Eating my lunch in Saint Paul's Mears Park the other day, I was accompanied by a bubbling brook and a Mozart concerto from the loud-speakers. It certainly made me feel relaxed and focused, but not a whole lot sharper.
This is because the whole "Mozart Effect" - that listening to Mozart would make children progress quicker, students study harder and everyone just a notch above-average - has been proven to be bunk.
But a new study out by researchers in London says "stop the music!" There is indeed a Mozart effect, just not quite what was once expected. Only non-musicians experience better cognitive skills (at mental rotation tasks) after listening to Mozart. Musicians notice no change because they're already more proficient in those tasks than those who don't make music.
So maybe you should take up those singing lessons afterall!
I don't know about the research on the effect of Mozart. As for singing lessons, they will cancel out any positive effects of listening to Mozart. Singing brings about premature senility by shaking up the brain pan too much with all that high resonance. Just take a look at the glazed over and incoherent stupor of a tenor after he's belted out a couple of high Cs. No further research is necessary.