The brain is capable of "multitasking" far more complex than any computer is. And the capability can be ennanced by practice. I spent a couple years as a PBX operator in a rather large hospital. I got so I could juggle six or eight
calls, remembering who the callers were, who they were calling, and the phone numbers needed without having to consult any list. I would be a miserable failure at it now.
My recent memory is a travesty of what it used to be.