A (hopefully measured) rant about sociobiology / pyschology / behavioural modelling, in response to an email on the SIMSOC list, rehashing themes covered on this blog:

This is probably a foolish venture (given my math ignorance) but here's some thoughts on an economic random walk. (Any pointers to elementary fuck-ups / blindingly obvious things I'm missing appreciated.) I've come across the graphs here in each of the simple models I've done of trade exchanges. This one isn't a real trade exchange - it's had price decisions removed entirely. So apart from the limit on the amount of money in the economy and the requirement that money is 'exchanged', they are random walks. It's like this. We start with:

• 100 people, 100 pounds each (so the amount of money in this 'economy' remains constant: the mean is always 100.)
• Run for 200,000 days
• On each day, each person randomly chooses someone, and gives them a pound if they have a pound to give. If they don't, on to the next person's random choice.

(See links below for graphs and code.)