An interesting side effect in my machine-learning project

I was doing some follow-up on my mini-machine learning project.  I put out some caveats in that post so I won't repeat them here. Basically the project was sketchy enough and premature enough that I'd advise taking a grain of salt or three here.

In this look, I had noticed in the data that at higher levels of wealth at some time t, the machine liked lower spend rates (we'd only looked at W(t)=$1M by the way).  That was counter-intuitive to me since I feel like I'm personally closer to "the edge" than I'd prefer and I feel like if I had more $ I'd perhaps loosen up a bit in both absolute and relative terms. But the machine is the machine and we obey the machine in our dystopian sci-fi ret-fin world. Let's look at what he/she is telling us.


I'll just report what the machine was telling me and get on with it.  I've limited the wealth interval here since it was tedious to produce some of the charts and the data is sketch anyway.

1. 2D chart of age vs spend rate with the lines representing level of W at time t (age).

2. Same chart rendered as a heat map: x=age, y=W, color=rate

3. Same chart rendered as a surface: x=age,y=W, z=rate (colors don't relate chart to chart)

Discussion

The machine seems to think that at higher levels of wealth that the capacity for spend "rates" is lower and that at later ages that differentiation, while still present, is not as intense. This seemed counter-intuitive to me.  My guess, my hypothesis, which is untested and unexplored, is that at higher levels of wealth the absolute dollars spent at any particular rate are in absolute terms a lot higher than the absolute level of subsistence...to which it crashes if wealth depletes. Because the utility math is convex that means the crash (in consumption) is probably penalized, in relative terms now, a LOT more than at the lower absolute spends. So, it looks like the machine doesn't like that.  Especially, it seems, in the early years when there are a lot of years left in the retirement i.e., where a long crash-state would suck and suck more the more you lose in consumption-capacity terms.  The machine is probably not as dumb as I think it is.  TBD though. This is just a guess. Not really sure of what's going on inside the black box yet.