The technique here is to show us Cole Sear’s patient file before we actually meet him. By feeding us tiny bits of exposition, Shyamalan creates anticipation for meeting the character. 

Before we ever even see Cole Sear, we’re interested in him and he engages our empathy because we know he’s isolated, suffering and experiencing difficulties. 

No matter what the character is like when he first comes into the scene and starts doing things, we’ll have these nuggets of information in the back of our heads.