Interaction adaptation theory (IAT) seeks to explain how individuals will react in dyadic exchanges based on their expectations, desires, and requirements for that situation. This paper explains the foundations of IAT and examines IAT within the context of cross-sex heterosexual friendships where one or both members of the relational dyad wishes to escalate the relationships level of intimacy. Existing social networks are very influential on relationships likelihood to escalate. Similarly, an individual’s attachment style will also impact their willingness to escalate a relationship. Societal norms also play a role in how individuals expect their relational partners to behave. There are also significant differences between males and females in regards to adaptive behaviors and expectations within a relationship. In general, IAT research should be expanded to the context of different types of established relationships. Most of the existing research focuses on interactions between strangers.