Brain Rules (Updated and Expanded)

r
value.

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An 
r
value is a quantifiable linear association between two variables. It
measures the tightness of their relationship. 
R
values are assigned a number
between -1 and 1. As an 
r
value gets closer to 1, there is an increasingly
positive relationship between the two variables. My wife, to give one
example, loves chocolate. Every time she eats it, she breaks out into a big
smile. The relationship between chocolate and smile is tight. We could
easily assign it an 
r
value of 1.
In science, we use 
r
values when reviewing multiple investigations done
over a period of years to look for patterns—called a meta-analysis. That’s
usually the kind of study done to analyze whether music is associated with a
boost in academic or cognitive performance. Let’s look at the actual results
in a few areas rumored to be true.
Music training improves math scores.
The best score in the literature
gives the association an 
r
value of 0.16. That’s not much.
Music training improves reading ability.
This sports an 
r
value of about
0.11. In more recent studies, researchers are beginning to detect
improvement in reading skills of musicians compared to nonmusicians, but
more research is needed.
Music training improves IQ.
The answer again is no. Musicians 
are
smarter, but the reason may be that smarter people take music lessons.
Music training improves something useful for academics, right?
Yes:
spatiotemporal reasoning. That’s the kind of reasoning that allows you to,
among other things, rotate three-dimensional images in your head. This is
the kind of skill used by an architect or engineer. There’s an 
r
value of 0.32
between the two if you take group instruction in piano, 0.48 if you take
individual lessons.
This is not an impressive track record, taken together.
Nonetheless, 
r
values even lower than these can make headlines. One of
my favorite examples is the so-called Mozart Effect. Listening to Mozart,
the news stories claimed, will improve your ability to do math. An entire
cottage industry grew up around this phenomenon, selling DVDs and CDs
marinated in Mozart, then marketed to anxious parents worried about their
child’s cognitive development. At one point, the governor of Georgia issued
classical music CDs to the parents of every newborn in the state. The basis
of all this enthusiasm was a tiny little paper that got a giant dollop of
publicity because it was published in the prestigious journal 
Nature
. The

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paper showed that when undergraduate students listened to 10 minutes of
Mozart just before taking spatial tests, their scores improved. The boost was
not strong, and the statistical analysis was even less so. The 
r
value was a
miserable 0.06. 
Nature
issued a critique of the paper a month later,
questioning the finding. Scientists who tried to replicate the results found
that 
any
pleasurable listening (or reading) experience had the same effect—
one lasting about 15 minutes. But that not-so-shiny fact generated almost no
publicity. The lead author of the original study has denounced the cottage
industry, and years later reflected that the money Georgia’s governor
appropriated for the music CDs might have been better spent on music
education in the public schools.
That study was published more than 20 years ago. But even when I
lecture on brain science today, I encounter people who think classical music
is good for your brain. Happily, music does do the brain some good. First
we’ll look at the effects of taking music lessons, and then the effects of
listening to music.