Final answer:
Shawn's tendency to smile in response to his sister-in-law's demeanor is not influenced by individualism, which emphasizes personal independence rather than group dynamics.
Step-by-step explanation:
Shawn's reaction to his sister-in-law's presence is NOT caused by D. individualism. Individualism is a social theory favoring freedom of action for individuals over collective or state control. In the case described, several psychological phenomena related to social interaction and mirroring behaviors are at play, which include:
Automatic mimicry: The unconscious imitation of someone else's behavior, such as smiling when you see someone else smile.
Mood linkage: The phenomenon where individuals tend to share the moods of the people around them.
Chameleon effect: The subconscious matching of one's actions or emotions to those of others in one's current social environment.
The fact that Shawn starts smiling even before his sister-in-law says something funny is likely due to mood linkage or the chameleon effect, not individualism which is unrelated to these mimicking behaviors.