I'm not really sure that it's accurate to state that multi-tasking assumes that we're active at numerous activities at one at the same time. I'm more inclined to think that it only suggests that at any given time there are so many noteworthy events taking place around us that we're simply incapable of limiting ourselves to one of them. What, after all, could be duller than someone who's actually able to attend to one particular task when all around him or her so many interesting things are taking place?