What is "The GRE" as noted in the nonfiction book, Whistling Vivaldi?

The Gree, or Graduate Record Exam, is a standardized test whose scores most universities consider as part of whether or not to accept graduate student applicants. Most college students are capable of taking it, but will struggle to perform particularly well on it. For this reason, it makes a good test of both academic capabilities, and of a person’s level of stress in response to a certain task. Steele and his colleagues frequently use it in their experiments to see how the presence or absence of certain stressors, like reminders of certain stereotypes, cause enough distress or distraction to affect a person’s performance.