Surprisingly, your brain is busier talking with itself than doing anything else! 

Your brain is busy! For example, over a billion messages are sent to it every second from your retinas, the light to electricity covers in your eyes. The body sends it 100 million messages per second dealing with movement, feeling, posture, etc. And we haven’t mentioned hearing, smelling, and tasting messages. How can the brain handle all this information? Answer: it doesn’t. Instead, our brains have a filter called the reticular. In the picture it is not labeled but is located just behind the Pons and is about the size of your little finger. The name comes from a Latin word rete, meaning ‘net.’ It is named this probably because it looks like a net but also, perhaps, because it works like a net in the brain. The reticular actually tells you to see what you want to see, to hear what you want to hear. It works like this.
When you decide something is important, the reticular activating system will allow information relating to that something into your brain. Other information is filtered out as unimportant. You might have noticed this, say, when you were interested in buying something. Let’s imagine you want to buy a green van. Surprisingly, all around you are suddenly a multitude of green vans. Other green cars, and other colored vans are not even noticed. Or try this: name all the red objects in this room. Suddenly your reticular filters out all objects of other colors but send on to your brain red objects. Apart from the work of the reticular, your brain would be bombarded with a vast quantity of useless information and it would be too busy to concentrate on what is important. But what you view as important is up to you.
The two examples above deal with things that are morally neutral. But the reticular can be taught to allow good or evil to pass to the brain as well. As Christians, we are commanded to train our reticular to allow good things in, and filter out evil things. We are to be “wise unto that which is good, and simple concerning evil.” (Romans 16:19) That is, we are to notice, concentrate on, learn about what is good, but we are to shun things that we discern to be bad. This also works in our relation to others. “Love covers a multitude of sins” (1 Peter 4:8) in the BT (Brain translation) might read, “Train your reticular to filter out the faults in others out of love for them.”
Our brains are marvelously designed! God has given them a wonderful filtering mechanism that we can control. Today when you read the Bible or hear the preached Word, remember that it is far more important than the distractions that might try to steal your attention.