[InkCanon]

My own experience with Dual N-Back 1) I did it for a month. Probably some improvement, although I did not have any specific test done. Probably the most tangible use is really feeling how working memory (and losing it) is like and having better control. In the same way you might suddenly realize how breathing is and controlling it after learning meditation.

2) The study specified dual N back imposes a pretty demanding regiment. It's 12 sessions daily, consecutively for ~month. It takes about 20 minutes each day of intense focus.

3) There's naturally going to be a lot of survivorship bias in reviews. But you could argue it doesn't make your intelligence worse, so there's only net upside.