As the world begins to make amends from all the arguments caused by the “Yanny vs Laurel debate”, a new study has sought to understand another way in which our ears can play tricks on us (it definitely said Laurel, by the way).
If you repeat a short phrase over and over again, you’ll notice it starts to gain a rhythmic quality, almost as if it’s being sung. Researchers call this phenomenon the “speech-to-song illusion” and it could be used to understand how we process language, as reported in the journal PLOS ONE.
"There's this neat auditory illusion called the Speech-to-Song Illusion that musicians in the '60s knew about and used to artistic effect – but scientists didn't start investigating it until the '90s," explained lead author Professor Michael Vitevitch, chair of psychology at the University of Kansas.
"The illusion occurs when a spoken phrase is repeated – but after it's repeated several times it begins to sound like it's being sung instead of spoken."
You can listen to this effect for yourself in the audio clip above. It features an experimental song created by composer Steve Reich in 1965, produced using only an audio clip of a preacher shouting "It's gonna rain!" When you first hear the three words, it sounds like a normal phrase, however, it quickly begins to take the form of a rhythmic song.
To figure out why this happens, the researchers gathered 30 of their students and put them through a series of listening experiments. They were shown six different sets of words, each with different numbers of words or syllables. They even tried out one variation with Spanish words on a group of non-Spanish speakers. The participants were then asked to rate the different phrases in terms of how much they sounded like a song. You can listen to one of the audio clips in the player below.
The aim of the experiments was to test the theory that we detect and process speech using "word nodes" and "syllable nodes". The experiment showed that our brains effectively get “tired” of hearing the same word node over and over again, however, we continue to detect the syllable nodes. Since syllables carry the rhythmic information of language, yet we no longer hear the information content of the words being spoken, the sound transcends into a songlike state.
According to the researchers, this is why we tend to hear different things after listening to the “Yanny/Laurel” clip over and over again.
"You've got word detectors and syllable detectors and, like with lots of things in life, as you use them they're going to get worn out – like your muscles. As you use them, they get tired," added Vitevitch. "Like with muscles, you have a type of muscle for short bursts of sprinting and also muscles for endurance, like running a marathon. Word nodes are like sprinting muscles, and syllable nodes are like endurance muscles."