If you're saying actual human preference is determined by human biology and brain architecture, but mostly independent from brain content, this is a very new claim that I don't remember hearing ever before.

Hmm, I think I've said this many times already. Of course beliefs are bound to change preference to some extent, but shouldn't be allowed to do this too much. On reflection, you wouldn't want the decisions (to obtain certain beliefs) of your stupid human brain with all its biases that you already know not to endorse, to determine what should be done with the universe.

Only where such decisions manage to overcome this principle, will there be change, and I can't even think of a specific example of when that should happen. Generally, you can't trust yourself. The fact that you believe that X is better than Y is not in itself a reason to believe that X is better than Y, although you might believe that X is better than Y because it is (because of a valid reason for X being better than Y, which your belief in X being better than Y isn't).

So when beliefs do change your preference, it probably won't be in accordance with beliefs about preference.