Liberals go here. Conservatives go there.

When I walk the dog in my neighborhood, I meet a lot of people. They don’t all look like me but — according to Bill Bishop in The Big Sort — they probably think like me. Bishop argues that we’ve sorted ourselves out less along ethnic lines and more along religious, political, and philosophical lines. We tend to live with and talk to people who agree with us. Bishop argues that’s bad for our country. It tends to exacerbate our differences. We think everybody thinks like us because we only speak to people who think like us. Anybody who doesn’t think like us must be a small group of weirdos who can safely be ignored.

Sorting ourselves out may also be bad for us as individuals. According to recent research, one of the best ways to keep the brain stimulated — and to avoid dementia — is to read or listen to contrary points of view. If we only listen to sources we agree with, we’re simply reinforcing existing pathways in the brain, not creating new ones. What does that have to do with the Internet?  The Internet makes it much easier to find and consume only sources that we agree with. In the old days, we would read the family newspaper and be exposed to multiple points of view on the editorial page. With the Internet, it’s much easier to isolate ourselves in an echo chamber.

So, will the Internet cause dementia? It may already have. Watch the video.