I would like to measure the change in emotional state in response to a question. For example, asking the question, "What is your favorite color?" would be fairly benign; I would not expect any change in emotional state. However, I would expect a strong emotional response if I asked "What type of person do you hate?" or "Have you ever smoked marijuana?"
Ideally, we would measure this immediately after asking the question. Does anybody have any suggestions on how this can be done, or how it has been done reliably in the past? I have access to surveys and special cameras (thermal, pupil analysis, etc) if it helps.
Edit: To clarify, I'm more interested in measuring the level of emotional arousal more than measuring what specific emotion somebody is feeling. For example, I don't care if somebody is frightened or angry, just the extent to which the emotion caused arousal.