French scientists have uncovered an odd superpower triggered by tapping your finger to a rhythm – it can help you hear and understand someone talking to you in a noisy environment, such as a party or a busy cafe. While it may sound a little woo-woo, there is a reason for it.
Aix-Marseille University researchers hypothesized that prepping the natural rhythm of a brain by finger-tapping could help you then better "tune in" to speech. Previous research into the "rhythmic priming effect" has looked into various modes of delivery and its impact on speech – such as music in language comprehension and therapy for children with developmental language disorder (DLD). But its application in broader contexts is largely unknown.
"The motor system is known to process temporal information, and moving rhythmically while listening to a melody can improve auditory processing," the scientists wrote. "In three interrelated behavioral experiments, we demonstrate that this effect translates to speech processing. Motor priming improves the efficiency of subsequent naturalistic speech-in-noise processing under specific conditions."
In the first experiment, 35 participants each tapped a finger to different beats – slow, medium, fast – before having to take in a lengthy spoken sentence buried in intrusive background noise, noting down words they'd identified. The idea is that because speech has different natural rhythms among its syllables and words, priming your brain to tune into this pattern could help your brain process rhythmic language better.
The researchers found that there was much better comprehension of that noisy sentence after tapping along to a medium-paced beat, which equals about two taps a second, compared to the fast, slow or no-tap primer. This was the "lexical" or word rate, similar to speech, or around 1.8 Hz.
In the second experiment, which sought to find out if it was the tapping, the hearing of the beat or both that appeared to make a difference at this 1.8-Hz rate. The researchers found that, surprisingly, tapping – either on its own or along to a beat – delivered better speech comprehension, while just listening to a beat without a physical response was not as impactful. This suggested that "active" rhythmic priming was key.
Finally, a third experiment featuring another 28 participants analyzed whether saying a single word before exposure to the noisy (but yet unknown) sentence would improve sensory processing. Essentially, regardless of whether the word related to the sentence content, the act of saying it out loud appeared to improve the brain's listening skills. Again, hinting that the physical movement is the important aspect of rhythmic priming.
"These findings provide evidence for the functional role of the motor system in processing the temporal dynamics of naturalistic speech," the researchers wrote in the paper.
Overall, in controlled experiments, there was evidence of improved speech recognition in participants who performed some physical task prior to the listening activity. However, there were several limitations. Among those were that people who took part in the study were young, French-speaking adults with no neurological conditions; and previous studies have shown that rhythmic prepping may be linked to the rhythm of specific languages. More research is needed to determine if this priming has an impact on those who have difficulty filtering out background noise, such as people with hearing loss or ADHD.
The study was also purely behavioral and observational; the scientists propose that the mechanism involves the motor areas and the auditory dorsal pathway, but that remains a theory until brain imaging can support the findings. Nonetheless, the findings open the door to further study that could ultimately help in the areas of learning and rehabilitation.
And while more research is needed, this is at least one series of experiments you can safely perform at home. And as someone with ADHD-related poor sound filtering, any benefit would be a bonus.
The study was published in the journal Proceedings of the Royal Society B.
Source: Aix-Marseille University via Scimex
