In 2017 I published the last two papers from my dissertation research, so I thought I would take this opportunity to share a little bit about my research project and what I discovered, especially about rhythm.
I did my PhD at the Auditory Neuroscience Lab at Northwestern University with Dr. Nina Kraus. I set out to investigate how different types of musical experience affect everyday skills, such as the ability to stay focused, or the ability to understand what a friend is saying in a noisy restaurant. I recruited percussionists/drummers, vocalists and non-musicians from the Chicago area and ran a load of different tests in the lab, from computer-based tests, to various drumming tasks, to recording brain activity while my test subjects listened to different sounds.
One of my particular curiosities was about rhythm, which is why I included percussionists and drummers in the study - they were my "rhythm experts". Rhythm is interesting because the ability to keep track of musical rhythms relies on very precise timing inside the brain. And it turns out that this coordination within the brain - including the brain's own rhythms - is important for a lot of other things, such as paying attention and understanding speech.
Not too surprisingly, I found that the drummers and percussionists were better than the others at drumming - unfortunately that discovery wasn't enough for me to get my PhD...! What I also discovered was that the more accurately a person could play rhythm patterns (whether or not they had any musical training) the better they were able to understand speech in a noisy background. In other words, someone who did just a little better at drumming the rhythm patterns, would also do a little better at understanding speech in noise, and this was especially true with the more complicated rhythms. This is an exciting result because it suggests that being able to keep track of rhythm patterns in music may actually help you follow the natural rhythms of speech. Perhaps you've had that experience where the "shape" of a sentence seems to hang in your head for a moment before you figure out what the person actually said? Our brains process the sounds of language on many levels, and all these different clues help us make sense of what we hear - it seems rhythm may be an important piece of that puzzle!
I also found that the ability to do something quite simple, just tapping along with a metronome, was linked to attention skills. So the more consistently a person could tap the beat of a metronome, the better they scored on a standard computer-based attention test. The most interesting part related to a particular component of attention called "inhibitory control". Inhibitory control is all about dealing with conflicting thoughts and actions, and blocking out irrelevant signals. It is measured by looking at how well a person can "hold back" their response, especially in situations where they are all ready to respond. For example, in the computer test we use, the person must hit a button when they hear or see a "1" but not when they hear or see a "2". A person who keeps responding to a "2" by mistake would be considered to have poor inhibitory control. Now, in the music part of the experiment the participants weren't listening to 1's and 2's, instead they were listening to songs while I was recording their brain activity. Superimposed on the songs were contrasting sounds (this additional sound was described by some participants as sounding like a goose honk, so it was clearly not part of the song!). Sometimes these goose honks occurred exactly on the beat of the music, and sometimes they were slightly after the beat.
What I found was that the brain response to the honk was different based on whether or not the honk was on the beat. The bigger that brain difference was in the music test, the better the person did in a standard clinical test of inhibitory control. In other words, the more sensitive a person's brain was to whether the honk was "in time," the better their inhibitory control. This discovery fits nicely with other research suggesting that the ability to resolve conflicting information and control your responses accordingly is a major ingredient of music, and may explain why musicians are often better at these inhibitory control tests. Again, it seems that drummers and percussionists may be especially good at this, perhaps because their playing is all about the careful coordination of actions in time. A good drummer must not only know when to play, but also when NOT to play..!
This is a fascinating area of research and there is still so much to learn. In my current postdoc I am working with a neurosurgeon and studying how brain rhythms help to coordinate attention (more about that here). In the future, I am hoping to connect these areas of research by looking at rhythm and timing in ADHD. Many people with ADHD have difficulty with time perception, and for some that includes the kinds of rhythm tasks I have described here. Understanding more about this could provide important clues about how the brain's internal rhythms get disrupted in ADHD, and how we might be able to fix them - possibly using music.