Shawn's sister-in-law always has a smile on her face and a joke to tell. the moment she walks into shawn's house he starts smiling, even before she says something funny. this is not caused by:

I believe the answer is: Individualism

Individualism is the tendency to distant oneself from a situation that required collectible interaction with other people in social group.

Paying attention to someone who's telling a joke is not something that caused by individualism.