Because we have a lot off history of researching this topic, wherein the benefits of mental practice usually appears to be very specific and not general.
I am curious if this is as much a reflection on not knowing how to practice, versus only playing at it. If I weight lift but never progress above a 1kg weight, I would not be shocked that I don't get any of the advanced muscle benefits of weight lifting. Same for pretty much any physical exercise. If I don't push past my current limits, I am not surprised at lack of growth.
To that end, playing sudoku, but only staying at the "1 star" difficulty puzzles, I don't know why I would expect brain growth, as it were. Learning the strategies and modeling that is needed to solve the advanced ones, though, is a very different thing.
1. People imagine without any evidence, but only a plausible story, that X is good for Y (say for instance, vitamin C for colds, because vitamin C is involved in the immune system)
2. Study after study is done finding no benefit, but each study you quote, someone finds some nit pick about it "well maybe the dosage wasn't high enough" or "maybe they did/didn't take it with calcium" and then continue to believe there must be some way to derive benefit
I mean, this isn't wrong. At the same time, it took a long time for studies to show that ulcers are not just reactions to stress. Study after study for many years showed the opposite. This isn't even getting into the problems of studies with nutrition, in general.
That said, I should be clear that I'm not pushing for learning some of these "brain games" for their own sake. I am more throwing out that equivalent of the Tyler Durden quote regarding chickens. :D
