Katy Perry Reveals Secret Formula For Single Success: 'The Goose Bump Test'

Perry says she knew 'Unconditionally' would be a hit because hit 'an emotional chord.'

When Katy Perry first previewed songs off her Prism album to journalists in New York, she singled out "Unconditionally" as her favorite track.

Why? Because it passed the "goose bump test."

"There's this test that I do in the studio, after a song's complete and you've tracked some vocals. It's kind of like the goose bump test. If, every time you hear it, it gives you goose bumps, it's hitting a chord inside of you that's really important," she explained after premiering the "Unconditionally" video on MTV. "It's an emotional chord inside of you. I love this song because not only can it be a romantic, intimate song, but it can be about the type of love that a mother has when she sees her first child, or best friends or partners ... It's a transcendent love, it's not just relationship status."

And that idea of going deeper than superficial status updates was important to Perry from the first moment she sat down to write "Unconditionally." After all, she'd recently returned from a UNICEF-sponsored humanitarian trip to Madagascar, and with the memories still fresh in her mind, she decided to write a song that explored what it meant to love truly, honestly and purely.

"I was kind of inspired by the love that I saw ... we'd go in these cruisers up the mountain for two or three hours, to the middle of nowhere, to check out these schools that they'd built," she said. "We live in such a world that is run by social status and material possession, and it can get really overwhelming and tiring to keep up with that — People are actually turned on by the amount of likes they have; it's crazy that our minds think that way these days.

"And so I went to the top of this mountain, I saw all these children, and the love that they had towards each other, they had no idea what Twitter or Facebook or any of that stuff was, they didn't care about it," she continued. "It was this unconditional love between all of them. It was that kind of pure love that's unaffected by the trends of the world."

And that message elevates "Unconditionally" beyond mere single status to Perry. With "Roar" still riding high on the Billboard Hot 100, she's less concerned with raising awareness of Prism as she is raising awareness of one's self.

"In the bridge [of the song], it goes 'Acceptance is the key to be truly free, will you do the same for me?' And there has to be a lot of acceptance these days," Perry said. "I just hope it strikes that same chord with people as it did with me; it hits them like 'Oh, I want to feel that love too.'"