Science in Action: Omega-3 (letter-counting test)

At a reading, the novelist Dennis McFarland said that the hardest part of writing The Music Room had been after breaks in writing it. Before he could resume, he had to reread what he’d written so far. This became so painful that he forced himself to never stop.

Because of a break due to wrist problems, I’m going to backtrack a little. When my wrist started to hurt, I had been learning a new way to measure brain function. It’s a reaction-time task that I can do almost anywhere. On each trial I see four letters. For example:
4 letters
The task is to respond as fast as possible how many of the letters are from the set {A, B, C, D}. In this case the answer is 4, so I would type “4”.

Here is another possible display:
4 more letters
The correct answer is 3. The possible answers are 1, 2, 3, and 4; I just leave my fingers resting on those four keyboard keys.

As soon as I respond to one display, the next appears. Each test has 4 blocks of 50 displays (= 200 trials) and takes about 4 minutes.

I slowly got better — faster and more accurate. This graph shows how my reaction times decreased:
how speed improved (reaction times decreased)
When I started the task, I had to hit Enter after typing the answer (e.g., type “3” then hit “Enter”). After 50 tests, I learned about an R function that got rid of the need to hit Enter after typing the answer. I could just type the answer (e.g., just type “3”).

This shows how my accuracy improved:
how accuracy improved

The points become more widely spaced around July 24 because at that point I started learning another reaction-time task. After I hurt my wrist I decided I was trying to do too much.

3 Replies to “Science in Action: Omega-3 (letter-counting test)”

  1. Does that accuracy graph indicate that your accuracy improved after the change to just pressing the number keys? Could the improvement have been caused by that change? That would be kind of weird.

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