In the pop idiom, there appears to be a significant pattern of successful pop songs having high-pitched male vocals.
Bruno Mars, Michael Jackson, almost all rock songs (FOB, All American Rejects, Red Jumpsuit Apparatus, etc).
Put any of those vocals 1 octave down and it wouldn't be as catchy.
Is there something about the way humans naturally perceive sound that contributes to this pattern?
As commented by @Lee White,
While the perception is indeed subjective (not everybody prefers high voices), this question is about a very clear pattern that may have a scientific explanation. You could ask the same question about instruments: why is the first part generally played by the soprano violins and not by the double basses? Why are there so many more guitar solos than bass guitar solos?