Dual N-Back and the Science of Brain Exercises

The “train your brain” software market is hot right now. Seemingly overnight, dozens of games (from BrainAge to Lumosity) have sprung up. They make bold claims, like being able to reverse the cognitive “aging” of the brain.

I’ve discussed many such products in my educational software reviews; this post will focus on the science of  improving or maintaining your brain function.

What Is Brainpower, Anyways?


When companies talk about brain exercises, they usually make vague claims about “improving your memory” or “increasing your brainpower.” Unfortunately most qualities of a so-called good brain are hard to measure. What is the test for “brainpower?” Do we measure it via IQ? What does this word even mean?

Most people regard IQ (“intelligence quotient”) as a catch-all quantification of intelligence, yet many researchers now think that IQ (as well as other forms of standardized brain testing) are not nearly so important as we once thought. IQ was dreamed up in the early 1900s as a way to identify promising young students, yet as Charles Duhigg explains in The Power of Habit:

Self-discipline has a bigger effect on academic performance than does intellectual talent.

In the Social Animal, David Brooks explains the diminishing returns of IQ:

Once a person crosses the IQ threshold of 120, there is little relationship between more intelligence and better performance. A person with a 150 IQ is in theory much smarter than a person with a 120 IQ, but those additional 30 points produce little measurable benefit when it comes to lifetime success.

IQ was an attempt to measure the ability to solve a problem. Other attempts have been made, and while the educational system may have created better tracking systems over the years, science has yet to be able to find a strong correlation between such numbers and real-world performance. This is a classic example of a failure to transfer effectively. What such tests seem to measure, more than anything else, is simply how well someone can perform on a test.

What About Memory?

Everybody has suffered the frustrating experience of losing car keys or forgetting a name. Maybe you’ve even had the unnerving experience of walking downstairs and forgetting why you did so, or forgetting what you were saying in the middle of a sentence.

The idea of improving memory is an alluring one since it is a concrete skill which we use in every day life. Even better, memory is much easier to quantify than some vague notion of “intelligence.” I’ve even written extensively about memorization techniques that actually do work and some of the research into fancy memorization software, like SRS.

First, it’s important to understand that there are many types of memory. There’s short-term (“working”) memory, and long-term memory. There’s also declarative (fact-based) and non-declarative (muscle-memory). All forms of memory are subject to the forgetting curve, as well. Most people are interested in increasing declarative memory. A better long-term declarative memory might mean remembering names and facts better over time. Working memory, on the other hand, can aid with performing complex tasks like mathematics.

Again, the problem with memory training tends to be with transfer. Even if you played a hypothetical game which taught you to memorize faces and names, it might not actually help you much at a party. In Moonwalking with Einstein, the U.S. memorization champion laments that he can win every national name-recollection contest yet still loses his keys and forgets names at parties.

It’s hard to train memorization or working memory as a generic skill, but some researchers have tried.

Dual N-Back Training

Some of you may remember the old game, Simon:


In Simon, the objective was to be able to remember a sequence of flashing lights and sounds. At first the pattern would be simple: just one or two button presses. Over time, the pattern would become increasingly complex until you inevitably were unable to remember it.

This children’s game bears some striking similarities to the research on Dual N-Back training, which was first created by Wayne Kirchner in 1958. The “N” in n-back refers to the number of things you need to remember, and the “dual” part refers to using multiple senses (light and sound!) In the words of Wikipedia:

The n-back task captures the active part of working memory. When n equals 2 or more, it is not enough to simply keep a representation of recently presented items in mind; the working memory buffer also needs to be updated continuously to keep track of what the current stimulus must be compared to. To accomplish this task, the subject needs to both maintain and manipulate information in working memory.

 The N-Back test has become one of the standard measures of fluid intelligence, which is the ability to think logically and solve problems. What’s significant about fluid intelligence is that it’s independent of knowledge. It attempts to measure the ability to respond to novel, challenging situations. It is, perhaps, the closest we have to a measure of brainpower.

After a 2008 paper suggested that the Dual N-Back test could improve fluid intelligence by repeated practice, a handful of such apps popped up. You can download a Dual N-Back game on for iOS, for example. Unfortunately, the research paper which spurred this mini-craze is largely contested. Other researchers have failed to replicate the studies. Students get better at the Dual N-Back test, but yet again, the results do not actually transfer in to generalized fluid intelligence.

What Really Works?

The Dual N-Back test is just one among many crazes. Each time a promising bit of research comes out, there are people trying to put that research to use.

I’ve yet to hear of any piece of software or any “trick” that truly transfers well. That doesn’t mean that tools like software aren’t useful, though. It just means that learning tools should be specialized to the skill they’re trying to improve. Instead of trying to create a “magic brainpower” solution, companies should seek to improve a specific skill.

There are ways to exploit the brain’s natural abilities to learn more, faster though. That’s what this blog is all about: the science of what actually works for improving learning. If you subscribe to the email list, you’ll receive an ebook and collection of the best research on how to improve your learning.

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