6 ms·

As others have noted, every state in the state space will eventually be explored and so the appearance of convergence is a little misleading. Eventually the ric

by pontus 9y ago

As others have noted, every state in the state space will eventually be explored and so the appearance of convergence is a little misleading. Eventually the richest person will lose all the money and someone else will take that place. An interesting question is why we happen to see the system in such an unequal state when we look at it after e.g. 10000 iterations. The reason for this, I believe, is entropy. There are just vastly more ways to distribute the money unequally than equally (thinking of these as macro states). For example, there is only one (macro) state where everyone has $100, but there are 100! states where the money is distributed in a perfectly unequal way (e.g. 0, 1, 2, ..., 99, 5050 or any other way where all the people can be distinguished). So, if you randomly peek at the system at any given time it'd be very unlikely that you'd see it in any way other than a highly unequal state. To be fair, this argument neglects the dynamics (perhaps the transition probabilities to those states are sufficiently small that the n! multiplicity is watered down, although I suspect this is not the case.)

pishpash 9y ago
In this simulation, the amount of money you have does not affect how much you have to give away per round (until you get to $0, in which case you give away nothing) or how much you will get per round (until some people get to $0, in which case the money you get is less on average). So in most cases, with whatever you have, you are expected to see a gain distribution with zero mean. Since it's not a self correcting process other than at the $0 end, it's not surprising to see (1) a snapshot with uneven distribution, (2) no one dropping out permanently. Actually I don't know what is the point they are trying to make with this video. There is neither anything surprising in the general sense nor a solid statement about what is specifically seen.
- k__ 9y ago
  How would it change if it was 1% instead of $1?
  - spc476 9y ago
    I doubt it would change very much. I wrote a program a few years ago similar to this [1] and I tried several different amounts of "payment" (fixed and random) and each time the result was the same. What I did not track was the number of times a "person" became rich (for example, how many times a "person" had over 90% of the money) as that did not occur to me. [1] https://news.ycombinator.com/item?id=14282863 https://news.ycombinator.com/item?id=14282863
  - azza2110 9y ago
    I just ran it at 1% instead of $1. On only 5% of days was the spread greater than 80 -> 120.
    - lou1306 9y ago
      I went a little further and ran a simulation [^1] with random payments in the range from $1 to a fixed percentage of the payer's wealth. When this percentage is in the range 2-10%, the wealth inequality is significantly smaller than in the base case (i.e. all payments are $1). Then it starts growing again. [^1]: https://gist.github.com/lou1306/1041ed6cd4eed433cfabf45f666bf298 https://gist.github.com/lou1306/1041ed6cd4eed433cfabf45f666b...
- anigbrowl 9y ago
  The point is that it's counterintuitive even to intelligent people, and that matters because politics and economics are largely driven by the accumulation of intuitive decisions.
vinchuco 9y ago
>eventually can be a long time

by pontus 9y ago

pishpash 9y ago

In this simulation, the amount of money you have does not affect how much you have to give away per round (until you get to $0, in which case you give away nothing) or how much you will get per round (until some people get to $0, in which case the money you get is less on average). So in most cases, with whatever you have, you are expected to see a gain distribution with zero mean. Since it's not a self correcting process other than at the $0 end, it's not surprising to see (1) a snapshot with uneven distribution, (2) no one dropping out permanently. Actually I don't know what is the point they are trying to make with this video. There is neither anything surprising in the general sense nor a solid statement about what is specifically seen.

k__ 9y ago
How would it change if it was 1% instead of $1?
- spc476 9y ago
  I doubt it would change very much. I wrote a program a few years ago similar to this [1] and I tried several different amounts of "payment" (fixed and random) and each time the result was the same. What I did not track was the number of times a "person" became rich (for example, how many times a "person" had over 90% of the money) as that did not occur to me. [1] https://news.ycombinator.com/item?id=14282863 https://news.ycombinator.com/item?id=14282863
- azza2110 9y ago
  I just ran it at 1% instead of $1. On only 5% of days was the spread greater than 80 -> 120.
  - lou1306 9y ago
    I went a little further and ran a simulation [^1] with random payments in the range from $1 to a fixed percentage of the payer's wealth. When this percentage is in the range 2-10%, the wealth inequality is significantly smaller than in the base case (i.e. all payments are $1). Then it starts growing again. [^1]: https://gist.github.com/lou1306/1041ed6cd4eed433cfabf45f666bf298 https://gist.github.com/lou1306/1041ed6cd4eed433cfabf45f666b...
anigbrowl 9y ago
The point is that it's counterintuitive even to intelligent people, and that matters because politics and economics are largely driven by the accumulation of intuitive decisions.

vinchuco 9y ago

>eventually can be a long time