“`html
In a realm teeming with competing noises, we frequently need to sift through substantial clamor to discern what’s most significant. This vital ability may come more naturally to individuals with musical education, according to researchers at MIT’s McGovern Institute for Brain Research, who utilized brain imaging to observe what transpires when individuals attempt to concentrate their focus on specific sounds.
When Cassia Low Manting, a recent MIT postdoctoral researcher collaborating with MIT Professor and McGovern Institute PI John Gabrieli and former McGovern Institute PI Dimitrios Pantazis, requested participants to concentrate on a specific melody while another melody played concurrently, individuals with musical backgrounds were, as expected, more adept at tracking the target tune. An evaluation of the brain activity of study participants indicates this edge emerges because musical education enhances neural mechanisms that boost the sounds they wish to hear while diminishing distractions.
“Individuals can perceive, comprehend, and prioritize numerous sounds around them that unfold on a moment-to-moment basis,” clarifies Gabrieli, who is the Grover Hermann Professor of Health Sciences and Technology at MIT. “This research uncovers the precise brain mechanisms that successfully process simultaneous sounds on a moment-to-moment basis and foster attention to the most crucial sounds. It also illustrates how musical education modifies that processing in the mind and brain, offering insights into how experiences shape the way we listen and concentrate.”
The research team, which also included senior author Daniel Lundqvist from the Karolinska Institute in Sweden, disclosed their open-access results on Sept. 17 in the journal Science Advances. Manting, who is now affiliated with the Karolinska Institute, mentions that the research is part of a continuous collaboration between the two institutions.
Surmounting obstacles
Participants in the study exhibited vastly divergent backgrounds concerning music. Some were professional musicians with extensive training and experience, while others found it challenging to distinguish between the two melodies presented to them, notwithstanding each one’s unique pitch. This inequality allowed the researchers to investigate how the brain’s ability to concentrate might vary with experience. “Musicians are particularly enjoyable to examine because their brains have been shaped in ways influenced by their training,” Manting remarks. “It’s an excellent model for studying these training effects.”
Nonetheless, the researchers faced significant hurdles. Studying how the brain administers auditory attention has been challenging, as using neuroimaging to observe brain activity reveals the brain’s responses to all sounds: those that the listener prioritizes, as well as those the listener aims to disregard. It is generally difficult to determine which brain signals were elicited by which sounds.
Manting and her colleagues tackled this issue with a technique known as frequency tagging. Instead of presenting the melodies at a constant volume, the loudness of each melody fluctuated, rising and falling at a specific frequency. Each melody possessed its distinct frequency, generating identifiable patterns in the brain signals responding to it. “When you present these two sounds simultaneously to the participant and record the brain signal, you can specify that this 39-Hertz activity corresponds to the lower-pitched sound and the 43-Hertz activity correlates specifically to the higher-pitched sound,” Manting elucidates. “It is very straightforward and very clear.”
By combining frequency tagging with magnetoencephalography, a non-invasive method of observing brain activity, the team could monitor how their study participants’ brains reacted to each of the two melodies throughout their experiments. While the two tunes were playing, subjects were directed to focus on either the higher-pitched or the lower-pitched melody. After the music ceased, they were questioned about the final notes of the target tune: did they ascend or did they descend? The researchers could complicate this task by bringing the two tunes closer in pitch and by varying the timing of the notes.
Manting employed a survey assessing musical experience to evaluate each participant’s musicality, and this metric had a clear impact on task performance: the more musically inclined a person was, the more effective they were at tracking the melody they had been instructed to follow.
To investigate differences in brain activity that might elucidate this, the research team developed a novel machine-learning approach to analyze their data. They used it to dissect what was happening in the brain as participants concentrated on the target melody — even, in some instances, when the notes of the distracting melody played simultaneously.
Top-down versus bottom-up attention
Their findings revealed a distinct separation of brain activity linked to two types of attention, known as top-down and bottom-up attention. Manting clarifies that top-down attention is goal-directed, involving a conscious focus — the type of attention listeners employ as they follow the target tune. Bottom-up attention, conversely, is activated by the characteristics of the sound itself. A fire alarm would likely trigger this type of attention due to its volume and abruptness. The distracting melody in the team’s experiments elicited activity associated with bottom-up attention — but this varied more in some individuals than in others.
“The more musically inclined someone is, the better they are at honing their top-down selective attention, and the lesser the impact of bottom-up attention,” Manting clarifies.
Manting anticipates that musicians utilize their enhanced ability for top-down attention in various scenarios. For instance, they might excel at following a conversation in a room bustling with background noise. “I would wager that there is a substantial chance they will be proficient at focusing on sounds,” she states.
She does contemplate, however, if a certain type of distraction might actually be more challenging for a musician to filter out: the sound of their own instrument. Manting plays both the piano and the Chinese harp, and she describes hearing those instruments as “like someone calling my name.” It’s one of many inquiries regarding how musical training influences cognition that she aims to investigate in her forthcoming research.
“`