That figures realy getting around at the moment. The way I see it is speaking to people or writing takes a toll on your brain, engaging in passive activities like reading or watching tv is replenishing your IQ in some way, resting the creative parts of your brain as well as giving you new information to assimilate into conversation. You then cash in these points in social activities and so forth.
So saying the internet makes you dumb, is like saying running makes you tired, stop going to the fucking gym.
Oh and MH, Heathen was a damn fine album, shame Bowie fucked up with reality.