The Effect of Multitasking on Listening

Just when the radio industry is pushing its hardest to get radios on popular mobile devices like iPhones, iPods (other than Nano) and iPads, there is some academic debate bubbling under that indicates multitasking is bad for people.

I heard a fascinating NPR discussion a few weeks back on the deleterious effects of doing more than one thing at a time and my ears perked up.

Why not?