The Voight-Kampff test (the so-called "empathy test") in the film has been bothering me for some time...

It is acknowledged in the film that the test can give a false negative - Rachael would have given a false reading in a normal test, as would the other Nexus 6's, according to Tyrell.

At some point Rachael asks if Deckard has ever "retired" a human by mistake but he dodges the question and answers something else: "Simulants are either a benefit or a hazard. If they're a benefit, it's not my problem".

So, as the VK test measures empathy and reactions to things that most people would find distasteful, would a psychopath create a false positive? Or would there be other mental illnesses/personality disorders that might cause a false positive?

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    Autistic people might also have problems Commented Jan 7, 2013 at 16:43

3 Answers 3


It is unfortunately a very difficult question to answer from the movie alone. Yes, the VK test is challenged in the movie by Rachel - and that it takes very many more questions for Deckard to conclude that she is a Replicant - but that is about the extent of the analysis of the test in the movie. One can imagine from this scenario where a Replicant with artificial human memories almost fools the test, that a human with emotional issues involving empathy may not test as a human. However that (and the opening scene) is the extent of the use of the test in the movie - to introduce empathy as a key difference between humans and replicants, but also to blur the boundary between the two.

The novel from which the movie is loosely adapted (Do Androids Dream of Electric Sheep) the test is discussed in more detail. In the society of the novel most animals in the world have been wiped out, and most if not all humans keep one or more animals as pets. To not care for one or more animals would be unusual. Deckard owns an 'electric sheep' a replica animal, but wishes he could afford a more expensive real pet and is planning to spend his bounty money on one. The fact that he has not to date put enough of a priority on owning a real animal despite his good job is a suggestion in the movie that perhaps Decard's humanity is questioned. As a result the VK test in the novel seems particularly geared towards questions about empathy towards animals, or even insects - as abusing or killing even an insect would be taboo in this society.

In the novel, the issue surrounding the validity of the test, and indeed the validity of Deckard's claim to being human at all - is challenged by his discovery of an entire shadow police department, staffed by what he believes are androids. The blade-runner from this alternative police department uses an entirely different test to distinguish android from human - one that relies on the speed of reflex actions. The two blade runners distrust each other and debate whether one or the other is an android and whether they should take one or other of the tests.

The key thing from both the movie and the novel is the question .. what is human? The validity of the test ceases to be important in both.

  • I've voted your answer up because it is very complete and well considered. However, I was asking only about the film as the book is far less ambiguous, especially given how deeply entrenched Mercerism and the little black boxes are. Still, it seems possible in the book as Deckard does try hard but is still not very good at showing empathy. Abusing or killing animals or insects would be taboo and a psychopath might be able to fake it without close scrutiny but would still not be able to show enough empathy to pass the test, I think. Commented Apr 19, 2012 at 21:13

Since there is no VK test to, well test, there can be no definitive disproval, but... The stated purpose of the test is merely an effective ruse. In such a way that is how "lie-detector" tests are employed. The placebo is better than no seemingly objective leverage.

Obviously "blade runners" are judge, jury and executioners. So yes! Simply put, all positives depend upon the tester. I'd say the device is more of one to the plot. It is a jumping off point for the scientist in us to speculate what is outside of "reality" and take our understanding of what is "human", to question in a way that cannot be quantified.

The crux of the story is in our feeling doubt and therefore remorse. Understood artistically, the subject switches places with the object. The test giver has to employ empathy and make determinations about humanity. That neatly explains evasiveness Deckard has about his "retirements." Also it exposes his doubt as to his own humanity.

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    I disagree about the "placebo". The equipment they employ is very sophisticated and the Blade Runners appear to rely quite heavily on it, as can be seen with Leon at the begging of the film. I hadn't appreciated the Judge Dredd overtones before until reading your answer, but they are very strong. And i think you're right, the results are subjective. Commented Apr 19, 2012 at 21:02

This was addressed in the source story, Do Androids Dream of Electric Sheep?

Simply put, a human with so little social empathy as to be able to get a false-positive on the test wouldn't have been able to function in society. They would have already been immediately institutionalised.

In theory you could get a false-positive out of someone who was schizophrenic or psychopathic, but that person would have already been detectable as human by other means.

“One day, a few weeks ago, I talked with Dave about exactly that. He had been thinking along the same lines. I had a memo from the Soviet police, W.P.O. itself, circulated throughout Earth plus the colonies. A group of psychiatrists in Leningrad have approached W.P.O. with the following proposition. They want the latest and most accurate personality profile analytical tools used in determining the presence of an android—in other words, the Voigt-Kampff scale—applied to a carefully selected group of schizoid and schizophrenic human patients. Those, specifically, which reveal what’s called a ‘flattening of affect.’ You’ve heard of that.”
Rick said, “That’s specifically what the scale measures.”
“Then you understand what they’re worried about.”
“This problem has always existed. Since we first encountered androids posing as humans. The consensus of police opinion is known to you in Lurie Kampff’s article, written eight years ago. Role-taking Blockage in the Undeteriorated Schizophrenic. Kampff compared the diminished empathic faculty found in human mental patients and a superficially similar but basically—”
“The Leningrad psychiatrists,” Bryant broke in brusquely, “think that a small class of human beings could not pass the Voigt-Kampff scale. If you tested them in line with police work, you’d assess them as humanoid robots. You’d be wrong, but by then they’d be dead.” He was silent, now, waiting for Rick’s answer. “But these individuals,” Rick said, “would all be—”
“They’d be in institutions,” Bryant agreed. “They couldn’t conceivably function in the outside world; they certainly couldn’t go undetected as advanced psychotics—unless of course their breakdown had come recently and suddenly and no one had gotten around to noticing. But this could happen.”

Do Androids Dream of Electric Sheep? - Chapter 4

Note that a functioning sociopath or psychopath (one with sufficient empathy to get along in society) would still show up as human.

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