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There's a similar effect when waiting for a bus or other public transport. At first, the expected time you'll have to wait exhibits decreases as time goes by: i
by dmurray 9y ago
There's a similar effect when waiting for a bus or other public transport. At first, the expected time you'll have to wait exhibits decreases as time goes by: if there's a bus every 10 minutes, after waiting 8 minutes you expect one to arrive in 1 minute, compared to 5 when you started waiting. Stand there longer without a bus arriving, however, and the Lindy effect starts to apply. After 15 minutes without a bus, most likely the bus broke down, but you can expect another within 5 minutes. After 30 minutes, well, maybe the drivers are on strike today or this bus route got cancelled or you misremembered the frequency of the bus - either way, expect to keep waiting.
Anyone know of a term for this kind of behaviour? I've never seen it named, though I do recall an article that made the HN front page that demonstrated this effect with the New York subway.
- gwern 9y agoThe Hope Function? https://www.gwern.net/docs/statistics/1994-falk https://www.gwern.net/docs/statistics/1994-falk
- dmurray 9y agoYes, this is it exactly! Even the framing of it as waiting for a bus is given as one of the examples, "Problem 2, The Standard Wait Problem" but the other examples also have similar behaviour.
- QAPereo 9y agoHeuristics? It seems like a rough heuristic way to find a likely path.
- gerdesj 9y agoYou seem to be assuming that given you have waited for eight minutes already and that the schedule is 10 minutes that therefore half of the period remaining is the expected time for the bus. That seems like a fair heuristic but I'd personally read the timetable. To get a more exact answer you also need to know the distribution of actual bus arrival times. If they turn up at your stop every 10 mins (mean) but with a standard deviation of say two minutes then your heuristic is not the best. Far more interesting is that two of the buggers will always turn up when you don't actually need one. I can prove that by assertion now and fairly confidently be able to appeal to around 60M Britons for testimony as required. This is not related to "virality" which is my newly made up term for the Lindy Effect.
- Feuilles_Mortes 9y agoYou might be interested in queuing theory: https://en.wikipedia.org/wiki/Queueing_theory https://en.wikipedia.org/wiki/Queueing_theory
- throwawaybbq1 9y agoWell .. if you take hope and mistakes out of the equation, I think this is the memoryless property?
- sdrothrock 9y agoOne type of cause for this behavior is the sunk cost fallacy, or more broadly, escalation of commitment: https://en.wikipedia.org/wiki/Escalation_of_commitment https://en.wikipedia.org/wiki/Escalation_of_commitment
- todd8 9y agoIf buses arrive uniformly every 10 minutes and you arrive at a random time, your wait on average will be 5 minutes. However, if the buses arrive independently and by a purely random process on average every 10 minutes (i.e. a poisson process), your wait will average 10 minutes. I always remember this result from probability when waiting for something. It helps me feel less unlucky: of course, I tell myself, it's more likely to land in the time interval between widely spaced busses because those intervals take up more space on the timeline.