The size of the pupil can be affected by our emotional state. Sensing something pleasing widens the pupil, and sensing something unpleasant contracts the pupil.
Work Step by Step
This is discussed on pages 496-498.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.