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by Julia Priest, M.S., M.Mus., for Perspectives, the journal of the Early Childhood Music and Movement Association, in press Spring 2010
Parents often ask music and movement teachers whether class
is beneficial for their newborns and young infants. Some parents tell us they
plan to wait “until the baby can really get something out of it.” What can we
tell them to support our intuitive conviction that they should come to class
“early and often”? This article will report on four recent studies that should
help early childhood music and movement specialists speak with evidence-based
clarity. For the sake of simplicity, we will honor the scientific convention of
calling a human being before birth a fetus,
reserving the terms infant and baby for the neo-natal period.
The twenty-first century studies described in this article
were designed to be more convincing than some of their predecessors by virtue
of being prospective (the researchers ran the experiment on people instead of
asking people to reconstruct and narrate past events from memory), randomized
(substantially similar subjects were randomly assigned to the control or
experimental groups, or else a single subject experienced the control stimulus
and the research stimulus in random order), and double-blind (there was a sham
stimulus; the statisticians didn’t know which data they were analyzing). We
will close with a synopsis of a foundational twentieth-century study.
“Foetal response to voice and music.” Australian and New
Zealand Journal of Obstetrics and Gynecology 2005; 45: 414-417, Al-Qahtani,
Noura H.
Despite the drumbeat of the heart, rush of blood, and gurgle
of digestion, the womb is quiet enough that the mother’s voice and other nearby
sounds emerge clearly. Dr. Al-Qahtani reminds us that scientists were observing
fetal response to external sounds as early as the 1920’s. However, measuring
the responses is always confounded by the fact that fetuses move unpredictably
and even their heart rates vary unpredictably. Statisticians have developed a
panoply of arithmetical tests to separate out spontaneous variations in the
data from variations that might be a response to the research stimuli.
Ten women whose pregnancies were at least 37 weeks advanced
participated in the study. Dr. Al-Qahtani played each fetus both instrumental
music and vocal sounds. She chose Spanish guitar music because, she said, it
comprised a large range of frequencies and dynamics. The vocal stimulus was a
female voice reciting nursery rhymes.
Each fetus was observed and measured for ten minutes while
in the quietest state of sleep, as evidenced by still eyes and body and a
characteristic heart pattern. After this baseline recording, a single earphone,
placed against the mother’s belly, played either music, voice, or sham (tape recorder playing silence) for 15 seconds each. After a 3.5-minute silence, another of the stimuli
was played, and this sequence was repeated nine times, with music, voice, or
sham occurring in random order.
When all the data were collected and analyzed, it turned out
that fetal movements and heart rates during the sham stimuli didn’t differ significantly
from the random fetal events during baseline or silent times. There was a real
reaction, however, during both spoken voice and guitar music: fetal heart rate
accelerated, on average, to a degree that would be very hard to explain by
chance. There were no measurable differences between responses to music and
responses to speech.
One potential problem with this study is that, to avoid
causing maternal anxiety, the mothers did not have earplugs, nor did they
listen to alternate music. We know that fetuses do react to their mothers’
emotions; so, in this case, it is possible that mothers somehow transmitted
information about each stimulus from their nervous system to their fetuses.
Dr. Qahtani points out that some other similar studies have
found decelerations of heart rate rather than accelerations. She posits that
different kinds of musical stimuli may explain contradictory findings. For
scientists, studying music can be mysterious because it is such a complex
stimulus. It can vary, as we know, by pitch, volume, duration, timbre, tempo,
and so many other dimensions. For musicians and music teachers, the same
mystery presents a world of opportunity—to soothe people or to energize them,
or to communicate subtle and deep emotions. Fetuses show incipient responses to
the complexity of music. Fetuses are so attuned to vocal quality and other
characteristics of speech that they can discriminate, in utero, between a stranger’s voice and that of their own
mother. If fetuses are so sensitive to timbre, then how much more so might
newborns be?
“Maturation of fetal responses to music.” Developmental
Science 7:5 (2004), pp. 550-559, Kisilevsky, B.S., Hains, S.M.J., Jacquet,
A.-Y., Granier-Deferre, C., and Lecanuet, J.P.
In the 1980’s a psychologist and amateur musician named
Dr. J.-P. Lecanuet began shifting the focus of his Paris lab from
perception in cats to auditory perception in the human fetus. He became
particularly interested in tempo perception. At the same time, independently, a
researcher named Barbara Kisilevsky in Ontario was also beginning to study
fetal auditory perception after some years studying newborns. In the 1990’s,
when Dr. Kisilevsky spent a sabbatical year at Dr. Lecanuet’s laboratory, the
two strands of research merged.
Early childhood music
specialists often hear mothers assert “I listened to Baby Mozart throughout my
pregnancy,” with a satisfied or defensive tone, as if insisting that they took
their prenatal vitamins and never touched wine. The idea that music magically,
effortlessly benefits development is widespread, but—no matter how much parents
wish it--the support for it is “mostly anecdotal and is perhaps reinforced by a
plethora of commercial audio-recordings (e.g. music, heart sounds) and devices
purported to enrich the fetal environment and increase infant IQ.”
In order to test such claims, Drs. Kisilevksy and Lecanuet
needed to begin by finding out the bare facts of how fetuses respond to music:
do they 'tell us' (by changing their heart rate or moving) that they hear what
we play to them? Do they change their response as they mature? Does music
excite or calm them? Can they detect different tempi? The newly-formed team
chose to study one of the musical genres that infants hear most frequently:
lullabies. A graduate student in Dr. Kisilevsky’s lab was already using Brahms’
Lullaby to soothe babies in the NICU
after painful heelsticks, so it made sense to continue working with that piece.
Dr. Lecanuet prevailed on a professional pianist friend to record a five-minute
track of the Brahms at 69 bpm, the traditional tempo, and another track at 118
bpm, for contrast.
At the time, prior research had
already verified that external music is indeed heard clearly enough to be
recognizable in utero; that the
auditory system is substantially working after 33 weeks gestational age; and
that immediately before birth, babies can detect certain gross auditory
differences such as male/female voice, familiar/unfamiliar voice, and low/high
piano pitch.
While playing the lullaby
recording to the fetuses, the scientists attempted to separate out mothers’
responses from fetal responses by masking the mother’s hearing with earphones
playing dissimilar music (either country or guitar music). They then measured
fetal heart rate and body movements, especially in the thirty seconds before
and after the music started, and again the thirty seconds before and after the
music stopped.
During data analysis, they
separated the fetuses into groups by gestational age (GA). A group of half a
dozen fetuses were between 28 and 32 weeks GA when studied, which means that
their auditory systems were not fully developed. Another half-dozen fetuses
were 33-34 weeks GA, the age at which, previous research has suggested, the
auditory system is fully developed. Over a dozen fetuses were at 35-36 weeks GA
when they participated in this study. Another dozen were called “term fetuses”
because, at 37 or more weeks, they would no longer have been considered
premature had they been born. Indeed, the only fetuses included in the data
analysis were those who subsequently turned out to be healthy term babies.
When the researchers turned the
music on, all age groups showed changes of heart rate. Statistical testing
strongly suggested that these changes could not have occurred by chance. In the
youngest fetuses, heart rates generally accelerated at the onset of music if it
was played loudly: this was thought to indicate arousal. If the same music was
played more softly, heart rates generally decelerated at the onset of music, which
was thought to indicate attention. The deceleration effect became more common
in the older fetuses. The “term” fetuses showed heart rate deceleration no
matter how loud or soft the music was played. In other words, the most mature
fetuses may have been paying some primitive form of attention to the music.
The Canadian team used only the
traditional-tempo recording, but the Paris team played the lullaby twice for
each fetus, in random order: for half the fetuses, they played it first at an
ordinary tempo, 69 beats per minute and then again much faster, at 118 beats
per minute. The other half of the group of fetuses heard the fast version
before the a tempo version. During
the course of the five-minute music, term fetuses showed an increase in heart
rate to the faster tempo, but no change with the normal-tempo music.
Understanding this study depends
on getting comfortable with the technical terms “arousal” and “attention.” The
youngest fetuses may have been exhibiting a startle response in reaction to the
onset of music in their environment. The more mature fetuses, because they may
have been able pay some primitive form of attention to the music, could also
respond differentially to faster and slower tempo. If tempo and timbre are both
salient features of music for fetuses, we are forced to ask how many other
features of music fetuses can also experience with some degree of clarity, such
as melodic contour or rhythmic pattern. We will also want to know whether they
will remember, as newborns, the music they heard while in utero.
“Fetal learning: a prospective randomized controlled
study.” Ultrasound Obstetrics and Gynecology 2002; 20: 431-438. James, D.K.,
Spencer, C.J., and Stepsis, B.W.
David James had long had a research interest in fetal
neurobehavioural development. In the 1990s and there was a lot of discussion
both in the lay press and in the scientific literature about whether fetuses
could learn; Dr. James designed a study to address this question. Some people
studied the spoken word (both maternal and non-maternal), but he decided to
study music because he is an amateur musician and his mother was a professional
musician. In their quest for a music stimulus that was fairly rhythmic and with
a significant bass part, his team started with Carl Orff's Carmina Burana. Parents who recognized the track from the
soundtrack of the 1976 film “The Omen” soon expressed anxiety about the music’s
effects on their fetus, so the researchers switched to another very rhythmic
track with a “wide range of tone: Glenn Miller's Little Brown Jug—dated, but not controversial.”
Twenty pregnant women were studied 92 hours prior to their
elective date of delivery. Each pregnant woman wore headphones on her abdomen
for five consecutive hours. None of the women had been previously exposed to
the Little Brown Jug during pregnancy,
so their fetuses could have formed no associations, whether positive or
negative, with it. For one initial silent hour, researchers took a baseline
recording of heart rate and body movements for all the fetuses. Thereafter, the
experimental group was differentiated from the control group by having a
continuously looping recording of the Glenn Miller track played through the
headphones to the fetus.
Mothers in the control group continued to wear silent headphones
on their bellies. This “sham stimulus” was an attempt to keep the mothers
unaware of whether they were in the experimental group or the control group, to
make this study nearly a “double blind” study.
For the fetuses in the experimental condition, music was
played through the headphones on their mothers’ bellies the entire time. During
the first and fourth hours of this period, fetal heart rate and movements were
recorded for all the fetuses, both control and experimental. Strikingly, during
the fourth hour of hearing music, fetuses who heard music showed significant
differences in their heart-rate and movements compared to fetuses in the
control group. They showed more state transitions (awake to asleep, etc.) and
spent more time awake.
Three to five days after birth, all babies were studied
again in a quiet room, thirty minutes after feeding. The babies’ heart rates
were measured through special neonatal electrodes attached to an
electrocardiogram machine. A trained observer took notes of the infants’ body,
limb, and eye movements. In this neonatal situation, thirty minutes of
“baseline” (no music) were followed by an hour of looped Little Brown Jug music, played through a headphone 2-3 feet from the
baby’s head. All of the newborns, including those in the control group, now
heard this music. All the neonates showed significant differences in their
heart rate and movements while hearing music compared to the silent condition.
They showed more state transitions (awake to asleep, etc.) and spent more time
awake.
There were, however, also marked
differences between those babies who had heard four hours of music in utero and those who had not. The music group changed sleep-wake
state more efficiently and spent more time awake than the non-music group.
The limitations of this study include the fact that mothers
in the experimental group may have become aware of the music vibrating on their
abdomens, and their knowledge or feelings about this may have had an effect on
fetal behavior. Another problem is that fetuses and newborns change
spontaneously and unpredictably: even the control group exhibited significant
changes during their time of listening to silence.
The authors believe their study demonstrates that fetal
exposure to music results in the development of altered behavior in the fetus
before birth and in the newborn period, and consider this to be evidence of a
kind of learning, albeit the most primitive kind. Music and movement
specialists should feel slightly more comfortable than ever before in assuring
parents that their babies’ remarkable abilities include some ability to learn
music.
“An examination of fetal learning before and after
birth.” The Irish Journal of
Psychology 1991; 12: 95-107. Hepper, P.G.
One of the most elegant studies of learning a piece of
music in utero was carried out three
decades ago by British psychologist Peter Hepper. He recruited a group of
mothers who watched one particular television show regularly during pregnancy
and compared them to mothers who did not watch that show. Fetuses whose mothers
did not watch the program exhibited no body movement changes when researchers
played the program’s theme song. Likewise, even in mothers who watched the show
regularly, younger fetuses (29-30 weeks gestational age) displayed no
particular reaction to the theme song of that television show. But fetuses who
were 36-37 weeks along, whose mothers watched the show regularly, changed the
pattern of their body movements when that theme song was played. This suggested
that somewhere between 30 and 36 weeks gestation, fetuses developed the ability
to recognize familiar music. When Dr. Hepper tested these same fetuses as
newborns, again they showed by changing their behavior that they had
formed memory traces of the music. Memory for the theme song disappeared by
three weeks after birth if the mother did not continue to watch the program.
In conclusion, we can tell parents:
Rather than asking whether their baby is old enough to
benefit from music class, perhaps parents should be asking us whether to start
music class when their fetus is at 33 weeks gestational age, or wait until 37
weeks, just prior to the estimated due date. The field of fetal auditory
perception is (forgive the pun) in its infancy, but earliest reports tend
towards supporting Kodaly’s vision that music education should begin “nine
months before the birth of the mother”!
The body of research on all types of prenatal cognitive
abilities is small. The sense of hearing, being the fetus’s most well-developed
distal sense, is naturally the easiest to study and will provide the most
natural opportunity for scientists to determine more about the way that
thinking itself develops in the unborn human.