You might enjoy Kevin Simler’s review of Why Do People Sing?: Music in Human Evolution. It’s a beautifully written essay offering some speculative and surprising answers I don’t want to spoil.
Re: predictive error explanation: You might say that a good music piece needs the right balance of familiarity, emotional impact and surprise even when you are listening to it on repeat.
Hopefully before the end of the month! More than a half of the applications were submitted only over the weekend, so there’s a lot to evaluate.