Communication In "Indignation"

The book that I am reading for my English class is called "Indignation" by Philip Roth. The book takes place in the 1950s. The main character, Marcus, goes on his first date at his new college. . The girls name is Olivia and Marcus takes her out to dinner. After dinner Marcus drives to the local make out spot. The two participate in some sexual activity and Marcus is left speechless. For the next two weeks Marcus and Olivia ignored each other in class and outside of class until one day when they run into each other at the school book store. Marcus couldn't figure out why Olivia had interacted with him in that way and was scared to talk to her. In the book store Olivia explains to Marcus that she did that because she liked him. This is an example of mis-communication because Marcus knew this just didn't happen between two conventionally brought up young adults but Olivia did it to show her affection.