You’re talking about conscious value placement. Indeed, this is a highly subjective thing and depends on all kinds of complex factors like cost vs. benefit, personal relevance, and all number of other things. I don’t disagree with what you’re saying here at all.
What I’m talking about is unconscious, instinctive neurochemical reactions in response to stimuli. Seeing a clear indication of progress towards something as a direct result of your actions triggers a release of dopamine in your brain. It just does. That’s just how our brains work. That doesn’t necessarily mean you will like or ascribe value to the thing that caused the release of dopamine. Again, that’s a much more complex phenomenon, and not what I’m talking about.
That’s just factually incorrect. It will have to be a net benefit for a person to consciously consider it worthwhile, and the neurochemical reward is a factor in that cost/benefit analysis - albeit one most people won’t consciously register. It is not the only factor, and I do not claim it is. I claim only that it is a factor, and that is pretty much inarguable.
Your brain’s reward system doesn’t work that way. It doesn’t have a concept of value in that sense, that’s abstract thinking, which is handled more by the frontal lobe. The reward system just goes “do thing -> release dopamine” and another part goes “dopamine good, want do thing so get dopamine.” Of course, if doing the thing to get the dopamine is also unpleasant in some way, your rational brain might decide it isn’t worth it. That is, again, not what I’m talking about.