There is a large number of categories. Whereas the alphanumeric character recognition problem may have only 36 categories, the facial recognition problem can have millions or even billions.
– Dr. Woodrow Wilson Bledsoe for Panaromic Research, Inc; FACIAL RECOGNITION PROJECT REPORT (March 6th 1964)
A nervous tic, an unconscious look of anxiety, a habit of muttering to yourself—anything that carried with it the suggestion of abnormality, of having something to hide. In any case, to wear an improper expression on your face (to look incredulous when a victory was announced, for example) was itself a punishable offence. There was even a word for it in Newspeak: FACECRIME, it was called.
– George Orwell, Nineteen Eighty-Four. (1948. Chapter 5, paragraph 65)