Given our brain’s plasticity, we know that our online habits continue to reverberate in the workings of our synapses when we’re not online. We can assume that the neural circuits devoted to scanning, skimming, and multitasking are expanding and strengthening, while those used for reading and thinking deeply, with sustained concentration, are weakening or eroding. In 2009, researchers from Stanford University found signs that this shift may already be well under way. They gave a battery of cognitive tests to a group of heavy media multitaskers as well as a group of relatively light multitaskers. They found that the heavy multitaskers were much more easily distracted by “irrelevant environmental stimuli,” had significantly less control over the contents of their working memory, and were in general much less able to maintain their concentration on a particular task. Whereas the infrequent multitaskers exhibited relatively strong “top-down attentional control,” the habitual multitaskers showed “a greater tendency for bottom-up attentional control,” suggesting that “they may be sacrificing performance on the primary task to let in other sources of information.” Intensive multitaskers are “suckers for irrelevancy,” commented Clifford Nass, the Stanford professor who led the research. “Everything distracts them.”