From the article:
We wish that 25 years ago the Albert Einstein College of Medicine thought of doing side-by-side comparisons of different kinds of dancing, to find out which was better. But we can figure it out by looking at who they studied: senior citizens 75 and older, beginning in 1980. Those who danced in that particular population were former Roaring Twenties dancers (back in 1980) and then former Swing Era dancers (today), so the kind of dancing most of them continued to do in retirement was what they began when they were young: freestyle social dancing -- basic foxtrot, swing, waltz and maybe some Latin.
While he's inferring a lot here, I'd suspect this is accurate, and the most prevalent dancing in that age group was partnered lead-follow dances - which is what Powers means by "social dance". The guy is an historian and teacher of social dance.
I doubt that the limit of the benefits, even from dementia in particular, are from making lots of quick decisions. An xbox would be enough for that.
Pleasant physical contact for hours on end with members of the opposite sex, with expressive interaction with your partner and the music, in a community of people similarly engaged. I'd expect that to be good for your mental health in an enormous number of ways. And that's not even counting the cardiovascular benefits of hours at a time of mild aerobic exercise, or the exercise to your nervous system in terms of balance and proprioception.
I've been social dancing for about 15 years. Mainly Salsa for the last decade. I'm pretty good. I'm in my mid 40s, and pretty young things in their 20s will just light up and give me a big hug when they see me because I can twirl them around and show them a good time on the dance floor. I suspect that's good for my mental health. The health benefits of social dance are likely enormous, particularly for overly intellectualized introverted technoweenies completely out of touch with their own bodies, like I once was. I share that on the off chance that there is someone on this list that bears a passing resemblance to that description, and could similarly benefit from a new hobby.
Frequent dancing causes a 76% reduction in the risk of dementia. The benefit seems to be from freestyle social dancing, though I don't think that part is as well-verified. The benefit seems to be from making large numbers of quick decisions.
I wonder if playing jazz has similar good effects.
For something a little geekier, Shiva Nata, a system of keeping the mind fresh by doing more and more complex movements. The author of the blog is a silly person, but the system seems to be for real.
Edited to correct html which was entered in the text field instead of the html field. It wouldn't surprise me if having to deal with electronics and computers tends to prevent dementia, considering the number of fiddly and changing details one has to deal with. Or is fun required?