Hi folks. I'm brand new here and found this topic interesting. I'm not sure if the folks here do any sort of formal introductions, but I think my responses to this thread will tell enough about me in the way of an introduction.
1) It's really not likely there were changes in synaptic contacts after just three hours of music listening. That sort of plasticity really just doesn't occur in such short time frames and with just one exposure to a stimulus. Besides, that would be a huge leap to suggest any short-term behavioral change has anything to do with synaptic remodeling.
2) There are people who are always trying to argue classical music is better than heavy metal for all sorts of reasons, usually because they think heavy metal has some sort of satanic message hidden in it. I happen to enjoy both and find more commonalities than differences between the two types of music.
3) As for concentration and music, yes, music is a distraction, but it's all a matter of how you look at it. The reason you can focus better on your work while listening to music is that you have a single, intentional distraction that helps drown out all the other distractions. Think of it as white noise. I too find it difficult to focus without some sort of music on in the background. The more seriously I need to concentrate, the more driving and loud the music needs to be. Heavy metal, classic rock, some modern country, and classical music written for a full orchestra are the sorts of things that keep me going. My PhD dissertation was written to Dio, Ozzy, Clint Black, and Pat Benatar, among others. So, at least from my experience, it hasn't been harmful. On the other hand, I have run into the problem where it's harder for me to stay focused when there isn't any music playing, mostly because I start to notice all the other distractions around me. Since I'm well beyond the test-taking stage of my life, it's not much of an issue anymore. If I need to really concentrate on something, I can just close my office door and plug my earphones into the computer to play my music. I know I've really been concentrating when I tune out the music too -- or when I suddenly realize I'm working in a dark office because the sun has gone down and I didn't notice to turn on the lights while focused on the computer screen.
4) The point about the music not being on when you're taking your tests is a good one. I'm not sure if it has been formally studied or is just anecdotal, but there are claims that you'll perform best when the testing environment is more similar to your studying environment. I think it has to do with the associations you make with your environment. Memory works in funny ways. You know how a certain smell will suddenly make you remember something you once associated with that smell before? Sort of like that. That's why it's recommended you make your study environment as similar as you can to your testing environment. So, while you may find your creative side is inspired to write papers with the music on, when you're doing the hard-core studying for a test, turn the music off, sit at a desk, clear away all the extra clutter, etc. Of course, you'd do better to keep up with the studying all along than to cram at the last minute, but we all have done the last minute cramming session at one time or another.
