My armchair-neuroscientist take: forgetfulness is an evolutionary necessity. If we remembered every detail of our lives (every pebble on every road, ever second of every day) then we would reach our brain’s total capacity in a single day, and it would take enormous amounts of calories to preserve all that information. So every living creature forgets.
Once we reach maturity evolution basically stops “caring about us” (that is an anthropomorphism)- our systems are left “on maintenance mode”, which in evolution’s case means “luck”. Some fortunate souls might preserve their natural memories until they reach 70 or 80, but most people don’t, and for some the “maintenance mode” comes super early, because biology isn’t exact.
That said, I also think that nature is part of it but nurture also plays a role. The human brain is incredibly flexible. You can partially overcome or at least delay the worst of your memory loses with the right environment, and you can also squander your natural gifts and succumb early with the wrong one.
Once we reach maturity evolution basically stops “caring about us” (that is an anthropomorphism)- our systems are left “on maintenance mode”, which in evolution’s case means “luck”. Some fortunate souls might preserve their natural memories until they reach 70 or 80, but most people don’t, and for some the “maintenance mode” comes super early, because biology isn’t exact.
That said, I also think that nature is part of it but nurture also plays a role. The human brain is incredibly flexible. You can partially overcome or at least delay the worst of your memory loses with the right environment, and you can also squander your natural gifts and succumb early with the wrong one.