When people suspect that they've been in contact with a ghostly presence, it's often not as concrete as clearly seeing the form of a ghost or watching a possessed doll walk towards them in a threatening manner.
Most of the time, what they've encountered is a little harder to explain and boils down to an unexplained sense of dread they get from a room or an object. Sudden temperature changes in a room will sometimes do this, but there's often just a prevailing sense that we should get out right away.
Even if the things they might blame on these feelings aren't real, the feelings themselves certainly are and it's hard to blame anyone for wanting to get away from the things we're about to see today.