Edit: Sorry, editing messed up the formatting. Trying to fix...
Seems like a pretty large leap from certain behaviours of rats to the natural-language meaning of “wanting” and “liking”. Far-reaching claims such as this one should have strong evidence. Why not give humans drugs selective for either system and ask them? (Incidentally, at least with the dopamine system, this has been done millions of times ;) The opioids are a bit trickier because activating mu receptors (e.g. by means of opiates) will in turn cause a dopamine surge, too)
(Yes, I should just read the paper for their rationale, but can’t be bothered right now...)
Edit: Sorry, editing messed up the formatting. Trying to fix...
Seems like a pretty large leap from certain behaviours of rats to the natural-language meaning of “wanting” and “liking”. Far-reaching claims such as this one should have strong evidence. Why not give humans drugs selective for either system and ask them? (Incidentally, at least with the dopamine system, this has been done millions of times ;) The opioids are a bit trickier because activating mu receptors (e.g. by means of opiates) will in turn cause a dopamine surge, too)
(Yes, I should just read the paper for their rationale, but can’t be bothered right now...)