Affectation often points out a fake action done to look real and impress others. His laughter was an affectation; he wasn't truly amused.
Pro Tip 2/3
Social Impressions
Used to describe actions that people hope will make them look good in social situations. Her constant charity work was seen as an affectation by her colleagues.
Pro Tip 3/3
Unfavorable Connotation
Usually has a negative tone, implying the person is being insincere. His concern for the environment was mere affectation.