The experiment Gladwell describes is setting up the participant to respond with a particular emotion (surprise). If the participant responds to the altered hallway and grave-looking friend with surprise
and a stereotypically surprised expression (i.e., mouth agape, wide eyes, and an audible gasp, perhaps), it will imply that there is a meaningful connection between cultural associations with facial expressions and genuine emotional responses. If the participant’s feeling of surprise is paired with some other facial expression, however, this finding would suggest that facial expressions are more varied and nuanced than one might initially expect them to be.