Taylor Swift, benevolent overlord of the pop universe and enemy to streaming services, has built her career on a preternatural ability to generate catchy hooks. “Bad Blood” was released a little over a month ago, and you’d already be hard pressed to find anyone capable of hearing the line “‘Cause now we’ve got bad blood” without filling in the inevitable, chorus-punctuating “Hey!” Turns out that even haters who are gonna hate can’t help but succumb to Swifty’s songwriting technique, which relies on repetitive melodies and sneering chants.

Think of T Swift as a supremely talented and scientific minded breeder of summer-destroying earworm.

The French call earworms musique entêtante, or stubborn music, while the Italians go with canzone tormentone, tormenting songs, but researchers don’t have an exact term for the phenomenon of “stuck in my head.” Still, they’ve begun to understand their simple anatomy.

Earworms are usually very short snippets of songs, but once they’re in your head, they cycle and loop ad nauseum. They’re taken from songs with singable, simple, and repetitive melodies. That they have melodies is key here: Legendary neuroscientist Oliver Sacks and multiple other researchers have reported that verbal earworms are rare, whereas musical earworms are incredibly common, suggesting that stickiness has everything to do with musicality. A study on earworms led by Bucknell University professor of psychology Andrea R. Halpern points out that in these songs, “the end of a phrase triggers the opening for many cycles.” Enter Taytay and, looking back a bit, “Shake it Off.” That song has never been stuck in your head. Parts of it have been (and probably are now, sorry about that).

Think about TSwizzle’s other recent hits. Like “Bad Blood”, the core melodies of “Style”, and “Out of the Woods” consist of just a handful of notes (“Out of the Woods” is, literally, one note). Their choruses consist of a single melodic phrase that’s repeated several times, and then, in the final echo, the shape of the phrase changes slightly — just enough to give it a sense of conclusion. Then the cycle starts all over again.

In his Pop Music Masterclass series, Canadian musician Chilly Gonzales succinctly breaks down what makes “Shake it Off” so infectious. He applauds Taylor for her use of a distinct melody — in this case, the descending “Playas gonna play play play play play” — which she repeats and then, at the end of the chorus, “ties up with a bow.” He also points out her effective use of the “playground technique”: Her melodies are so strong that the instrumentals are unimportant. They’re singable whether or not the background music is playing, a quality shared by the most contagious of schoolyard chants.

A closer listen to “Bad Blood” just proves that Tay’s got this formula down to a science. The production on that song is both elaborate and unnecessary. 

Though she’s the reigning queen bee, a quick scan of other current chart toppers (the endlessly circular “Trap Queen”, the embarrassingly catchy “Shut Up and Dance”, and the infectious “Want to Want Me” shows other artists using the same technique to hook their listeners.

A 2011 study using fMRI scans implied that our emotional engagement to a piece of music is closely tied to our familiarity with it, and it makes sense that repetition leads to greater familiarity. In another fMRI-based study, researchers inserted silent gaps in familiar songs and found that test subjects involuntarily filled in those gaps by “singing” the song in their heads, providing a neural basis for the “obligatory nature” of earworms and suggesting that our brain’s memory systems have a big role to play. It’s also been suggested that musicians and people with compulsive tendencies might be more badly affected, perhaps because their brains are more likely to repeat musical phrases. Do not play Swift in a psych ward unless you want things to take a turn.

In his commentary in the journal Brain, Sacks discusses humans’ unique responsiveness to music and our brain’s vulnerability to what he calls “too-muchness”, an appetite for something that can never be fully sated. Musically speaking, the brain might continually loop song snippets as a way of trying to scratch that itch.

Whatever control we do have, it’s nothing the omnipresent Sweezus can’t rip out of our heads and replace with her inescapable, mind-controlling angelsong. If you’re one of the rare few who haven’t surrendered to her, research shows that “scratching the itch” — listening to the entire song to connect the offending fragments — might help. Then again, it might not.