Lie Detector Essay

553 Words3 Pages
1. If emotions always show up on our faces, can we use faces as good lie detectors? Give one or two reasons why we can and one or two why we cannot. -Lie detectors are designed to detect changes in sympathetic activity. They do this by measuring changes in blood pressure, heart rate, sweating, and respiration that an individual makes to a question. It is assumed that when a person is lying there will be an increase in arousal and thus corresponding changes in blood pressure, heart rate, etc. the examiner compares responses to neutral statements. When not relying on a lie detector machine but instead facial expressions alone there could be many reasons that facial expressions alone could be successful or unsuccessful. Reasons we can rely on facial expressions alone. * According to the James-Lange Theory (the first physiological theory) “emotion follows upon the bodily expression” (CM). James Theory states that in an emotion-arousing experience, one would first experience muscular responses, and only after these occur is an emotion experienced. James believed that bodily reactions, like facial expressions, are unconscious, unlearned behaviors (CM). Now looking at this theory one could say that we could use facial expressions as lie detectors because your facial muscles would react before you feel the emotion tied to it. * Reasons we cannot rely on facial expressions as a lie detector According to another theory, those of Walter Cannon which states that emotions will occur even without bodily changes which send messages to the brain are eliminated. Cannon believes emotion occurs at the same time as the facial expression and not because of them as believed by James. This theory would say that: if someone jumped out at you, you would scream and have a scared look on your face at the same time. According to this theory facial expressions would not be
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