As I blogged earlier, my arithmetic performance suddenly improved about a month ago (close-up above). How fast the change: On February 2 at 8 am I took the test; my scores were roughly the same as they had been the past month. At 2 pm the same day, I took the test again and was about 50 msec faster. (In reaction-time experiments, a surprising 50-msec effect is huge.) I remained faster for at least several weeks. Comparing the last 30 sessions before the shift to the first 30 sessions after the shift, t (38) = 11, p = extremely small. In an experiment, comparing treatment and baseline, t> 3 is very good and t > 4 is extremely good.
What might have caused this?
I moved to Beijing in October. Eventually I ran out of the Spectrum Organic flaxseed oil I’d brought with me and started drinking a Beijing brand called Joyful Organic. When I returned to Berkeley I brought a few bottles of it with me and continued to drink it. In late January I ran out; the evening of January 29 I started drinking Spectrum Organic again. Four days later my arithmetic scores sharply improved.
It’s really plausible that the improvement was due to the change in flaxseed oils. Flaxseed oil had made a difference (versus nothing) with a very similar task. A few weeks before the shift, a friend had asked how I knew if my Chinese flaxseed oil was good; I’d said I’d find out when I switched back to Spectrum Organic.
But why was the improvement delayed four days? I started studying flaxseed oil because one evening I took several capsules and the next morning noticed my balance was better. And if the improvement is going to take that long, why would it happen so sharply after the delay? I can’t even begin to answer these questions.