In January 1998, the governor of Georgia asked his state's legislature for 105,000 dollars. Zell Miller wanted every baby born in the state to go home with a tape or a CD of classical music. Many legislators balked. In the end they didn't have to pay. Sony offered the recordings free. It had a big factory in the state. Hospitals were to hand them to new parents along with the diapers. The album was called Build Your Baby's Brain Through the Power of Music. That May, Florida passed a law telling day-care centers paid by the state to play classical music every day.
Miller's evidence was an article in Time magazine. It cited a study said to show that listening to Mozart briefly lifted college students' IQ scores. He hadn't consulted the researchers. He also said this: "No one questions that listening to music at a very early age affects the spatial, temporal reasoning that underlies math and engineering and even chess."
Quite a few people were about to question it. Does music make you smarter? The last lecture showed years of practice redrawing the brain's maps for the hands and the ears. This one asks whether music reaches anything further. By smarter I mean reasoning, vocabulary and marks at school, and above all IQ, the score on a standard intelligence test.
The evidence comes from four comparisons, each fairer than the one before. Mozart against silence, and then against a story. Lessons, measured on the skills they train and on skills far from music. Children who chose lessons against children given them by lottery, and against their own twins. And last, two big reviews of all the trials against each other, with the gains close to music that hold up. One question runs through all four. Compared with what?
The Mozart study came out in the journal Nature in 1993. Its first author was the psychologist Frances Rauscher. College students listened for ten minutes to a Mozart sonata for two pianos, and then took a test of spatial reasoning. They did better than they had after sitting in silence, or after relaxation instructions on tape. The gain came to the equivalent of eight or nine IQ points. It lasted ten to fifteen minutes. The finding became known as the Mozart effect.
Look at what was measured: one kind of skill, in grown students, for about a quarter of an hour. Critics later attacked the idea that Mozart makes people smarter, and Rauscher's answer was short. "We made no such claim," she wrote. In her account, the effect was limited to spatial tasks that involve picturing shapes and putting steps in order.
The claim grew as it was retold, and two researchers at Stanford measured how. They found 478 articles about the Mozart effect in America's fifty biggest newspapers, from 1993 to 2002.
In 1994, eight articles in ten mentioned college students. After 2000, about three in ten did.
Babies went the other way. No article mentioned them in 1995, and more than half did by 1999. In the researchers' words, there was "no scientific research whatsoever" linking music and intelligence in infants.
Then came the checks. In 1999 a psychologist at Harvard pooled sixteen studies. Against silence, the average gain came to 1.4 IQ points, a small fraction of the original eight or nine. In the same issue of Nature, three labs that had tried to repeat the finding reported no effect at all. "A requiem may therefore be in order," they wrote. Rauscher replied that other labs had found the effect. She compared it to baking: some people can't get bread to rise, and that doesn't disprove yeast.
The last lecture introduced Glenn Schellenberg, who studies what music lessons do for children. In 1999 he and Kristin Nantais tested where the lift came from. Their students sat in a soundproofed booth with headphones on. Each listened for ten minutes, then did a paper-folding test on a computer. A drawing showed a sheet of paper folded and cut. The student picked which of five pictures showed it opened out.
In the first experiment, each student had ten minutes of music one day and ten minutes of silence on another. They did better after the music, and Schubert worked as well as Mozart. Compared with what, though? Ten minutes of silence is dull. So in the second experiment, the silence was swapped for a story. Each student heard the Mozart one day. On another day they heard a Stephen King short story, read aloud, for the same length of time. After which did they score higher? On average, neither. Then the team asked each student which they had preferred, and about half chose each. Those who preferred Mozart scored higher after Mozart. Those who preferred the story did a little better after the story.
The two concluded that the Mozart effect "has nothing to do with Mozart in particular." They noted that every lab that had found it had compared Mozart with silence, a relaxation tape or repetitive music. In Schellenberg's account, Mozart beats those because it leaves people in a better mood and more alert. That helps on a hard spatial puzzle. Set against something people enjoyed as much, the music added nothing.
Lessons are a different kind of claim. They mean months of practice. Could that reach beyond music? Psychologists call it transfer when you get better at one thing because you practiced another. Near transfer goes to something closely related. The Boston team from the last lecture, who followed children through keyboard lessons, gives an example, fingers trained on an instrument getting quicker at typing. Far transfer goes to something with little in common. The team's example is reading rhythms in music helping a child with fractions. The claim that music makes you smarter is a claim of far transfer.
Far transfer is the hard one. Lab studies going back to 1901 find it much rarer than near transfer. A skill carries over most when two tasks share a great deal. In one large review, memory training improved other memory tests for a while, and did nothing measurable for reasoning. In a study Fernand Gobet co-wrote, chess masters were asked to remember positions, or find the best move, from openings they don't usually play. They did drastically worse. So even at chess, skill carries over only in part. Asking piano lessons to carry over to vocabulary is asking a great deal more.
The Boston children were six-year-olds, scanned before and after fifteen months in which about half had keyboard lessons. They took tests of both kinds. The near ones were a finger test on number keys, and telling short tunes apart. The far ones included vocabulary, reasoning puzzles and building patterns from blocks. By the end, the lesson children had improved more than the others on the near tests. On the far ones, they improved no more. The gains landed on the skills the lessons trained.
Mozart, then, lifts the mood for a few minutes, and lessons sharpen what they train. Neither explains a stubborn fact. In study after study, people who have had music lessons score higher on intelligence tests than people who haven't. Comparisons of musicians with non-musicians find a gap four or five times the size of the typical gain in trials of lessons. Why do the people who took lessons score higher?
The answer begins with who takes lessons. The last lecture gave Schellenberg's view: children who take lessons already differ from other children, in ability, family background and personality. They tend to be more curious, for one, and more drawn to the arts. Lessons cost money, and they need parents who back them. In one study, about a quarter of eleven-year-olds whose families were above the poverty line took private music lessons. Among children living in poverty, one in twenty-five did. Schellenberg puts it bluntly: musicians are "as much born as they are made."
The children who start lessons are often ahead before the first one. The last lecture's Boston children scored higher on all seven tests before any lessons, though no single gap was large. A team at the University of Granada, in Spain, looked across fourteen studies in which children or their families had chosen music. Most of those studies were too small to see a gap, so they reported their groups as evenly matched. Pooled, the gap showed. The children who had chosen music had a head start.
There are two ways round a head start. One is a lottery, in which chance decides which children get music lessons. The other is to compare twins. A lottery works best with one more feature. The children who don't win lessons should get something else, a comparison class. It should be new and engaging, and taught the same way, but without music. Then the music is the only difference.
Schellenberg ran an early lottery trial of music lessons himself, in Toronto. A local newspaper advertised free weekly arts lessons for six-year-olds. Families had to agree to take part whichever group their child landed in. Then 144 children were drawn by lottery into four groups. One group learned keyboard. One learned singing by the Kodály method, which teaches with songs, hand signs and clapping. One took drama, which has rehearsing, memorizing scripts and expressing emotion, but no music. And one waited a year for keyboard lessons. The lessons ran for thirty-six weeks at the Royal Conservatory of Music, in classes of six. Most of the children took a full IQ test before the lessons, and again after the year was over. The testers didn't know which group a child was in.
What happened to the children with no lessons? Their IQ went up too, by about four points. Every group's did. That year the children started first grade, and going to school raises IQ. The question is which groups rose most. The two music groups gained seven points on average, and the other two groups 4.3. Schellenberg titled the paper "Music Lessons Enhance IQ." The drama children gained something else. By their parents' ratings, their social skills improved, while the music children's didn't change.
Compared with what, though? Against the children who waited, the music lead was clear. Against drama alone, keyboard was about one point ahead, and singing about two and a half. Some ways of analyzing the data called that gap real, and others didn't. The music children had also barely practiced between lessons, about ten to fifteen minutes a week.
In 2013, a much larger trial in English primary schools tried to repeat the result. It split 909 children of about the same age by lottery, within their classes. A third learned violin or cello, a third learned singing, and a third took drama, once a week for 32 weeks. By the end of the year, the music groups had gained no more than the drama group, in math or in literacy. The difference was close to zero, even for children from poor families. The violins and cellos were meant to go home for practice. In most schools, they didn't.
Looking back on his own trial, Schellenberg called its results "weak, without successful replication for almost 15 years."
One objection is fair. Maybe a year is too short, and six-year-olds don't practice enough. The Granada team argues just that. Twins speak to it, because the comparison isn't a year of lessons. It's a twin who practiced a great deal against one who didn't. Researchers in Sweden studied more than 10,500 twins. Across all of them, those who had practiced more music had somewhat higher IQs. Then the team compared each twin with the other. They explain that this controls for genes and for the home the twins shared. Compared with what? This time, with their own twin. Was the practiced twin's IQ higher? It wasn't. The team's reading is that the same genes nudge people toward both, toward practicing and toward a higher IQ. They write that their findings strongly suggest the link between practice and IQ isn't one of cause and effect. In my view, that doesn't rule out a small effect from years of lessons. But it suggests that much of the famous gap comes from what children bring to the first lesson.
What do lessons add on their own? Two big reviews have pooled the trials, and they disagree. The first is by Giovanni Sala and Fernand Gobet, of the chess study. Across 54 studies, the music children gained a little more than the others. But the gain sat in the weaker studies, those with neither a lottery nor a comparison class. Where there was either one, the gain was about zero. They point to the two largest trials in the field, England's among them, and both found nothing. Their conclusion was blunt: "since there is no phenomenon, there is nothing to explain."
The Granada team answered with a review titled "Please don't stop the music." Its point was that "music lessons" had meant very different things. Most of Sala and Gobet's lottery studies weren't lessons on an instrument. They were group music classes, or computer programs that train musical skills. The Granada team argues that an instrument asks more of a child: two hands working together, and nimble fingers. It also leans on memory and attention. So they pooled only trials of instrument lessons, and found a small gain. It held up in the lottery studies. They also set their instrument trials beside the other music classes from Sala and Gobet's review. In lottery studies, the instruments kept a small gain, and the other classes showed no reliable gain.
How big is the gain? The team puts it at about three IQ points. Pick one child at random from the lesson groups, and one from the comparison groups. By their count, the child with lessons comes out ahead 57 times in a hundred, where chance alone would give 50. Every such figure is an estimate, with a range it could really fall in. In the few lottery studies that had a comparison class, the best guess was still a small gain, but its range reached down to zero. The Granada team writes that three points "probably makes very little difference in daily life." They add that longer programs might do more, and that poorer children seem to gain more, though England's trial saw no such thing.
Strip away the sharp words, and the two sides agree on more than they dispute. Both accept that children who choose music start ahead. Both put what lessons add, in a fair trial, somewhere between nothing and about three IQ points. The fight is over whether it's nothing. My own judgment is that the Granada team is right to keep instruments apart, though that's contested. But on their own numbers, the gain is small, and it rests on few trials.
That is about as far as the evidence on IQ goes. A near claim is a different matter. It asks music to travel only a short way, to a skill that uses the same machinery. The second lecture raised a related hope, that music lessons might help children learn to read. Shared machinery offers a route: music training might sharpen how the brain encodes speech, and that might help reading.
Aniruddh Patel built a theory of how that could work. The second lecture met him arguing that music and language share some of their processing resources. He calls the theory OPERA, from the first letters of five conditions. The first is overlap. Music and speech must share brain machinery for some feature of sound, such as the pitch of a voice or a note. The second is precision. A note one small step out of place can be a wrong note. Speech is more forgiving. Mandarin speakers in a quiet room understood sentences even with the rise and fall of pitch flattened out. So music asks more of the shared machinery than speech does. The other three conditions are about the practice. It has to be enjoyed, repeated often, and listened to closely. Patel argues that when all five are met, the shared machinery sharpens beyond what speech needs, and speech gains too.
One study set out to catch a near gain as it happened. A team at Northwestern University worked with Harmony Project, a free music program for children in Los Angeles neighborhoods marked as gang-reduction zones. Forty-four children from its waiting list were split into two groups, mostly by lottery. Some began lessons at once, and the rest a year later. Once a year, each child heard two syllables, bah and gah, six thousand times each. Electrodes on the scalp recorded the brain's response. The question was how sharply it told the two syllables apart. One year of lessons left it no sharper. Two years sharpened it, and children who had spent more hours on their instruments had gained more. The team credits two of Patel's conditions: lessons that trained the children's attention on sounds, repeated over two years. It notes that the gains were small, and that it had no comparison class. Any engaging program might have done as much.
Schellenberg's review grants one gain near to music. In his reading, the most reliable results come from training built around rhythm. In one trial, children aged eight to eleven with dyslexia had seven months of either rhythm-focused music lessons or painting lessons. The music group improved more at hearing the separate sounds inside words, and at reading aloud. Even so, a computer program built for those sounds has also worked, so the music itself may not be needed. And the Boston children's keyboard lessons, for one, didn't improve their test of those sounds.
Does music make you smarter? Listening doesn't, beyond a pleasant few minutes. Lessons are another matter. They reliably make children better at music, with quicker fingers and a sharper ear. The famous IQ gap between children who take lessons and children who don't is largely about who takes them. Compared with what? That question did most of the work. Each time the comparison got fairer, the gain got smaller. A story replaced the silence, and Mozart's lift was gone. Drama replaced a year of waiting, and the music lead shrank to between one and two and a half points. A twin replaced a stranger, and the link between practice and IQ disappeared. Only the review of instrument lessons kept a gain through the fairer trials, about three IQ points. Even those authors say three points probably makes little difference in daily life.
Closer to the sound itself, the evidence is kinder, if thinner. Rhythm training seems to help children hear the sounds inside words. In one small study, two years of lessons sharpened how children's brains told bah from gah. Notice where lessons did best: close to the sound, on skills that use the same machinery as music. The next lecture asks what that narrower reach can do for a brain hurt by Parkinson's disease or a stroke.
Schellenberg practiced the piano every morning before school, from the age of five until he was sixteen. He has no doubt it shaped his development, and even his brain. What he doubts is that the same years would do the same for another child. In one sentence, Schellenberg sums up the research: "Music training improves musical skills, which should be enough."