that preferences are brain states, which are also genetic and environmental phenomena? I thought they were mental phenomena. — Harry Hindu

Preferences are brain states. Mental phenomena are identical to particular brain states.

Brain states/mental phenomena are not identical to genetics and environmental factors, though those things are important factors in why brains develop as they do.

Factors are not identical to the product. Causes are not identical to the effect. — Harry Hindu

Exactly. Hence why it's important to be careful with "based on" as I explained above.

Preferences are brain states. Mental phenomena are identical to particular brain states.

Brain states/mental phenomena are not identical to genetics and environmental factors, though those things are important factors in why brains develop as they do. — Terrapin Station

So preferences are not identical to genetic and environmental phenomena, which is to say preferences are based on something that arent preferences. Another way we could say it and it mean the same thing is that preferences depend on genetic and environmental phenomena.

Sure, again "That would only be the case if you're defining 'based on' as being about contributing factors that aren't identical to what we're talking about. But of course, one wouldn't have to use 'based on' that way," and I explained a reason we'd want to be careful with using the former sense in this case.