> You then wonder why evolution haven't come up with this trick?
> What (if any) is the downside for a fly with a boosted PKM level?
> Too many irrelevant memories?
> Would you be able to boost PKM levels at times when you know that some
> important learning is going to take place, and then bring the levels down
> with the effect of keeping the important memories for a lifetime, but having
> less important memories fade in the usual way?
>> Lets return:
Because evolution, like invention is the birtchild of necessity. Just
because having an average memory wasn't causing Fruit Flies to die
young doesn't mean that "artificially" increasing that memory will be
to their disadvantage. Nature does know best, but sometimes she needs
a good kick in the ass.