On my morning walk with the puppers today, I was listening to the audio book the Physics of God by Joseph Selbie and it mentioned something I found fascinating. It spoke of how those with multiple personalities a.k.a. dissociative identity disorder (DID) have shown the ability to completely change their physiology within seconds to minutes. Examples include changes in eyesight, eye color, scars, allergies, diseases, EEG patterns, body temperature, voiceprint, and so forth. I went so far as to track down some of the original studies, such as the ones on eyesight, and the claims are legit. The shape of the eyeball actually changes. Actors faking DID are not able to achieve the same changes.