An ‘auditory illusion‘ has gone viral after blowing the internet’s minds, as the audio in the clip isn’t actually getting higher in pitch, despite what it sounds like.
In the video, text tells us: “This is an auditory illusion. The sound isn’t actually getting higher, but your brain thinks it is – which is why you’re probably thinking…”
The camera then cuts to a handwritten note that the video began with, which reads: “There’s no way this is a loop.”
Clever, eh? Well, clever and completely baffling, of course.
In the caption, McBride explains that it’s all down to something called the Shepard Illusion, which is named after America cognitive scientist Roger Shepard.
Essentially, it sounds like the sound is continuously swelling, but as the clip somehow lands back at the same point it began with – as you’ll notice if you play it on loop a few times – that’s not the case.
McBride told LADbible: “In technical terms, a Shepard Illusion is the superposition of sine waves separated by octaves. In nontechnical terms, it’s the musical equivalent of a barbershop pole – as the higher note fades out, your ear ‘switches’ to a lower note.
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“I’m fascinated by the way the human brain works (or doesn’t)! I’ve even done a whole series of videos on cognitive biases – basically, the ways our brains malfunction.”
Offering a bit more of an explanation on TikTok, McBride said it was the same as the continuously falling corkscrew lines on a rotating barber’s pole, while another user commented: “It IS getting higher, but the pitch you hear is actually 2 octaves of the same note.“
According to Illusions Index: “What is actually happening is that the very same sequence of eight complex tones is being played over and over again.
“The repetition of the same octave being played creates the illusory experience of a continuous ascent or descent.
“The illusion is created because each tone is composed of many pitch frequencies that are carefully crafted to create ambiguity.
“Thus, one element of this illusion is that each tone is ambiguous and can be heard as either a higher or a lower sound depending on the context (which consists of the tones that were played before it).”
While there’s a perfectly reasonable excuse for the phenomenon, that’s not to say people don’t feel uncomfortable.
One person commented on the TikTok video: “I feel like I’m glitching when I listen to this.”
Another added: “I’ve been here for five minutes, it keeps getting higher!!!”
A third said: “I just listened to it for 3 hours straight and now the glass on my phone is shattered.”
Someone else wrote on Twitter, where it also went viral: “I feel like this is 2020 in audio form.”
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