Think about the feeling of being scared.  The feeling of fear and nervousness.  Think about how we all try to anticipate the subject, these are the Screen Tests.

They represent the power in filmmaking that allows the viewer to conjure feelings as they watch the subject.  In this horror series, starting from Kate to Tara, we watch the subjects experience something.  Feelings of their own that imply agitation, nervousness, and fear.  Whether they have chosen to be catatonic or stoic.

Enjoy.