Expectancy violations theory is an attempt to explain the way people react to unexpected actions from their peers as well as the meanings that people attach to incursions on their own personal space. According to this theory, communication consists of the swapping of information rich in relational content, and expectancies come from socially established norms as well as individual traits of those in the conversation.
Expectancy violations theory assumes that people have a minimal degree of free will because its belief is that humans have the ability to observe and interpret the relationship and degree of amity between themselves and those with whom they interact. After that, they have the choice of whether to violate that other person's expectations.
Another assumption of this theory is that norms exist for all types of communication. When those norms experience violation, the outcomes are specific and usually predictable. The usefulness and practicality of expectancy violations theory come from the assumption of universal conversational norms as well as universal reactions when those norms are broken.
Consider a man talking to a woman at a party whom he has just met. If he is not receiving positive feedback in the conversation, he might try to stick to what he thinks women expect in that situation, such as asking questions about her or making some light jokes about the party. If he gets some positive feedback, though, he is likely to go beyond the expectations of that first conversation by asking her to leave with him for some coffee.