Super Man-Like Hearing Abilities

The other day, I noticed something interesting -- our brains have the ability to filter out noise interference. My ThinkPad speakers aren't very powerful. When I decided to listen to some music while riding in the car the other day, the speakers seemed pitifully mute. The noise of the car greatly overpowered the sound of the speakers.

I left the music on despite this, and about 20 minutes later, I realized that I could hear my music just fine; I hardly noticed the noise of the car. Two things are true here -- the car didn't get any quieter during the ride, and my music didn't get any louder. This indicates to me that my brain selectively filtered out the noise of the car, and allowed me to better hear the music coming from my ThinkPad.