When it comes to socializing, people are usually split into two groups, extroverted and introverted. Extroversion is usually characterized by being outgoing and gaining energy from social events and sociability. On the other hand, introversion is characterized by quietness, as it takes a lot of energy to socialize than to be shy and reserved. When extroverts make up three-quarters of the America population, being an introvert can seem weird, but is normalized when it is explained that it is not that introverts dislike people or social interaction. It takes more energy for introverts than extroverts to engage in social interactions, and they can find entertainment in their thoughts not just other people.
The introvert wants to be as social as anyone else, but it comes harder to them or is less of a necessity. The stigma behind being an introvert has faded because of this explanation, but what if you actually do dislike social interactions, hanging around people and and rather be alone with your thoughts? You may be asocial.
Some view being asocial as a type of introversion as in an asocial introvert, but I think there is a difference between being asocial and introverted, even if it's minute. If introverts enjoy socializing to any extent, then they are not asocial. Asocial behavior is often seen as Avoidant Personality disorder, characterized by “hypersensitivity to rejection, unwillingness to enter into relationships, a strong desire for relationships, low self-esteem, and social withdrawal,” according research by Samuel M. Turner, Deborah C. Beidel and Ruth M. Townsley.
It is often confused with Antisocial Personality Disorder, which is characterized by hostility towards people, recklessness and disregard for others, but they can be extroverted, and it is not that one hates or is empathetic towards others, they are just afraid. Avoidant Personality Disorder has similar traits as introversion. Both can enjoy adventures and activities outside as well as inside their rooms, but asocialites do not have friends nor do they try to engage in even the shortest of social interactions because of fear of rejection. They can still long for social interactions, but they rather alienate themselves than risk the humiliation of a group ostracizing them.
Avoidant Personality Disorder can appear from ages as young as five and last a lifetime, so you probably know someone like this. They should not be treated like their personality is a disorder, and you can try to create an inviting space for them, but that probably will not get them out of their shell. Talk therapy and drugs, such as antidepressants are the best treatments for their symptoms, there is no "cure." This just goes to show that society can actually be divided into multiple personalities when it comes to socializing, not just introverts and extroverts.