......I thought that yukkuri actually thought their 'shit' tasted good, so long as they didn't realize that they were eating their 'shit'.
I suppose you could argue that they still 'subconsciously' realize they're eating their own shit, and so that's why it still tastes bad to them, but that might be giving them too much credit....
Oh yeah, do you mind if I use this experiment in the story I'm writing? (as in an isolation experiment, not actually copying this one word for word.)
......I'm not a psychology guy or anything, so I could be wrong about this, but I don't think going insane would affect how foods taste.... Sweet things will still taste sweet, because they still set off the same taste-buds. I mean, the yukkuri is still eating its food isn't it? while it may be mid-grade food, I'd imagine its still at least a little sweet. So that kind of implies that the yukkuri still thinks that sweet foods taste good.
I've revised my theory. Yukkuri paste has distinct flavoring based on it's condition. This also applies to "urine" and corpses. It's still sweet bean paste, but it's smell and taste are different in a way that is distinct to yukkuri. Recognition depends mainly on intelligence. A smarter yukkuri will consistently recognize the difference, and be disgusted, even when they don't specifically recognize that it's "poop." Dumber ones just know it's sweet, so unless the way it's presented to them reminds them of where it came from, they'll take it as food.
Well, yukkuri 'poop' bean paste that is oft considered to be near expiration/actually expired, so its not too far fetched that it tastes different enough that a reasonably intelligent(by yukkuri standards) yukkuri could tell the difference. As far as smell is concerned, here's my theory: A Yukkuris sense of smell is actually based on 90% 'belief' and only 10% on actual scent. Simply put, if a yukkuri believes that something stinks, then as far as the yukkuri is concerned, it does. A perfect example is the yukkuri 'poop' we've been discussing. Now, I've never encountered red/black bean-paste on its own, so I don't really know how strong its smell is, or if it even has much of one, so remember that. Personally, I don't think bean-paste would have that strong of a scent, and if it does have one, it would probably smell sweet. So why would a yukkuri say it stinks? because the yukkuri knows its poop, and yukkuris firmly believe that poop = stinky, regardless of whether or not their poop actually is stinky. So, because their sense of smell is mostly 'belief' based, they will perceive their poop as 'stinky'. However, if the yukkuri doesn't know that that bean-paste is actually poop, then they won't think its stinky, and may even think it smells like 'sweet-sweets'.
On yukkuri 'urine'. Its just sugary water, unless you add something else to it, I don't think it would smell or taste any different, even to a yukkuri(so long as they don't realize its 'pee'). On the other hand, There's almost NO images of a yukkuri consuming another yukkuris/their own pee. I think I've only seen 2 or 3 images total that have a yukkuri consuming yukkuri pee, and its usually been in a 'do it or die' situation....So perhaps there is a difference..... For corpses, I'd actually think it depends on how long the yukkuri has been dead, and the method of death. Obviously, a 'corpse' would taste bad if its been there for a few days. If it was fresh, on the other hand, it would probably be considered tasty by any yukkuri, if they don't know it was formerly a yukkuri, or if they're under special circumstances(such as the 'now, please, eat up!' scenarios). I mention the method of death as a determining factor in the corpses taste simply because there are many ways the flavor of the corpse could be affected by how they died. I.E. If they died from eating something spicy, the corpse might retain some of the spiciness. If they died from stress, abuse, or loneliness, the bean-paste may already be rotted when they die. (My theory: stress, pain, fear, and excessive loneliness, all cause the release of the chemical that 'sweetens' the paste, but the chemical also causes the paste to expire/rot faster. So if they experienced enough suffering, the amount of that chemical in their system would kill them via rotting their insides beyond survivability.)