A fictional test from the novel DoAndroidsDreamOfElectricSheep? by PhilDick (which was made into the film BladeRunner, where it gained wider notoriety). It is used to detect androids by measuring their physical responses to questions. Here is a transcript of an appropriate scene in the film: http://www.stradavox.com/BR/dialogs/d004.htm
The idea behind the test is that human beings cannot fully control their physical responses to emotions; for example, fear stimulates a rush of adrenaline through our system, which causes us to hyperventilate. The Voigt Kampff Test asks questions that should evoke a significant emotional response in most humans, and measures the subject's physical response. Significant variation from normal human responses (taking into account the fact that any human will respond abnormally to some questions, which is why several dozen questions are normally required) indicates that the subject is an android.
Quote: "Replicants are like any other machine. They're either a benefit or a hazard. If they're a benefit, it's not my problem."