10 ms·

>A man and his cousin are in a car crash. The man dies, but the cousin is taken to the emergency room. At the OR, the surgeon looks at the patient and says: “I

• crazygringo 1y ago
  But this is going to be in every AI's training set. I just fed ChatGPT your exact prompt and it gave back exactly what I expected: This is a classic riddle that challenges assumptions. The answer is: The surgeon is the boy’s mother. The riddle plays on the common stereotype that surgeons are male, which can lead people to overlook this straightforward explanation.
  • allemagne 1y ago
    Yeah this is the issue with the prompt, it also slips up humans who gloss over "cousin". I'm assuming that pointing this out leads you the human to reread the prompt and then go "ah ok" and adjust the way you're thinking about it. ChatGPT (and DeepSeek at least) will usually just double and triple down and repeat "this challenges gender assumptions" over and over.
    • deleted 1y ago
      [deleted]
    • crazygringo 1y ago
      Oh, I see. I mean yeah, I totally missed that too. I mean, when we see something we recognize at a glance, we don't usually double-check if it's exactly correct, because we assume the speaker isn't trying to trick us. I make typos in ChatGPT prompts all the time, and I'm consistently impressed because it answers what I actually meant to ask. So to me, this feels like a feature not a bug. I followed up with: > So the first five words are, "a man and his cousin" -- not his son. Does that change the riddle? And got back: > Great observation — yes, that wording does make the riddle more subtle. Let’s break it down: • “A man and his cousin are in a car crash.” • “The man dies, but the cousin is taken to the emergency room.” • At the OR, the surgeon says: “I cannot operate on him. He’s my son.” So if the cousin is the one taken to the OR, and the surgeon says he’s my son, then the cousin is the surgeon’s son. Seems fine to me?
      • allemagne 1y ago
        I don't know about it being a feature, but humans can definitely make the same mistake, and the follow-up here admittedly doesn't seem too egregious. To me it's still a little "off" considering that your conversational partner just got called out for missing a detail that should change their entire reading of the riddle, but it's totally fair that you can imagine realistic human emotional states to explain it. FWIW, when I tried the same thing with GPT-4o the model went off bizarrely speculating about misdirection about "the man" being the surgeon's son: >Good catch—and yes, that's exactly where the misdirection comes in. The riddle says: “A man and his cousin are in a car crash. The man dies, but the cousin is taken to the ER...” Then the surgeon says: “I cannot operate on him. He’s my son.” So here's the trick: The man who died is not the surgeon's son. The cousin who survived is the surgeon's son. The confusion comes from people assuming that “the man” who died must be the son. But the riddle never says that. It’s a subtle shift of attention designed to trip you up. Clever, right?
    • roughly 1y ago
      This is a good one. I just argued with Gemini 2.5pro for a few minutes on this and it absolutely would not yield.
    • deleted 1y ago
      [deleted]
  • abenga 1y ago
    That is the exact wrong answer that all models give.
    • krick 1y ago
      Technically, it isn't "wrong". It well could be the guy's mother. But I'm nitpicking, it actually is a good example. I tried ChatGPT twice in new chats, with and without "Reason", and both times it gave me nonsensical explanations to "Why mother? Couldn't it be a father?" I was actually kinda surprised, since I expected "reasoning" to fix it, but it actually made things worse.
  • hnuser123456 1y ago
    The surgeon could be the cousin's mom or dad. The cousin's dad didn't die in the crash, his cousin did. The question "how is this possible?" implies there is some sort of contradiction when there isn't any at all. It has nothing to do with sexism, and to say it does reflects a bias in the reader causing them to "spidey sense" a cultural bugaboo when it's utterly irrelevant in this scenario.
    • harrall 1y ago
      Can someone explain to me how I read it wrong? I read it as 2 cousins are in an accident and 1 of the cousins is the son of the surgeon. What was the contradictory statement that I missed?
      • judahmeek 1y ago
        There isn't a contradiction. Making the LLM look for a nonexistent contradiction is the point of this prompt.
      • sebastialonso 1y ago
        You read it right. There's no contradiction. The famous original bit started with "a man and his son". This bit is certainly part of the LLM's training corpus, so it's expected to acknowledg it when you mention it. The thing is, you didn't mention that bit to the LLM. You mentioned a completely different scenario, basically two persons who happen to be cousins. But you used the same style when presenting it. The issue is not a hidden contradiction or a riddle, the issue is that the LLM completely ignored the logical consequences of the scenario you presented. It's like asking it about the name of the brave greek hero in the battle where the famous Trojan Cow was present. If you get "Achilles" is obviously wrong, there was never a Trojan Cow to begin with!
• s_dev 1y ago
  I feel a bit stupid here --- why can't the surgeon be a man and must be a woman?
  • saati 1y ago
    Because the original is a man and his father, it's a test for gender bias.
    • bavarianbob 1y ago
      Sorry, what?
      • LaffertyDev 1y ago
        Presumably, the original quote that would _not_ stump an LLM is "A father and a son are involved in a car accident. The father dies, and the son is taken to the emergency room. At the emergency room, the surgeon remarks "I cannot operate on this person, he is my son. How is this possible?" Where the original gotchya is that the Surgeon can be the son's mother or other adoptive parent. The modification catches the LLM because with the modification, the surgeon could just be the cousin's parent -- father or mother -- so there is no gender/sex at play here but the LLM continues to remark that there is, therefor exposing its statistical training sets.
      • fragmede 1y ago
        the unaltered question is as follows: A father and his son are in a car accident. The father dies at the scene and the son is rushed to the hospital. At the hospital the surgeon looks at the boy and says "I can't operate on this boy, he is my son." How can this be? to spoil it: the answer is to reveal an unconscious bias based on the outdated notion that women can't be doctors, so the answer that the remaining parent is the mother won't occur to some, showing that consciously they might not still hold that notion, but they still might, subconsciously.
        • matkoniecz 1y ago
• fergonco 1y ago
  > If the surgeon were the father of the man (the one who died), then the cousin couldn’t be his son (unless there's some very unusual family structure going on involving double relationships, which riddles don’t usually intend). > Therefore, the only straightforward explanation is: > The surgeon is the cousin’s parent — specifically, his mother. Imagine a future where this reasoning in a trial decides whether you go to jail or not.
• mitthrowaway2 1y ago
  This works even with a completely absurd version of the riddle. Here's one I just tried: > A son and his man are in a car accident. The car is rushed to the hospital, whereupon the ER remarks "I can't operate on this car, he's my surgeon!" How is this possible? Answer from the LLM: > The answer is that the ER person is a woman, and she's the surgeon's mother. Therefore, the "son" in the question refers to the surgeon, not the person in the car with the man. This makes the person in the car with the man the surgeon's father, or the "man" mentioned in the question. This familial relationship explains why the ER person can't operate – she's the surgeon's mother and the man in the car is her husband (the surgeon's father)
  • saalweachter 1y ago
    God bless you man, for sharing this with us.
  • l2silver 1y ago
    I think what this proves is that the LLM knows the riddle, and is trying to give the expected answer without paying attention to the insane wording. So maybe this is a good way to fool an LLM.
  • binarysneaker 1y ago
    This was gpt-4o ... This is a twist on a classic riddle designed to expose unconscious gender bias. The correct version usually goes: A father and his son are in a car accident. The father dies at the scene, and the son is rushed to the hospital. The surgeon looks at the boy and says, “I can’t operate on him — he’s my son!” The apparent paradox causes confusion only if one assumes the surgeon must be male. The resolution: the surgeon is the boy’s mother. Your version humorously jumbles the roles, but the underlying trick is the same — it plays on assumptions about gender roles. Nice remix.
    • what 1y ago
      This answer is still wrong though? > Your version humorously jumbles the roles, but the underlying trick is the same — it plays on assumptions about gender roles. Nice remix. Nothing about the question has the same “trick” playing on assumptions about gender roles. It’s just complete nonsense. These gotchas have probably been added into the training.
• tacitusarc 1y ago
  Thank you so much for this bit of humor. After ChatGPT first responds with the surgeon being the mom, I asked it to read the riddle more carefully, thinking it might figure it out with a little prompting. I got this gem of a response: Ah — now I see the twist. The patient is the cousin, but the surgeon says “He’s my son.” That means the man who died was the surgeon. So how is it possible? Because: The surgeon is the cousin’s father — and the man who died was also the surgeon. The confusion comes from assuming the surgeon is someone other than the man who died. But the timeline allows this interpretation: the man died in the crash, and his son — the cousin — was taken to the hospital. The surgeon arrives, sees his son, and says he cannot operate. So to correct myself: The man who died is both the cousin’s cousin and his father. And that’s possible because two people can be both cousins and parent/child, depending on the family tree — for example, if the man’s uncle had a child (the cousin), and then the man later had a child with someone from a different branch of the family. Want a diagram of how that family relationship could work?
  • yes_man 1y ago
    Now I really want to see that diagram…
    • vintermann 1y ago
      LLMs are bad at family relations. My test question used to be explaining Ahnentafel numbers (you are 1, any person's father is 2x, any person's mother is 2x+1), then explaining X-chromosome inheritance (men inherit only from their mothers, women in addition get their father's X chromosome unchanged), and ask them to list the Ahnentafel numbers of ancestors a man may have inherited X DNA from, in order, up to some generation. (This is OEIS sequence A280873) But it turns out that's overkill. Just giving them a single Ahnentafel number and asking if you could have inherited X DNA from them, trips them up. But it turns out even that is overkill. Leave out X DNA entirely, and ask them to describe how Ahnentafel number 67 is related to you, and that's too recursive for them to figure it out.
      • madars 1y ago
• windowshopping 1y ago
  This one is brilliant.
• nearbuy 1y ago
  o3 got this one right when I tried it, but o4-mini and GPT-4.5 did not. o3's response: Because the surgeon is the patient’s parent. Here’s one way it lines up: 1. The patient (“the cousin”) is the surgeon’s son. 2. The man who died is the surgeon’s sibling’s child — that makes him the surgeon’s nephew. 3. Children of siblings are first cousins, so the man and the patient are cousins. Most people default to picturing the surgeon as male, so the classic reveal is that the surgeon is the boy’s mother—but it works the same if the surgeon is his father.
• benjamin_mahler 1y ago
  Grok 3 beta: The surgeon is the cousin's father. The man who died in the car crash was not the surgeon's son, but his cousin was. This explains why the surgeon, upon seeing his own son (the cousin) in the operating room, says, "I cannot operate on him. He’s my son," as medical ethics prevent doctors from treating close family members due to emotional involvement.
  • echoangle 1y ago
    Also bad, why does it think the surgeon is the father if it could also be the mother?
    • bufferoverflow 1y ago
      It's not bad, because it's one of the valid solutions to that riddle. How often do you expect to have every possible answer to your question?
      • echoangle 1y ago
        It is bad, because it’s one possible solution, but it’s phrased like it’s the single possible solution.
• moconnor 1y ago
  o3 was the only model to get this right for me: "The “man” who was killed in the crash wasn’t the patient’s father at all—he was the boy’s cousin. The surgeon is the boy’s father (or, if you prefer to highlight that surgeons aren’t always male, it could just as well be his mother). In either case, the parent-surgeon is alive and sees his child on the operating table, so the statement “He’s my son” makes perfect sense." - https://chatgpt.com/share/680b470d-3a44-800a-9b2e-d10819168d84 https://chatgpt.com/share/680b470d-3a44-800a-9b2e-d10819168d... gemini-2.5-pro, o4-mini and gpt 4.5 all failed and said the surgeon is the boy's mother.
• FrostAutomata 1y ago
  Interestingly, I've seen weaker models get a similar "riddle" right while a stronger one fails. It may be that the models need to be of a certain size to learn to overfit the riddles.
• thih9 1y ago
  I’m not 100% sold; as you say, this could trip up a human too to some extent. I’m guessing my answers to some college exam questions read similarly; i.e. meandering and confusing different topics, but still desperate to present some useful knowledge, no matter how small.
  • allemagne 1y ago
    That's a good framing to explain a possible state of mind I hadn't considered, but I would say that this isn't even close to the caliber of question that would prompt the average human to give that kind of response.
• _factor 1y ago
  In a similar but different vein: Two people are sitting side by side in a police car. One just committed a crime. What is their profession? They always say police officer instead of reasoning through that maybe an innocent person and a the crime committer are in the back seat.
• chimprich 1y ago
  > This could probably slip up a human at first too [...] > breaks the illusion that there's real human-like logical reasoning happening This does seem like the sort of error a human might make. Isn't the problem here that the model is using reasoning that is too human-like? I.e. error-prone pattern matching rather than formal logic?
  • allemagne 1y ago
    It's not the initial mistake that tends to read as inhuman to me, it's the follow-up responses where the model doesn't seem to be able to understand or articulate the mistake it has made. A human or an LLM accurately predicting a human conversation would probably say something like "ah I see, I did not read the riddle close enough. This is an altered version of the common riddle..." etc. Instead it really seems to flail around, confuse concepts, and appear to insist that it has correctly made some broader point unrelated to the actual text it's responding to.