Friday, March 9, 2012

The N-back Experiment: Analysis

N-back is cognitive exercise developed by Wayne Kirchner in 1958 in order to test working memory. In 2008, PNAS published a research paper by Jaeggi, Buschkuehl, Jonides, and Perrig that concluded that prolonged use of n-back improved fluid intelligence. Shortly thereafter, the scientific journal Intelligence published a research paper by Moody that called into question the methodology used in the former study. So, does practicing n-back make you smarter? Let's find out.

In order to see if n-backing makes me any smarter, I'll need a reliable way to figure out how smart I am both before using n-back and after. The obvious solution is the IQ test. IQ is far from being a perfect measure of intelligence, but it is the most widely used test by psychometricians (suggesting that there aren't any better alternatives). Lucky for me there are several that are available for free on the Internet.

Unfortunately, like most tests, IQ is subject to the practice effect. What this means is that even if the intelligence of the test-taker doesn't increase, they may score higher on a later test for the simple reason that they have practice taking that particular test under the same conditions. To avoid this I could either take the test over and over again until the practice effect stops increasing my score or space the testing out far enough so I lose familiarity with it. For this experiment I will utilize the later strategy and only take a particular test 2 times (total) during the entire experiment. Because the practice effect cannot be completely eliminated, I will only consider an increase of equal to or greater than 5 IQ points to be an increase in my intelligence (rather than simply my performance on a given test). It should be noted that this value is simply an educated (barely) guess and is not the result of some kind of learning curve calculation.

For the purposes of this experiment, I chose a test based on the Raven's Progressive Matrices used by the Mensa International chapter in Denmark. The exact test can be found here.

  • Pre-Experiment IQ: 118

Starting 04/01/2013, I will start a n-back regimen of 20 minutes per day (in one continuous session), everyday. I will continue for 60 days and then retest my IQ and post the results. The precise platform I will be utilizing is the (free) Brain N-Back application for the Android operating system running on my Samsung Galaxy S smart phone.

I don't have very high hopes that the results will measure up. After all, people have been trying to increase their IQ for decades (at least) with little success and the original study has yet to be replicated by other researchers. I estimated the probability it will work here. I'll post an appraisal of the objective data I collect as well as my subjective impression a short time after completing the experiment.

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