Not an exact science folks.

So tonight we're faced with a pretty big deal in the Love Island villa. The lads will be asked questions, while hooked up to a lie detector. You know those machines that react to your heart rate to catch you out on a lie? Well, I'm here to tell you to take it all with a pinch of salt, because it is not an exact science. Lie detectors , also known as polygraph tests, are designed to be capable of detecting deception through “analysis of physiological responses to a structured, but unstandardised, series of questions,” according to the American Psychological Association. By monitoring a person's heart rate, blood pressure, respiration, and skin conductivity, the instrument can (in theory) determine whether the a human is telling a lie. It is assumed that lying causes stress, hence the reaction of the polygraph. But what if you are being filmed for television while taking the test? Or what if someone you're dating is sitting there, watching you answer questions about them? Surely that would result in a level of stress that may result in a test fail. Hence why we should be skeptical of the test.