Imagine opening a difficult book in a quiet room. The first page is dense. You read one paragraph, then reread it. Nothing “clicks” yet. Your brain is doing what learning often requires: spending effort before the reward arrives. Then your phone lights up. One thumb movement, and the situation changes completely. A joke, a message, a clip, a tiny social reward: all available instantly, all requiring almost no effort. The book has not become harder and, definitely, your intelligence has not disappeared. But the book now feels more expensive, because another activity nearby offers a much better bargain: reward now, effort almost zero.