The redirection of our mental resources, from reading words to making judgments, may be imperceptible to us—our brains are quick—but it’s been shown to impede comprehension and retention, particularly when it’s repeated frequently. As the executive functions of the prefrontal cortex kick in, our brains become not only exercised but overtaxed. In a very real way, the Web returns us to the time of scriptura continua, when reading was a cognitively strenuous act. In reading online, Maryanne Wolf says, we sacrifice the facility that makes deep reading possible.
