Using eye movement to detect lies contrasts with polygraph testing. Instead of measuring a person's emotional reaction to lying, eye-tracking technology measures the person's cognitive reaction. To do so, the researchers record a number of measurements while a subject is answering a series of true-and-false questions on a computer. The measurements include pupil dilation, response time, reading and rereading time, and errors.
The researchers determined that lying requires more work than telling the truth, so they look for indications that the subject is working hard. For example, a person who is being dishonest may have dilated pupils and take longer to read and answer the questions. These reactions are often minute and require sophisticated measurement and statistical modeling to determine their significance.[...]
Besides measuring a different type of response, eye-tracking methods for detecting lies has several other benefits over the polygraph. Eye tracking promises to cost substantially less, require one-fifth of the time currently needed for examinations, require no attachment to the subject being tested, be available in any language and be administered by technicians rather than qualified polygraph examiners.
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