I was interested by the offhand suggestion in a recent Session announcement that Black IPA is becoming a "largely irrelevant curiosity". To be honest, I'm sufficiently far out of the craft loop that I can't say whether that's true or not, but it's certainly a style that I see rarely and am often underwhelmed by when I do try it.
This isn't to say that there aren't some great examples - Buxton's Imperial Black particularly does it for me - but as a style it seems to be particularly easy to do badly. I suspect that the one important reason for that - and the reason that it'll probably be a while before I try brewing one myself - is probably that it's essentially a bit of a ventriloquist's act, making the big, bright, tropical hop flavours of an IPA unexpectedly appear in what looks like a glass of stout. This seems like magic if it's done well, but if the hops flavours don't speak loudly and clearly then we can miss them entirely, rendering the whole trick a bit pointless. For brewers, myself included, who can't reliably pull off big, bright hop flavour, the safest bet for now is probably to stick to hoppy beers that look like hoppy beers, where the flavours stay in line with what the drinker expects based on the appearance of the beer, and where we'll probably get the benefit of the doubt if we don't quite hit the perfect hop schedule.
All of this calls to mind the famous "white wine dyed red" experiment, which isn't quite the knockout blow to wine tasting that it's sometimes presented as, but which does serve as a useful reminder that our senses interact and influence each other rather than each operating in a vacuum.
Another area where this sort of interplay of flavour and appearance rears its head is the perennially vexed issue of murky IPA. There often seems to be a clear generational divide between people who love them and people who hate them, and while the vehemence with which this apparently trivial matter of taste is pursued makes it look suspiciously like a proxy for bigger issues, the existence of a division in the first place seems like an obvious example of a learned association. For a long time, a cloudy pint was the all-too-common sign of dodgy beer - something that'll taste crap and probably give you the shits. Given this background, I can see how someone might be put off by a murky beer regardless of how it tastes. But our expectations for cask ale have generally risen over the past decades and that sort of properly off pint is mercifully rare, so for many beer drinkers the only real association for hazy beer is the big, resinous, hoppy pale ales themselves. This means that if anything we're actually going to prefer a hoppy beer with a bit of haze over a similar tasting one that's pin bright, because it looks the part as well as tasting it.
What conclusion to draw from this? Maybe that as haze becomes an increasingly accepted and expected feature of hoppy IPA as a style, the only real hope that the murk-o-phobes have got is to bring back the truly off pint. That or start learning to live with it.