Sure, that’s true. I suppose you could have a split-brain person who is happy in one hemisphere and not in the other, or some such type of situation. I guess it just depends on what you’re looking for when you ask “is someone happy?” If you want a subjective feeling, then self-report data will be reliable. If you’re looking for specific physiological states or such, then self-report data may not be necessary, and may even contradict your findings. But it seems suspect to me that you would call it happiness if it did not correspond to a subjective feeling of happiness.
Sure, that’s true. I suppose you could have a split-brain person who is happy in one hemisphere and not in the other, or some such type of situation. I guess it just depends on what you’re looking for when you ask “is someone happy?” If you want a subjective feeling, then self-report data will be reliable. If you’re looking for specific physiological states or such, then self-report data may not be necessary, and may even contradict your findings. But it seems suspect to me that you would call it happiness if it did not correspond to a subjective feeling of happiness.