The Shallows: What the Internet is Doing To Our Brains, by Nicholas Carr. W. W. Norton, 2010.

Brains are plastic, and make and erase connections based on need and use.

Reading has changed from puzzlingoutwordsandmeaningwithoutbenefitofspacingandpunctuation at the dawn of writing to consuming headlines on the Internet. This has changed the way our brains work to the point where we can no longer concentrate for more than a few minutes at a time.  Reading a longer work from beginning to end is now a difficult task, because our brains expect to be interrupted often. In other words, we are now consuming a long tail of disparate information pieces, but unable to explore it in enough depth to engage our brains in real thought about any of it.

Do you believe this? I better go online and check it out. BRB.

So as software gets smarter and returns results related to what we're looking for, two things happen: 1. We stop thinking, because the software does that for us (think: point-of-need help, tailored internet search engine results,) and
2. we never see the other results, so therefore they don't exist - or, at any rate, are lost to us. The software filters what we see, based on prior searches, and our field of view gets narrower and narrower.

Carr's work is rife with references to research, and there are more than 30 pages of citations at the end of the book. Whether you agree with him or not, the evidence is compelling for his description of a major change in the way people interact with technology and the Internet: "As we come to rely on computers to mediate our understanding of the world, it is our own intelligence that flattens into artificial intelligence." Scary.