Final answer:
Michael, who shows reduced emotional expression, is the one among the given options who displays a negative symptom of schizophrenia. John, Sarah, and Emily exhibit positive symptoms with their hallucinations, delusions, and disorganized thinking.
Step-by-step explanation:
Schizophrenia is characterized by a range of symptoms, commonly divided into 'positive' and 'negative' categories. Positive symptoms include hallucinations, delusions, and disorganized thinking, all of which represent an excess or distortion of normal functions. Negative symptoms, on the other hand, are characterized by a reduction or loss of normal functions, such as reduced emotional expression, loss of pleasure, and loss of basic drives.
Considering the options given by the student, Michael, who shows reduced emotional expression, is the one who displays a negative symptom of schizophrenia. John and Emily, experiencing hallucinations and delusional beliefs respectively, along with Sarah, who has disorganized thinking, are displaying positive symptoms of the disorder.