Final answer:
Lie detectors measure physiological arousal but cannot determine its cause; thus, while they can suggest deception, they may also indicate other emotional states or reactions.
Step-by-step explanation:
The accuracy of lie detectors, based on their ability to differentiate emotions, can be assessed through different theories of emotion. According to the James-Lange theory of emotion, a polygraph should be quite accurate since it posits that emotions result from physiological arousal, and different patterns of arousal are connected to different emotions.
However, this may only be true to a certain extent as physiological responses can be similar across various emotions, requiring cognitive appraisal to discern the exact emotion, as per the ideas of Schachter and Singer. These researchers found that participants injected with epinephrine, which causes physiological arousal similar to the fight-or-flight response, did not report emotional changes if they were expecting the physiological effects. On the contrary, participants who were not anticipating these physiological changes were more likely to use context to interpret their arousal and subsequently report emotions like euphoria or anger.
Polygraph tests measure physiological responses, such as heart rate and respiration, to assess honesty. Due to the variability and potential misattribution of arousal causes, the final answer to whether a lie detector can accurately determine the reason for increased physiological arousal is a) True.
Lie detectors or polygraphs cannot discern the specific reason for an individual's physiological arousal; they can only indicate that there is arousal present. This can lead to false results, as various factors unrelated to lying may cause similar physiological responses, such as nervousness, excitement, or fear.