How readily can spreaders give up before the rumor stops reaching most of the crowd? At the default stifler-chance of 100 the rumor reaches only 3 to 7 people and the run stops within a dozen ticks, because each spreader tells one person and quits.
Try this Set stifler-chance to 10 and press Reset; the param is read every tick, but the run has usually stopped by then. The rumor now spreads through the crowd over about 200 ticks and reaches about 130 of the 140 people before the last spreader goes quiet.
About this model Where it ends up
A spatial version of Daley and Kendall's ignorant–spreader–stifler rumor model, in which people who keep meeting others who already know a rumor stop spreading it. Here people wander a torus and only talk to those within a few patches, and the rumor's reach turns on how readily spreaders give up.
Setup scatters population people and makes the first initial-spreaders of them spreaders. Each tick, each person steps forward 1 with a small random turn at move-chance percent. Then every spreader with an ignorant person within meeting-radius tells one of them, who becomes a spreader, and if anyone informed is within meeting-radius it becomes a stifler at stifler-chance percent. The run stops when no spreaders are left. population and initial-spreaders apply at Reset; the other params are read every tick.
Two quirks of this version make spreaders quit sooner than in the classic model. A spreader counts the person it has just told as informed, so at stifler-chance 100 it stops after its first telling. And a telling is undone at the end of the tick when the listener's own turn came first, which happens about half the time. NetLogo's Rumor Mill, which this is named after, is a different model: people on patches pass the rumor to random neighbors and never stop.
