Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Heuristics that almost always work

astralcodexten.substack.com

Post reply on HN
Print view View original

151–160 of 541 posts

Re: Heuristics that almost always work

#151

Post by anter »

kqr wrote: post #44
kbuchanan wrote: post #35

Earlier quoted context omitted.

It's a great example. This is the very reason I have scaled back the amount of time I rock climb as I've gotten older -- not because any individual outing is dangerous, but there's an element of Russian roulette wherein the mere act of doing it more often dramatically changes the risk.

Also known as the Kelly criterion. If one possible outcome of an action is associated with a great enough loss, it doesn't make sense to perform the action no matter how unlikely the loss.

If anyone wants to play around with an interactive explanation of the The Kelly criterion: https://explore.paulbutler.org/bet/

Re: Heuristics that almost always work

#152

Post by vincentmarle »

kbuchanan wrote: post #35
inglor_cz wrote: post #30

This story reminded me of a story written by a Czech biologist who studied animals in Papua-New Guinea and went to a hunt with a group of local tribesmen. The dusk was approaching, they were still in the forest and he proposed that they could sleep under a tree. The hunters were adamant in their refusal: no, this is dangerous, a tree might fall on you in your sleep and kill you . He relented, but silently considered…

It's a great example. This is the very reason I have scaled back the amount of time I rock climb as I've gotten older -- not because any individual outing is dangerous, but there's an element of Russian roulette wherein the mere act of doing it more often dramatically changes the risk.

This is called ergodic theory, the more you repeat an action that could result in catastrophe, the likelihood of that catastrophe occuring will be close to 100% if the number of events is high enough.

Re: Heuristics that almost always work

#153

Post by ska »

moralestapia wrote: post #122
pessimizer wrote: post #108

Earlier quoted context omitted.

If you'll die if a roll of three dice comes up sixes, you're not really in a lot of danger. If you do it every day, you have about 15 months to live.

>you have about 15 months to live Or a few minutes ... or 20 years. That's the thing w/ statistically independent trials.

That's like the difference between

You could win 100mm in the lottery (true statement!)

Lottery tickets are a good investment (almost always, false statement).

Planning on "well it could happen, technically" isn't a good approach.

Re: Heuristics that almost always work

#155

Post by pessimizer »

alexfrydl wrote: post #145
the_af wrote: post #72

One interesting twist on the doctor example: we know she is almost always right that it's nothing, that it will all go away and that just two aspirins are ok. The article correctly points out that she will miss one or two cases where it was a terrible disease instead, and that her prescription of aspirin and to go away and rest will be misguided. However... doctors must do more than just cure you. They must also "do…

The problem is that people are not statistics. It may sound reasonable on the surface to say that this heuristic minimizes harm on average because she doesn't perform unnecessary interventions on the 99.9%. However, there are still actual human beings in the 0.1% who are harmed. What you're really saying is that if a group of people is small enough, it's fair for them to suffer preventable harm if preventing it would…

You have no way to know if you're in the 0.1%. It's not written on your body anywhere. So if an early test can save 1/1000 from dying, but the false positives from an early test kill 3/1000, false positives are more dangerous than the disease you may or may not have.

Re: Heuristics that almost always work

#156

Post by derbOac »

kbuchanan wrote: post #35
inglor_cz wrote: post #30

This story reminded me of a story written by a Czech biologist who studied animals in Papua-New Guinea and went to a hunt with a group of local tribesmen. The dusk was approaching, they were still in the forest and he proposed that they could sleep under a tree. The hunters were adamant in their refusal: no, this is dangerous, a tree might fall on you in your sleep and kill you . He relented, but silently considered…

It's a great example. This is the very reason I have scaled back the amount of time I rock climb as I've gotten older -- not because any individual outing is dangerous, but there's an element of Russian roulette wherein the mere act of doing it more often dramatically changes the risk.

"There are bold X, and old X, but no old, bold X."

Replace X with any practitioners subject to sufficient risk as a result of their practice.

I first heard it in the context of mushroom foraging.

Re: Heuristics that almost always work

#157

Post by jrochkind1 »

twobitshifter wrote: post #136
aaronblohowiak wrote: post #100

Earlier quoted context omitted.

but the risk is independent. so once you do the N+1 time safely, you are back to N and your next time is _also_ just an N+1.

True but it would be incorrect to assume that you can safely keep basejumping every day in a year, just because you haven’t died in the last 50 days. Eventually the stats say you will be 87% likely to have an accident when you consider your choice at the beginning of the year. It might be day 20 or day 300, but you won’t know what case you end up in. The chance of your next jump being your last is always the same, bu…

Not exactly. If you've done it 50 days without an accident, your current chances of the accident happening in the remainder of the year are NOW less than 87%.

If you've made it Jan 1 to July 1 months without an accident, the chances of you making it to Dec 31 are now better than they were on Jan 1 -- because now they are just the chances of you making it six months, not a year.

The chances of flipping 6 heads in a row are 1/64. But if I've already flipped 3 in a row... the chances of flipping three _more_ heads in a row is 1/8, the same as always for flipping 3 heads in a row. The ones that already happened don't effect your future chances.

Re: Heuristics that almost always work

#158

Post by Stronico »

aaronblohowiak wrote: post #100
HPsquared wrote: post #82

Earlier quoted context omitted.

The "slippery slope" principle applies here though: N+1 enables N+2, which enables N+3 and so on.

but the risk is independent. so once you do the N+1 time safely, you are back to N and your next time is _also_ just an N+1.

Risk is independent of prior events, habits are not - I think that was what the anthropologist story is about
Post reply on HN