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.

I think when you parse this out you realize that there are a lot of other factors at play here, it's not just a "belief in belief" thing.

Treating someone nicely has an influence on how they subsequently treat you and others. So it's not so much that you're believing someone is nice when they're not, it's that you're believing that they do not have a fixed property state of "niceness", that it is variable dependent on conditions, which you can then manipulate to promote niceness, for the benefit of yourself and others.

None of this is belief in belief. When you look closer you see that you are comparing two different things: how nice Bob has been in the past and how nice Bob will be in the present/future, dependent on what type of environment he is in, and you are thus modifying your behavior on the assumption that your contribution to the environment can make it such that Bob will be nice, or at least nicer. And there is evidence to support this assumption, so it's not irrational to expect Bob to be(come) nice when treat him nicely accordingly.

It's just misleading to phrase it as "I benefit from believing perople are nicer than they are," because what you mean by the first "are" (will be) is not the same as what you mean by the second "are" (have been).

I think the idea behind this is that he wishes reality played out in such a way that, to a rational observer, it would engender belief. It's a roundabout way of saying "I wish reality were such that..."

Only retroactively. Our memories are easy to corrupt. But no, I don't think you can be happy or unhappy at any given moment and simultaneously believe the opposite is true. There's probably room for the whole "belief in belief" thing here, though. That is, you could want to believe you're happy when you're not, and could maybe even convince yourself that you had convinced yourself that you were happy, but I don't think you'd actually believe it.

True. Still, the method of measuring serotonin and dopamine levels would offer no benefit over a self-evaluation, since you can't implement it retroactively.

Not everyone can be hypnotized. About a quarter of people can't be hypnotized, according to research at Stanford.

I've tried to be hypnotized before and it didn't work. I think I'm just not capable of making myself that open to suggestion, even though I would have liked to have been hypnotized.

I heard from one of my psychology professors that those on the extreme ends of the IQ spectrum (both high and low) have more trouble being hypnotized, but I'm not sure if this is actually true. The Stanford research showed that hypnotizability wasn't correlated with any personality traits, but I probably wouldn't consider IQ a personality trait.

I think it's not underconfident because our over-confidence is so high that it really is hard to be pessimistic enough to match reality. Depressed people seem to have just enough pessimism to compensate (but not overcompensate) for this bias. I don't think that necessarily makes them have more common sense. Even just in terms of being more realistic, this is only one bias that they compensate for. It's not like depression magically cures any of the other biases.

Depressed people also have a tendency to have an external locus of control, and that is not necessarily rational. You may not be able to control the situations you're in, but it's often the case that your actions do have a significant impact on them, so believing that you have very little or no control is often not rational.

I'd heard of the connection between depression and more accurate perceptions (notably, more accurate predictions due to less overconfidence), but I wasn't aware of the causal direction. It had been portrayed to me as being that the improved perception of reality was the cause of the depression. Or maybe I just mistakenly inferred it and didn't notice. I didn't know it actually went the other way, though now that I think about it, that actually makes a lot of sense.

Personally, I find that imroved map-territory correspondence leads to more happiness, at least the improved rationality which results from learning Rational Emotive Behavior Therapy. It's not just losing illusions that helps. It's better understanding yourself, better understanding what is actually causing your emotions, and realizing that you have a more internal locus of control rather than external regarding your emotions. It's liberating to be able to stop an emotional reaction in its tracks, analyze it, recognize it as following from an irrational belief, and consequently substitute the irrational emotion for a rational one. It helps especially with anger and anxiety, as those have a tendency to result from irrational, dogmatic beliefs.

How would you calibrate a brain scan machine to happiness except by comparing it to self-evaluated happiness? You only know that certain neural pathways correspond to happiness because people report being happy while these pathways are activated. If someone had different brain circuitry (like, say, someone born with only half a brain), you wouldn't be able to use this metric except by first seeing how their brain pattern corresponded to their self-reported happiness. It seems to me that happiness simply is the perception of happiness. There is no difference between "believing you're happy" and "being happy." You can't be secretly happy or unhappy and not know it, 'cause that wouldn't constitute happiness.

Hm... You make a good point. I'm not sure I understand this conceptually well enough to have any sort of coherent response.