One such theory is psychoanalysis.
One aspect here is passive: influence -- humans exert power over one another simply by being present and triggering associations the affected person has with previously encountered humans.
Another is more active: 'intersubjectivity' -- people reach out into a sharing of ideas with another person based on how we decide to connect, but since there is only a narrow stream of conversation, we choose roles, and cast them in roles, in conversations already in progress. Otherwise, establishing communication would be slow and laborious. And without the filters imposed by roles the topic could not be negotiated efficiently unless it were urgent.
These two things can make up a 'transference', where each individual is really interacting with a selected part of the other and each is interpreting the part they have selected to represent a set of ongoing conversations with groups, roles or other significant people. Only as each actual person varies in response from what would be predicted to come from the persona or set of ideas they are being selected to represent, is there actual human contact, which modifies the content of the structuring roles and assumptions.
This explains how most conversations can come into such rich territory so quickly, instead of having to build up the relationship from scratch. But it also means that we are constantly confused by expectations, and not directly open to hear what is being communicated except through a set of filters build out of our biases.