Step-by-step explanation:
Heavy Metal "music" impacts negatively the long term memory, if at least the ability to access it.
while harmonic music has no blocking effect or maybe even strengthens the long term memory and the ability to access it.
here 3 remarks.
first 2 scientifically from psychology : memory works mostly associative. that means brains do not store absolute information like a digital computer, but always in combination and association with other pieces of information. if there is nothing else to remember (like a more or less random pattern of sound effects for that the brain cannot find a rule or concept for), there are no associations with presented pieces of information, and the storage and access to it is much harder and restricted.
and - loud crashing and seemingly random noise triggers the panic mode in our brains. and panic is the mode favoring pure instinct and suppressing cognitive functions.
and finally, personally, it just confirms what I literally feel when listening to such music : it destroys at that moment any ability to keep a straight thought, prolonged exposure gives me the feeling that something gets broken inside my brain and thought processes.
I suspect that this is exactly the feeling that the fans of this kind of music are after (kind of like most drugs), but I am not surprised that there actually is something broken in the brain (again, as with drugs).
