As someone who has great difficulty connecting with people I think about it all the time. I have an undergraduate degree in Communication, spanning both mass media technology and professional interpersonal communication. Learning about it may improve my ability to go through the motions, but that's about it. It's not going to significantly change my brain chemistry to alleviate my chronic anxiety.
I'm fascinated by human perception and behavior. Working on one of my COM papers led me to discover Semiotics, the study of signs and symbols and their use or interpretation. I'm reading Semiotics: The Basics by Daniel Chandler. A good companion would be something on Operant Conditioning and memory.
One day in the college cafeteria I overheard a group of students making fun of someone they knew but who was not present. Having a long history of being the subject of such gossip I have experience observing changes in the behavior of people who associate directly and even indirectly with the instigators of humor at the expense of someone else and the expense of myself.
Specifically, subordinates in a group who wish to show their loyalty to the leader will adopt the attitude of the leader toward a target (someone). Some members on the perimeter of the group will outwardly laugh at the leader's joke about the target, but find themselves harboring feelings of guilt for doing so. When they see the target every day, the memory of the joke with all its emotional baggage resurfaces. Their behavior changes significantly toward that person. They keep their distance, avoid eye contact or avoid the same areas or activities.
After a significant passage of time, the original joke may have been forgotten, but the emotional baggage is reinforced. After the memory of the initial event has faded, the remaining emotions that are triggered by the sight of the target must be rationalized. Some new reason must be created to explain why they feel the way they do about the target.
I call it Causal Drift. It's probably called something else, but the idea stems from how memory operates.
I assume couples break up over it. Someone says something hurtful but the other person lets it slide without saying expressing how they feel about what was said, the incident is forgotten, but the emotion is still there, and they accumulate.
It's not like this for everyone. A few lucky people can remember every detail and easily compartmentalize their emotions, but many people do not and are vulnerable to manipulation by cult-leaders, politicians and the mass media.
They are the ones who wind up voting against their own interests, developing paranoia-fueled conspiracy theories, or foaming at the mouth as they gyrate wildly, kicking over folding chairs at political town hall meetings.