Yesterday I noticed a mistake in my reasoning that seems to be due to a cognitive bias, and I wonder how widespread or studied it is, or if it has a name—I can’t think of an obvious candidate.
I was leaving work, and I entered the parking elevator in the lobby and pressed the button for floor −4. Three people entered after me—call them A, B and C - but because I hadn’t yet turned around to face the door, as elevator etiquette requires, I didn’t see which one of them pressed which button. As I turned around and the doors started to close, I saw that −2 and −3 were lit in addition to my −4. So, three floors and four people, means two people will come out on one of the floors, and I wondered which one it’ll be.
The elevator stopped at floor −2. A and B got out. Well, I thought, so C is headed for −3, and I for −4 alone. As the doors were closing, B rushed back and squeezed through them. I realized she didn’t want −2, and went out of the elevator absent-mindedly. I wondered which floor she did want. The elevator went down to −3. The doors opened and B got out… and then something weird happened: C didn’t. I was surprised. Something wasn’t right in my idle deductions. I figured it out in the few seconds it took for the elevator to descend to my floor and let me out together with C.
Where did I go wrong? When I knew that B left on −2, I deduced, correctly, that C will get out on −3. But then B came back; the fact of her leaving on −2 turned out to be wrong; yet I didn’t cancel my deduction about C and didn’t return him the “freedom” of leaving either on −3 or on −4. It didn’t even occur to me to do that. Why didn’t it?
It seems important that the new information was a correction of a known fact, and not just some other fact. If I treat the new information “B does not leave at −2” purely as a fact, the consequence for C is “C may leave either on −3 or on −4“, which is already clear as it is and not worth updating. No, it seems “B does not leave at −2” has a special character when it comes to correct the previously-assumed “B left at −2”. It comes as a “rollback” of existing information and I need to “roll back” everything I deduced from that information. And that seems hard to do and easy to forget. So if wasn’t just a failure to update that I committed. It was a failure to “roll back”.
On reflection, this mistake seems like something we might be doing often, and something to keep an eye out for. Is there a name for this mistake, has it been studied?
Seems related to the studies where people are told a fact, but it’s in red, which they’re told means it’s not true. After seeing lots of different facts in colours blue or red (blue means true) they’re asked about certain facts, and they’re more likely to remember a false fact as true than a true fact as false—we’re more likely to believe things, and don’t tend to take on contrary evidence as easily.
Thanks. Cached thoughts seem applicable, but also too broad for what I’m describing. After all, if I failed to update on A and B exiting on −2, and continued thinking C may get out either on −3 or −4, that could also be described as a cached thought which I retained even when new evidence contradicted it. But I didn’t do that, and was in no danger on doing that. I think that it’s the necessity to roll back to the previous state, rather than just, in general, update on new evidence and get rid of the cached thought, that seems important here.
This post is very interesting. It reminds me very much of some variations of the change scam. You seem to be describing something really similar, the rollback of information you speak of is applicable to the counting of change. I also feel like this sort of mistake happens often but I might not notice it. I feel like this deserves a name like rollback deduction failure or something.
Seems a bit Monty Hall-ish. You updated when B got out on 2 but didn’t retract your update when B re-entered. After your update, C—or maybe you were thinking “the remainder of strangers on this elevator”—had near certain chance of getting out on 3 so when B came back in it looks like you mashed the two together as “the remainder of strangers on this elevator”.
I have no clue if this phenomenon has a name or not.
Yesterday I noticed a mistake in my reasoning that seems to be due to a cognitive bias, and I wonder how widespread or studied it is, or if it has a name—I can’t think of an obvious candidate.
I was leaving work, and I entered the parking elevator in the lobby and pressed the button for floor −4. Three people entered after me—call them A, B and C - but because I hadn’t yet turned around to face the door, as elevator etiquette requires, I didn’t see which one of them pressed which button. As I turned around and the doors started to close, I saw that −2 and −3 were lit in addition to my −4. So, three floors and four people, means two people will come out on one of the floors, and I wondered which one it’ll be.
The elevator stopped at floor −2. A and B got out. Well, I thought, so C is headed for −3, and I for −4 alone. As the doors were closing, B rushed back and squeezed through them. I realized she didn’t want −2, and went out of the elevator absent-mindedly. I wondered which floor she did want. The elevator went down to −3. The doors opened and B got out… and then something weird happened: C didn’t. I was surprised. Something wasn’t right in my idle deductions. I figured it out in the few seconds it took for the elevator to descend to my floor and let me out together with C.
Where did I go wrong? When I knew that B left on −2, I deduced, correctly, that C will get out on −3. But then B came back; the fact of her leaving on −2 turned out to be wrong; yet I didn’t cancel my deduction about C and didn’t return him the “freedom” of leaving either on −3 or on −4. It didn’t even occur to me to do that. Why didn’t it?
It seems important that the new information was a correction of a known fact, and not just some other fact. If I treat the new information “B does not leave at −2” purely as a fact, the consequence for C is “C may leave either on −3 or on −4“, which is already clear as it is and not worth updating. No, it seems “B does not leave at −2” has a special character when it comes to correct the previously-assumed “B left at −2”. It comes as a “rollback” of existing information and I need to “roll back” everything I deduced from that information. And that seems hard to do and easy to forget. So if wasn’t just a failure to update that I committed. It was a failure to “roll back”.
On reflection, this mistake seems like something we might be doing often, and something to keep an eye out for. Is there a name for this mistake, has it been studied?
Seems related to the studies where people are told a fact, but it’s in red, which they’re told means it’s not true. After seeing lots of different facts in colours blue or red (blue means true) they’re asked about certain facts, and they’re more likely to remember a false fact as true than a true fact as false—we’re more likely to believe things, and don’t tend to take on contrary evidence as easily.
http://wiki.lesswrong.com/wiki/Cached_thought http://lesswrong.com/lw/k5/cached_thoughts/
Thanks. Cached thoughts seem applicable, but also too broad for what I’m describing. After all, if I failed to update on A and B exiting on −2, and continued thinking C may get out either on −3 or −4, that could also be described as a cached thought which I retained even when new evidence contradicted it. But I didn’t do that, and was in no danger on doing that. I think that it’s the necessity to roll back to the previous state, rather than just, in general, update on new evidence and get rid of the cached thought, that seems important here.
This post is very interesting. It reminds me very much of some variations of the change scam. You seem to be describing something really similar, the rollback of information you speak of is applicable to the counting of change. I also feel like this sort of mistake happens often but I might not notice it. I feel like this deserves a name like rollback deduction failure or something.
Change blindness seems related.
Seems a bit Monty Hall-ish. You updated when B got out on 2 but didn’t retract your update when B re-entered. After your update, C—or maybe you were thinking “the remainder of strangers on this elevator”—had near certain chance of getting out on 3 so when B came back in it looks like you mashed the two together as “the remainder of strangers on this elevator”.
I have no clue if this phenomenon has a name or not.