May 17, 2018
Laura Dilley is associate professor in the Department of Communicative Sciences and Disorders. She also runs the MSU Speech Perception and Production Lab.
As someone who researches speech, hearing and language production, I found this week’s “yanny vs. laurel” audio clip fascinating.
There’s ongoing debate among researchers about how people hear two different words (or others). In my opinion, there are many reasons why someone might hear one word vs. another word.
A main reason for differences in perceptions of words involves differences among people’s experiences – both long-term – meaning over their lifetimes – and short-term — meaning in the last days, weeks or months, or even the last hours or minutes. Those long-term and short-term experiences have been shown in some cases to dramatically shape how our brains translate sound into meaningful categories of information.
Our early experiences – those that happen when we are babies – are particularly influential and important for how we translate sounds into meaningful information as adults. Our early experiences have such a big impact because during early infant development, our brains strengthen certain neuronal and synaptic connections, while we lose others – the “use it or lose it” principle at work.
For example, people who grew up in Japan listening to Japanese lose most of their ability to hear the differences between English “r” and “l” sounds, because these sounds map to one meaningful sound category in Japanese, which is part-way between English “r” and “l. That’s fine for speaking Japanese, because a person’s interpretations will be tuned to Japanese. However, it can be a problem for native Japanese speakers who want to become fluent speakers of English.
Other reasons why someone might hear one word vs. the other word include the dialect they grew up hearing or the individual people they grew up hearing. For example, the variety of English spoken by many African Americans has different statistical patterns of frequency than the variety of English spoken by many White Americans.
The specific mannerisms of pronunciation of my mother are different from the mannerisms of pronunciation by your mother or other people’s mothers. We know that babies can recognize differences in languages, dialects and individual talkers within days of birth, sometimes even while still in the womb, including being able to distinguish their own mothers from those of other mothers.
Most of the time, these differences in pronunciation don’t matter much for figuring out what someone is hearing because the context can help us figure out what word is being spoken. However, in cases where someone is deliberately trying to make a sound pattern that is ambiguous between two words or sound categories, our personal biases are revealed.
Our own personal perceptions are huge in auditory illusions such as the yanny/laurel effect. Often, peoples’ brains are able to pick up on the statistical patterns in what we are hearing — even when we’re not aware of these patterns.
Some people are better at picking up on statistical patterns than others. For example, individuals who are on the autism spectrum or who have autistic personality traits have been shown to be worse at picking up on nuances of pronunciation of sound than individuals who are more socially adept.
The yanny/laurel illusion “works” because the sound patterns are statistically “on the fence” between two categories for most people. People draw their lines between different categories in slightly different places, based on a lifetime of experiences, where sometimes those differences seem very small and inconsequential.
Context and word familiarity are also really important in this type of illusion. For example, someone who loves soft-pop music may be more likely to hear the “yanny” interpretation because of their love for new-age musician Yanni. Other people may be more likely to hear the “laurel” illusion because someone they know is named “Lauren” or because they are into gardening.
Although my first name is Laura, I still heard the “yanny” interpretation, and that doesn’t reflect my musical preferences or hobbies in any clear way. There is a lot we still don’t understand about these types of auditory illusions.