Preliminary evidence for selective cortical responses to music in one-month-old infants [video]
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NANCY KANWISHER: So people have puzzled for a long time why humans have music at all. Darwin wrote about what a mystery it was that all human societies have music. Because as he pointed out, it's not like vision, or language, or speech, which all have obvious adaptive value enabling us to stay alive and thrive. Why don't we have music it's totally not clear.
My lab looks at the functional organization of the adult brain. And we found lots of regions that are engaged in very specific mental functions. From face recognition, to understanding language, to perceiving music. And so we wondered for years how all that stuff gets wired up in development. And how it knows where to go in the brain.
HEATHER KOSAKOWSKI: My name is Heather Kosakowski. I'm a post-doc at Harvard working with Randy Buckner. But before that, I was at MIT where I was a graduate student working with Rebecca Sacks and Nancy Kanwisher. And I studied human event brains. Most of the studies that have been done using fMRI or fNIRS haven't used well matched acoustic controls. So that's what we wanted to do here.
NANCY KANWISHER: So Heather Kosakowski is just an amazing force of nature who has unbelievable skills in scanning infants. And for this study, she scanned an incredible 45 infants after inventing her own infant scanning coil. Infant headphones. This was not an easy experiment to run.
HEATHER KOSAKOWSKI: And then we created a whole new stimulus set of speech and music sounds where we hired a bunch of musicians, and some moms to come in and record for us. We also used a model matching algorithm developed by Sam Norman Haignere to create model matched stimuli for the music and speech sounds. The model matched stimuli were matched on the spectral temporal properties of the original intact music and speech stimuli. And we hypothesized that if infants have a selective response to music, then the music response should be greater than both speech and the spectral temporally matched stimuli. Similarly, we hypothesized that if infants have a speech selective response, they should have a greater response to speech than to music or the spectral temporally matched speech stimuli.
NANCY KANWISHER: It was enough of a surprise a few years ago when we found music selective neural populations in adults. But now what Heather's shown is that those selective responses seem to be present by one month of age in infants. And that further suggests that you don't need a huge amount of experiential training to wire up that selectivity. It's ready to go, and it's present really early.
HEATHER KOSAKOWSKI: And so that will influence a lot of theorizing about how music perception develops. And I think a lot of people that are interested in music perception and music and development are going to be very excited by these results. A caveat of these results is that this is the first time somebody has found such strong music selective responses in babies so young. And so these results are going to need to be followed up, and confirmed, and explored further.
Dr. Heather Kosakowski and Prof. Nancy Kanwisher describe their latest journal article being published in Developmental Science regarding a study of selective responses to music in infant brains.
https://onlinelibrary.wiley.com/doi/10.1111/desc.13387
Research Highlights:
- Responses to music, speech, and control sounds matched for the spectrotemporal modulation-statistics of each sound were measured from 2- to 11-week-old sleeping infants using fMRI.
- Auditory cortex was significantly activated by these stimuli in 19 out of 36 sleeping infants.
- Selective responses to music compared to the three other stimulus classes were found in non-primary auditory cortex but not in nearby Heschl's Gyrus.
- Selective responses to speech were not observed in planned analyses but were observed in unplanned, exploratory analyses.
Abstract:
Prior studies have observed selective neural responses in adult human auditory cortex to music and speech that cannot be explained by the differing lower-level acoustic properties of these stimuli. Does infant cortex exhibit similarly selective responses to music and speech shortly after birth? To answer this question, we attempted to collect functional magnetic resonance imaging (fMRI) data from 45 sleeping infants (2.0- to 11.9-weeks-old) while they listened to monophonic instrumental lullabies and infant-directed speech produced by a mother. To match acoustic variation between music and speech sounds we (1) recorded music from instruments that had a similar spectral range as female infant-directed speech, (2) used a novel excitation-matching algorithm to match the cochleagrams of music and speech stimuli, and (3) synthesized “model-matched” stimuli that were matched in spectrotemporal modulation statistics to (yet perceptually distinct from) music or speech. Of the 36 infants we collected usable data from, 19 had significant activations to sounds overall compared to scanner noise. From these infants, we observed a set of voxels in non-primary auditory cortex (NPAC) but not in Heschl's Gyrus that responded significantly more to music than to each of the other three stimulus types (but not significantly more strongly than to background scanner noise). In contrast, our planned analyses did not reveal voxels in NPAC that responded more to speech than to model- matched speech, although other unplanned analyses did. These preliminary findings suggest that music selectivity arises within the first month of life.
Examples of the stimuli used in the experiment are available here: heatherkosakowski.com/stimuli/
All stimuli, code, and data are available for download here: https://osf.io/8ty34/