties concerning social interactions, they suddenly emerged to be extroverted, “sociable” guys. Those guys were all Sx/Sp. It was the SO blind spot that made them feel like they were “introverted”. They misconstrued shyness and social disinterest or anxiety as genuine introversion, which is a common mistake even Typology fans make. Often do I hear someone say something along the lines of: “Are you sure introverts (e.g ILIs) can be Sx/So or So/Sp? Aren’t they/all introverts Sp/Sx?” Or on the other side of the coin, there is the trend of typing almost every Sx/So or Social first person as an extrovert by default: “He’s so sociable, he must be an extrovert”.
No, not all introverts are Sp/Sx, but the stereotypical introvert is.
No, not all extroverts are So/Sx or So/Sp, but the stereotypical extrovert is.
To determine someone’s true extroversion or introversion, you cannot rely on their instinctual stacking which only shows you how willing they are to be sociable, or how much they value the quality of being sociable in themselves and others.
Having said that, there are certain extroverts that will naturally be rather sociable regardless of their instinctual stacking: ExFx types, like SEE, ESE, IEE, and EIE. While the naturally least sociable ones are IxTx types, like LII, ILI, SLI, and LSI. Their degree of sociability is the least affected by their stacking or Socionics subtype. The factor here seems to be the strong grasp on Extroverted Feeling for the former types, or the lack of it for the latter. Whereas with the other types, their stacking, Tritype, or Socionics subtype can greatly influence how much they will come across as being sociable or not.
Note: The exception to the “SO-last people are the least sociable” rule are SEE, ESE, IEE, EIE as already mentioned, as well as Self-preservation Sixes, who in an attempt to feel more safe and secure often act more “sociable” than they truly are.