Can we measure happiness/unhappiness using brain states?

[thedragonbook]

I came across this research and now am wondering if we can measure the transition from happiness to unhappiness and vice-versa using brain states?

 

http://newscenter.berkeley.edu/2011/09/22/brain-movies/

 

I mean, if we can reconstruct a part of a movie from brain states then why not happiness/unhappiness. I understand that different people have different opinion about happiness/unhappiness. But why not *ask* the person being scanned what makes him/her happy/unhappy and based on that map the brain states to happiness/unhappiness?

[davidivad]

you can measure these differences with an eeg.

the emotive headset has this very ability.

as far as controlling it, i believe you can to some degree by electrically stimulating the brain.

reconstructing part of a movie is much more complex.