I eventually got round to checking out some of these links. Interesting but nothing very relevant. Some links were dead in the sense that I got no response when I posted a question; some were narrowly focussed on maths and programming. And some were on the theme of communicating knowledge more effectively, whereas my concern is with simplifying the knowledge itself.

Thanks. I will have a look.

I'm sure you have a good point!

Thanks, I will check your suggestions, none of which I know about. (I am new to effective altruism.) I did do a general google search a few years ago which did not turn up much.

Thanks for your comment. I intend the idea as a principle to be taken into account when designing cognitive frameworks, not as a specific project. Many (not all) ideas are unnecessarily complicated so there are lots of advantages of simplifying them, or tackling problems via an alternative route. But to the best of my knowledge this is not something that anyone has looked at systematically. I don't know much about stack overflow but will look into it.

Fair comment. The 50% business was just a hypothetical thought experiment to illustrate a possibility, not a figure with any evidence behind it! But I do think that the problem of knowledge getting more and more complicated is a serious problem and will become more so in the future. If people can't see what's going on, fake news will thrive.

Very interesting in lots of ways. Hippo sounds a bit like Brave New World to me, which isn't entirely to knock it, but I wouldn't like an app to be in charge of my mood! On the development front appinventor.mit.edu is a very flexible (and brilliant and powerful) tool for novices to program android apps. I suspect that producing a working version yourself might have avoided many of your problems. I got into appinventor because I wanted to produce an app to monitor health symptoms, mood, activity etc at random times. (Mine has a gong not a ping.) I've sort of succeeded but, as often happens I think, I'm now using the app I made for something rather different, but am redesigning and extending the original idea.