This paragraph from the original paper explains beautifully how little benefit brain-training really provides: "To illustrate the size of the transfer effects

This paragraph from the original paper explains beautifully how little benefit brain-training really provides: "To illustrate the size of the transfer effects observed in this study, consider the following representative example from the data. The increase in the number of digits that could be remembered following training on tests designed, at least in part, to improve memory (for example, in experimental group 2) was three-hundredths of a digit. Assuming a linear relationship between time spent training and improvement, it would take almost four years of training to remember one extra digit. Moreover, the control group improved by two-tenths of a digit, with no formal memory training at all." This is far from the first study of its kind. People have been trying for decades to find any sort of training task that can improve general cognitive ability, and there is simply no evidence that one exists. Tests with sufficiently high g-loading are virtually impervious to any form of preparation or training. The closest anyone has ever come to finding one that works is the discovery that the dual n-back task improves scores on Raven's Progressive Matrices (which is very much the gold standard of g-loaded tests), and that's highly suspect given that both n-back and RPM involve the very idiosyncratic task of holding three-by-three matrices in working memory. As important as discovering a general IQ-raising task would be to psychology, there's nothing especially depressing about one not existing. Remember: You can still learn things. All this research tells you is that if you want to get good at some particular task, you have to train either at that task specifically, or something that's in some way related to it. Playing Tetris, memorizing chess openings, or practicing Bach's Goldberg Variations is simply not going to help you become a better programmer. For that, you need to program.