If you were given the chance to give full attention to two (or more) things at once, all the time, would you do it? 

From Distraction, by Bruce Sterling:

"The deal is this:  that old man was thinking of two things at once."

"What do you mean?" Kevin said.

"I mean that it's a neural hack.  He was fully aware of two different events at the same moment.  He didn't let that little kid hurt himself, because he was thinking about that kid every second.  And even though he was carefully working that hammer and chisel, he wouldn't let that bottle overflow.  He didn't even have to look at that bottle to realize it was full.  I think he was counting the drops."

"So it's like he's got two brains," Kevin said slowly.

"No, he only has one brain.  But he's got two windows open on the screen behind his eyes."

"He's multitasking, but with his own brain."

"Yeah.  That's it.  Exactly."