Filters
We are constantly subjected to a barrage of sensory input. To save ourselves from being overwhelmed, the brain has to get rid of most of it. Well, it doesn't actually get rid of it. Rather, the brain pre-processes the input and if, after some evaluation, it decides it's something we need to know, the information enters into our consciousness.
That's how some people manage to live near airports. Most of us, if we hear an airplane flying low over our home, will drop to the floor and cringe. But people who are accustomed to the noise don't even notice it any more. They filter it out and, in a sense, they don't even hear it. It probably took them a while to learn this trick.
An Example of a Filter
Here's Bob at a very noisy party. He's about to perform a trick that most of us already know how to do with varying levels of skill. (I do it very poorly.) The trick is known as "The Cocktail Party Effect".
Bob has just heard somebody say his name, and even though everybody is talking loudly, it got his attention. I expect you've been in that situation yourself. A lot of people are speaking at once and suddenly you'll hear one word that interests you.
The Cocktail Party Filter is another example of the brain doing things in the background that we're not aware of.
Bob's Filtering System
Bob is a guy from Toronto who plays golf, which gives you an idea of some of the words that trigger his Cocktail Party Filter. Let's have a look at his filtering system...
Some notable features of Bob's filtering system include:
At this particular party, Bob heard somebody mention that there was a new golf course, named Shady Pines. Bob's filter was updated to listen for more details about this exciting new information. He does this without any noticeable effort.
You may have noticed something similar, yourself. You encounter an unusual word in a book, and a few days later you see it again. It seems like a strange coincidence — some people even claim it has something to do with ESP or synchronicity — but a more likely explanation is that for some reason the word stuck in your mind and now you're filtering for it.