When Homework is a Waste of Time
Most after-school assignments are based on
out-of-date and often ineffective methods
We often hear
passionate arguments about how American students have too much homework, or too
little. But I believe that we ought to be asking a different question
altogether. What should matter to parents and educators
is this: How effectively do children’s after-school assignments advance
learning?
The evidence
suggests that as of now, homework isn’t making the grade. Although surveys show
that the amount of time our children spend on homework has risen over the past
three decades, American students are mired in the middle of international
academic rankings: 17th in reading, 23rd in science, and 31st in math,
according to the latest results from the
Program for International Student Assessment (PISA). In a 2008 survey, one-third of
parents polled rated the quality of their children’s homework assignments as
fair or poor, and four in ten said they believed that some or a great deal of
homework is busywork. A recent study, published in the Economics of Education
Review, reports that homework in science, English and history has “little to no
impact” on students’ test scores. (The authors did note a positive effect for
math homework.)
Fortunately,
research is available to help parents, teachers and school administrators make
homework smarter, although these particular innovations have yet to be applied
outside the classroom. A new discipline, known as
Mind, Brain and Education, has recently emerged that is
devoted to understanding and improving how people absorb, retain and apply
knowledge. A collaboration between psychologists at Washington University
in St. Louis and teachers at nearby Columbia Middle School, for example, lifted seventh- and
eighth-grade students’ science and social studies test scores by 13 to 25
percent. The field’s methods may seem unfamiliar and even counterintuitive, but
they are simple to understand and easy to carry out. After-school assignments
are ripe for the kind of improvements this new science can offer.
“Spaced
repetition” is one example of the kind of evidence-based technique that
researchers have found has a positive impact on students’ learning. Here’s how
it works: instead of concentrating the study of information in large one-shot
doses, as many homework assignments currently do—reading about, say, the Civil
War one evening, and Reconstruction the next—learners encounter the same
material in briefer sessions spread out over a longer period of time. With this
approach, students would be re-exposed to information about the Civil War and
Reconstruction in their homework a number of times during the semester. It
sounds unassuming, but spaced repetition produces impressive results.
Eighth-grade history students who tried a spaced approach to learning had
nearly double the retention rate of students who studied the same material in a
consolidated unit, reported researchers from the University of California-San
Diego in 2007. The reason the method works so well goes back to the brain: when
we first acquire memories, they are volatile, subject to change or to
disappear. Exposing ourselves to information repeatedly over time fixes it more
permanently in our minds, by strengthening the representation of the
information that is embedded in our neural networks.
A second
learning technique, known as “retrieval practice,” employs a familiar tool—the
test—in a new way: not to assess what students know, but to reinforce it. We
often conceive of memory as something like a storage tank, and a test as a kind
of dipstick that measures how much information we’ve put in there. But that’s
not actually how the brain works. Every time we pull up a memory, we make it
stronger and more lasting—so that testing doesn’t just measure, it changes.
Simply reading over material to be learned, or even taking notes and making
outlines, as many homework assignments require, doesn’t have this
effect. In one experiment, language learners who employed the retrieval
practice strategy to study vocabulary words remembered 80 percent of the words
they studied, while learners who used conventional study methods remembered only about a third of them. Study
subjects who used retrieval practice to learn from a science textbook retained
about 50 percent more of the material than those who studied in traditional
ways, reported researchers from
Purdue University in 2011. Students—and parents—may groan at the prospect of
more tests, but the self-quizzing involved in retrieval practice need not
provoke any anxiety. It’s simply an effective way to focus less on the input of
knowledge (passively reading over textbooks and notes) and more on its output
(calling up that same information from one’s own brain).
Another common
misconception about how we learn can render homework much less effective than
it might be. Most of us assume that if information feels easy to absorb, we’ve
learned it well. In fact, just the opposite is true. When we work hard to
understand information, we recall it better; the extra effort expended signals
the brain that this knowledge is worth keeping. This phenomenon, known as cognitive disfluency, promotes
learning so effectively that psychologists have devised all manner of “desirable
difficulties” to introduce into the learning process: for example, sprinkling a
passage with punctuation mistakes, deliberately leaving out letters, shrinking
font size until it’s tiny, or wiggling a document while it’s being copied so
that the words come out blurry. Teachers are unlikely to start sending students
home with smudged or error-filled worksheets, but there’s another kind of
desirable difficulty—called interleaving—that can
readily be applied to homework. An interleaved assignment mixes up
different kinds of situations or problems to be practiced, instead of grouping
them by type. When students can’t tell in advance what kind of knowledge or
problem-solving strategy will be required to answer a question, their brains
have to work harder to come up with the solution—and the result is that they
learn the material more thoroughly.
A study
published in 2010 in the journal Applied Cognitive Psychology asked
fourth-graders to work on solving four types of math problems, and then to take
a test evaluating how well they had learned. The scores of those whose practice
problems were mixed up were more than double
the scores of those students who had practiced one kind of problem at a time.
The effectiveness of interleaving has been demonstrated many times in the
laboratory, yet real-world homework assignments still commonly present problems
of a single type together.
Homework has long
been an academic laggard, slow to adopt scientifically-supported approaches to
learning. No wonder it’s assailed by critics on all sides, whether they believe
homework is piled on too heavily or given too sparingly. Maybe the heated
debates about the amount of homework children are assigned would cool if it
became clear that the homework was effectively advancing their learning. At our
resource-strapped public schools, the application of such research-based
strategies to homework is an untapped opportunity. Science has shown us how to
turn homework into a potent catalyst for learning. Our assignment now is to
make it happen.
