This is one of those “ghost maybe” occ posts where you should mentally insert a “maybe” in front of each statement so I don’t have to fill a clear set of ideas full of qualifiers.
The six basic emotions are analogous to the six types of taste. This is because emotions are the anticipation of eating. The best example is the correspondence between happiness and sweetness: the feeling of happiness corresponds to an expectation of eating high-calorie foods, due perhaps to finding a bush full of berries. This would arise from pure, repeated associations between the event and the food—after many instances of finding a berry bush and then tasting sugar, a Pavlovian association is formed between the berry bush and the expectation of eating sugar. After many generations, this mental trait could be iterated into recognizing much more complex events presaging food security, like receiving applause from a large group of people. It’s unlikely that an individual homo sapiens who’s being applauded one day will starve the next day, because common resources are apportioned according to status among hypersocial hominids. It follows that emotional mirroring would arise in hypersocial species as another Pavlovian association, given that the individual generally eats when and what the group eats.
Here are my best guesses as to the correspondences, with more likely ones toward the top:
Sweet -> Happy
Bitter -> Sad
Sour -> Disgust
Umami -> (Absence of) Fear
Astringent -> (Absence of) Anger
Salty -> (Absence of) Surprise
This correspondence could be extended beyond all reason by associating the emotions with neurochemicals that have large effects on behavior. Being a shameless and reckless sort of internet person, my guesses follow (again in order from most likely to least):
Happy -> Dopamine, endorphins
Anger -> Adrenaline, endorphins
(Absence of) Fear -> (Absence of) Cortisol
(Absence of) Surprise -> (Absence of) Adrenaline
Disgust -> Melatonin
Sad -> Serotonin
These guesses could undoubtedly be improved with a tiny bit of reading, but it’s already past my bedtime. Anyway it’s a fun set of ideas, take ’em for a spin and see how they hold up.