The guilty knowledge test (GKT) was designed by David Lykken. According to the Lilienfeld textbook, this test is an alternative to the polygraph test that relies on the premise that criminals harbor concealed knowledge about the rime that innocent people don't. The GKT measures suspects' recognition of concealed knowledge, not lying. Furthermore, the guilty knowledge test uses multiple choice questions to test for knowledge only a guilty person could posses.
For example, authorities are interrogating a man they suspect of being the killer of a murder case. When using the guilty knowledge test, they would ask the man a control multiple choice question to find the man's normal physiological response then they would ask a multiple choice question such as "what was the murder weapon?" Then the interrogator would read off the choices. The idea of the GKT is that the man will show increased physiological response such as breathing rate, heart rate, blood pressure, and galvanic skin response when the correct murder weapon is read. If the man does show increased response when the real murder weapon is read, he is most likely guilty of the crime.
In conclusion, the guilty knowledge test in an effective method used by interrogators to get suspects to subconsciously admit to crimes by using multiple choice questions while measuring increases in physiological response.
Below is a picture of David Lykken, who invented the guilty knowledge test.