* one (psychological) guess is that social conflict causes misophonia: mealtimes are one of the more socially intense situations in life, and so suppressed family conflicts may show up as irritation with eating sounds rather than with the person making them (who is the real object of negative emotions) – this suggests that misophonia is displaced anger.
* another (psychological) guess is that unhelpful thinking habits – possibly related to OCD or to obsessive compulsive personality disorder (which is different to OCD) – lead to misophonia: if you think “That person shouldn’t be making those sounds” you will become increasingly angry when they do continue to make “those sounds”.
* a neurological guess is that a conditioned reflex can form very quickly if a person happens to (say) cringe when hearing a sound (see above for the idea of mealtimes being stressful). Once a person is involuntarily cringing – or performing some other muscular “twitch” – whenever they hear a particular sound, they become angry at the source.
* another neurological guess is that misophonia is a form of synesthesia – an unusual neural connection between parts of the brain normally not connected. While common forms of synesthesia are unusual connections between sight and sound (sounds or words may “have” specific colors), it is possible to have (say) sounds connected to the flight or fight centre of the brain, causing the person to experience anger when they hear a certain sound. Some people experience pleasure at certain sounds (“ASMR” – )
* an audiological guess is that misophonia is connected to tinnitus – people with tinnitus often have misophonia.
* another audiological guess is that misophonia is caused by abnormalities in the ear itself, say something related to or a bit like .
* a genetic guess is that misophonia is caused by genetic factors. The gene reesearch organisation 23andme has found a linkage between misophonia and a pair of nucleotides which might affect neural functioning. The finding does not amount to a complete explanation, however, merely an interesting statistical correlation. In other words, some people may be more likely to acquire misophonia than others, but one or more of the above guesses, or maybe some other factor(s), are involved as well.
I have heard health or research professionals give every one of those guesses, more or less. Basically, misophonia falls at the meeting place of audiology, neurology, and psychology. The real research has only been going on in the last couple of years.