From The Guardian:
Do our eyes betray us when we lie? The US government hopes to find out.
In Ridley Scott's 1982 sci-fi classic, Bladerunner, the police have a problem. The wayward androids they are pursuing behave so much like humans, they have a tough time telling them apart.
They turn to the Voight-Kampff test, a futuristic version of the age-old polygraph, to help them out. During the test, subjects are grilled with a list of questions, while their physiology is monitored. In particular, the test looks for abnormal eye responses that might indicate the subject isn't human.
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