Do you know what makes a song popular? That is to say, how does a song reach the top of the charts? What I'm asking is, why do some songs sell better than other songs? Well, the answer is in my question: repetition.

"What’s been shown in psychology is that people like things that they're more familiar with," Joseph C. Nunes, professor of marketing at USC Marshall School Of Business told MTV News. "And so there’s something called a mere-exposure effect, which means if you become familiar with something, if you’ve been exposed to it before, it tends to increase your liking."

Nunes dug into that idea in a recent study of music -- specifically lyrics -- and found that songs that feature repetitive lyrics enter the Billboard charts higher and climb to #1 faster. "You can think about in the olden days when people used to pay for play at radio stations -- if I can get you to spin my record and people to hear it a number of times, you know they're going like it more than songs they haven’t heard," he explained. "[We took a] single song and said, 'Well is there this familiarity effect, this repetition effect, within a certain song? What if the song is more repetitive, and hence your hearing the song [once could] do the same thing that hearing a song over and over again does. That's when we started saying, 'Hey lets code these songs according to how repetitive they are and see if that has an effect on which songs get to #1 versus those that stay at the bottom.'"

As part of his study Nunes examined not only all 1,029 songs that reached #1 on the Billboard Hot 100 chart since its inception, but also 1,451 songs that hit the chart but didn't climb above #90. These songs were then analyzed to see how often the chorus was repeated -- as well as how many times individual words were used. The results? Those songs with more repetitive choruses were more likely to take off. No wonder "Macarena" was able to sit at the top of the charts for 14 weeks -- the chorus crops up like 10 times.

Nunes' study only goes up until 2012, though -- so what about today's hits? What fits within his formula now, and what can we expect to take off?

"Taylor Swift is a pro at this right now," he said. "Her songwriters have figured this out. [Rachel Platten's] 'Fight Song' is pretty repetitive. And 'Worth It' -- oh my God, Fifth Harmony. I think whoever wrote 'Worth It' for them nailed it. [Mark Ronson's] 'Uptown Funk' is another one."

"[Ellie Goulding's] 'Love Me Like You Do' is down now, but my prediction would be the more popular ones and the ones that make it ultimately to number one will be those that are more repetitive," Nunes added. "I mean that’s what our data is telling us. [Charlie Puth's] 'Marvin Gaye' is repetitive too -- it's #48 now -- but I wouldn’t be surprised if that goes higher."

So, music folks, what can you take away from Nunes' study? "Past performance is not an accurate predictor of future performance," he warned. "[But] I would say... if I were going to write a song I would keep it simple and repeat the chorus at least six of seven times. If your goal is to get other people to sing along and to connect with the most people possible, I would say keep it repetitive."

You can say that again. I know, I hate me, too.