It's a frustrating thing most of us have experienced.

大多数人都有过这种沮丧的经历。

A song gets stuck inside of your head, seemingly playing on a permanent loop.

你的脑海里总回荡着一首歌，这歌似乎还处于循环播放模式。

But what are the most difficult tunes to shift - and why do they get stuck in the first place?

不过你知道最洗脑的歌曲都有哪些吗？为什么一听见它们，你就无法忘怀？

Well, now you can find out - because researchers have developed a mathematical formula to explain the phenomena.

嗯，现在你能搞明白到底是怎么回事儿了——因为研究人员已列出了能解释该现象的数学公式。

The experts claim the formula sheds light on why some musical combinations are unforgettable - and in some cases, inescapable.

专家称该公式能阐明某些旋律令人难以忘记甚至挥之不去的原因。

These include Happy by Pharrell Williams , the Village People's YMCA and Queen's Bohemian Rhapsody and We are the Champions.

法瑞尔·威廉姆斯（Pharrell Williams）的《快乐》、乡下人（Village People）的《YMCA》、皇后乐队（Queen）的《波希米亚狂想曲》和《我们是冠军》都属于洗脑神曲。

According to the research by the University of St Andrews, the recipe for an earworm has five key components.

圣安德鲁斯大学（University of St Andrews）的研究人员称，制造抓耳歌曲需要满足五个重要条件。

These are receptiveness - how you feel about the song - predictability, surprise, melodic potency - how good the 'hook' is - and rhythmic repetition.

这五个条件即感受力（你觉得歌曲如何）、预见性、惊喜、旋律的影响力（抓耳的“钓钩”有多好）和有节奏的重复。

The exact formula was revealed as: Receptiveness + (predictability - surprise) + (melodic potency ) + (rhythmic repetition x 1.5) = earworm.

精确的计算公式是：感受力+（预见性 - 惊喜）+（旋律的影响力）+（有节奏的重复x 1.5) =抓耳歌曲。

Bede Williams, of the University's School of Philosophical, Anthropological and Film Studies, looked at, among other things, a study into the nation's top 20 earworms, commissioned by Heinz to promote their new #cansong TV advert.

该校哲学、人类学和电影研究系的比德·威廉姆斯（Bede Williams）受亨氏公司所托，查看了针对本国前20名抓耳歌曲的研究，以此帮助亨氏改进新的#罐头曲电视广告。

Bede, who is also research co-ordinator of the HARK project, which looks at our listening habits, said: "If you look at the songs which emerged from the research, they all have a distinctive rhythmic fingerprint - if we removed the melody they are recognisable by their rhythm alone.

比德还是“听”项目的研究协调员，该项目探究了人们的听歌习惯。比德说：“当你倾听研究项目中的歌曲时，你会发现它们都有独特的节奏，即使我们去掉旋律，你也可以单凭节奏辨认出那是什么歌。”

"If you think of the opening of 'We will rock you' or the chorus of 'Who let the dogs out?' you'd be able to identify the rhythmic hook that persists throughout each song independent of the melody.

“如果你回想一下《我们将震撼你》的前奏或《是谁放走了狗》的副歌，你就能辨认出贯穿于整首歌的节奏，它是独立于旋律之外的。”

"A significant aspect of a successful earworm is also down to a catchy lyric, of which we will all remember for different reasons."

“朗朗上口的歌词也是抓耳歌曲冲击热门的关键，我们会因为不同的原因记住这首歌。”