It is a load of Hogwash, most creatures (actually can’t think of any that don’t) Multitask... there definition of multitasking is loaded...

Just being alive is multitasking, I can breathe, chew gum, type on the computer, listen to music, notice the air-con kicking in, etc, etc, etc ,etc all at the same time.
Just because I can't write an essay with pen and paper and read a totally unrelated news article on the computer screen does not mean I "don't pay attention"