It's a question that comes up time and time again: Are orchestra conductors really necessary? Plenty of concert purists argue that conductors are integral, and that skeptics just don't understand the importance of conductors' behind-the-scenes work. "Most of what a conductor does is not done in front of the general public," author and Grammy Award-winning conductor Leonard Slatkin tells the Los Angeles Times. "By the time you get to the actual concert, you've worked out pretty much what you want to do. It's really a matter of getting 100 musicians to think like one person."

And yet, the exact role of the baton-wielding maestro has been a point of contention for decades. The late Hans Keller, an Austrian-born musician and writer, was said to have called it one of the rare "phony" musical professions. Others criticize the position as being one of pure spectacle. 

A new study from the University of Maryland aims to the put the question to rest by analyzing whether the conductor leads the orchestra or the orchestra leads the conductor. In this experiment, researcher Yiannis Aloimonos and his colleagues installed tiny infrared lights at the tip of a conductor's baton as well as on the bows of violinists. While the orchestra played, infrared cameras captured every movement, which were then analyzed using mathematical techniques pioneered by Nobel-Prize winning economist Clive Granger. The scientists in this study theorized that if the movements of the conductor predicted the movements of the violinists, then the guy holding the baton was clearly in charge

"You have a signal that is originating from the conductor, because he is moving his hands and his body," Aloimonos tells NPR. "And then the players, they perceive that signal, and they create another signal by moving the bows of the violin appropriately. So you have some sort of sensorimotor conversation."

So what happened? It turns out the purists were right all along — the movements of the violinists were indeed predicated on the movements of the conductor. But that's not all: Researchers had two different conductors lead the orchestra. One was a veteran who directed the violinists with a firm grip, while the other was an amateur. In a blind listening test, music experts subjected to the two performances rated the veteran conductor's as undeniably superior.

"What we found is the more the influence of the conductor to the players," said Aloimonos, the more "aesthetically pleasing the music was overall."