On the other hand, I have come across a fair few who used to daydream at work, too.
But yes, it seems that not having to concentrate on stuff immediately in hand releases memory for data that has remained dormant (and buried).
A bit like the Stack in (computer) programming terms. Or maybe "clearing the decks" (for action) is a better metaphor.
But what may be more interesting is that that old stuff is still "addressable", as it were (that is, still there, just waiting to be retrieved). But like archived data, sometimes it takes a while to bring it back to ready use.
