In 80 clinical trials, Dr. Glenn Wilson, a psychiatrist at King's College London University, monitored the IQ of workers throughout the day. He found the IQ of those who tried to juggle messages and work fell by 10 points -- the equivalent to missing a whole night's sleep and more than double the 4-point fall seen after smoking marijuana.Hmm. In Delivered from Distraction, Hallowell claims that modern fast-moving communication contributes to something he regards as "pseudo-ADD." He suggests that reducing access to TV, video games, and internet can improve the symptoms of this.
(In a similar vein, I guess this is Turn Off The TV Week. I need Turn Off The Web Week, though.)
link from patrissimo