6.54 The z distribution and a “super recognizer”: According to a news article, “Friends call Constable [Gary] Collins Rain Man or Yoda or simply The Oracle. But to Scotland Yard, London’s metropolitan police force, he is known as a ‘super recognizer’” (Bennhold, 2015). Prosopagnosia, also known as face blindness, is a disorder in which the sufferer cannot recall faces, even of people they know well. About 2% of us experience face blindness. Collins is the opposite; he’s among the 1% to 2% of us who recall almost every face they’ve ever seen. As you can imagine, this gives him an almost superhero ability to help solve crimes—a “Facebook of the mind.” A snippet from a security camera, and Collins has a name for the suspect. Most of us, however, fall in between prosopagnosics and super recognizers.

a. Imagine a z distribution for face recognition ability. Give an estimate of the z score that Collins and other super recognizers are likely to fall above. Explain your answer.

b. Now give an estimate of the z score that people with face blindness are likely to fall below. Explain your answer.

c. Between approximately what z scores do most of us fall? Explain your answer.