A psychologist measures the IQs of 20 students who ingested a "smart pill" and 20 students who ingested a "sugar pill" in order to determine if the pill had an effect on intelligence. To ensure peak performance, she tests all of the students on Wednesdays. In this experiment, the independent variable is the

A defense attorney making use of the conditions of the American Law Institute model legislation on the insanity defense would have to provide evidence that her client

a. was mentally ill at the time of his offense. b. lacked substantial capacity to appreciate the criminality [wrongfulness] of his offense. c. lacked a knowledge of the law that he is accused of due to his mental illness. d. demonstrated substantial capacity to control his actions.

Harriet, a student nurse, was at first extremely uncomfortable at the sight of blood. After a month of working in the emergency room, she is no longer upset when confronted with serious injuries. Harriet has undergone

a. time out. b. shaping. c. desensitization. d. trial-and-error learning.