I think the author tries to capture the counterpoint: that much of the effect is due to the sheer volume of text. From the article: "...we would have to accoun

I think the author tries to capture the counterpoint: that much of the effect is due to the sheer volume of text. From the article: "...we would have to account for the quality of reading too, as much of it involves skimming and darting around the page. But the sheer quantity matters...We are so used to our screens bombarding us with text — news, tweets, emails — that we are almost surprised to discover that the walls around us have nothing to say. The sudden absence of words — the evaporation of the sense of control they give us — feels disorienting. "