This originally appeared in an article under the science section of the Guardian online, and I just plain couldn't let it go by.
Evidently, Metallica, as well as Samuel Barber, Nine Inch Nails and Tool, were played in 30 second bursts for a group of monkeys, at which point their reaction to the music was logged and chronicled. (The actual point of the study was to examine the effects of monkey-sound-inspired music on monkeys. Make your own joke here.)
To make a long story short, the only "human" music that had any appreciable effect on the cotton-top tamarins (like the Whitesnake-fan-simulacrum featured above,) was Metallica's "Of Wolf and Man." Oddly enough, and counter to the reaction of most fraternity brothers from the early to mid nineties, the song had a calming effect on our more primitive distant evolutionary cousins.
There are legions of Lars Ulrich/Metallica fans/Black album jokes to be made here. So many, I can't focus on just one. Leave your submissions in the comments.
I also really, really hope that British taxpayer money wasn't spent on this study.