Confusion is painful

Confusion is not a headache exactly: the head just feels a bit strained, almost like we were squinting too long. We want the lecturer to stop talking so the feeling can go away. We want to quit reading and close our eyes. Often, later, when we are just thinking about the idea, this feeling of confusion returns. This is the inescapable feeling of learning something new. When we sense this feeling, it signals a break in the learning session: A swimming head absorbs nothing. Professional teachers recognize this: they know how to spot "temporarily interesting," "moderately painful" and "severely confused" on the face of their students.

We notice whole entities, but we describe in parts

The idea that a person can be ugly or pretty gives us a glimpse into how we perceive. We do not see faces as a collection of separate features. We see them as a sum total – a face. If you believe that you’ve seen ugly faces, and you probably do, it is only because you see in this peculiar way. What you’ve really seen are large noses, misshapen eyes, bushy eyebrows, jutting chins and mousy ears. Any one of these features alone might not make a person’s face ugly. It is some combination of these, or other features, that you probably find ugly.