OpenAI Fixes ChatGPT's Em-Dash Problem, Raising Questions About AI Control

Forget AGI -- Sam Altman celebrates ChatGPT finally following em-dash formatting rules

Em-dashes have become what many believe to be a telltale sign of AI-generated text over the past few years. The punctuation mark appears frequently in outputs from ChatGPT and other AI chatbots, sometimes to the point where readers believe they can identify AI writing by its overuse alone -- although human writers can overuse it too. On Thursday evening, OpenAI CEO Sam Altman posted on X that ChatGPT has started following custom instructions to avoid using em-dashes. "Small-but-happy win: If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do!" he wrote. The post, which came two days after the release of OpenAI's new GPT-5.1 AI model, received mixed reactions from users who have struggled for years with getting the chatbot to follow specific formatting preferences. And this "small win" raises a very big question: If the world's most valuable AI company has struggled with controlling something as simple as punctuation use after years of trying, perhaps what people call artificial general intelligence (AGI) is farther off than some in the industry claim. "The fact that it's been 3 years since ChatGPT first launched, and you've only just now managed to make it obey this simple requirement, says a lot about how little control you have over it, and your understanding of its inner workings," wrote one X user in a reply. "Not a good sign for the future." While Altman likes to publicly talk about AGI (a hypothetical technology equivalent to humans in general learning ability), superintelligence (a nebulous concept for AI that is far beyond human intelligence), and "magic intelligence in the sky" (his term for AI cloud computing?) while raising funds for OpenAI, it's clear that we still don't have reliable artificial intelligence here today on earth. But wait, what is an em-dash anyway, and why does it matter so much? AI models love em-dashes because we do Unlike a hyphen, which is a short punctuation mark used to connect words or parts of words, that lives with a dedicated key on your keyboard (-), an em-dash is a long dash denoted by a special character ( -- ) that writers use to set off parenthetical information, indicate a sudden change in thought, or introduce a summary or explanation. Even before the age of AI language models, some writers frequently bemoaned the overuse of the em-dash in modern writing. In a 2011 Slate article, writer Noreen Malone argued that writers used the em-dash "in lieu of properly crafting sentences" and that overreliance on it "discourages truly efficient writing." Various Reddit threads posted prior to ChatGPT's launch featured writers either wrestling over the etiquette of proper em-dash use or admitting to their frequent use as a guilty pleasure. In 2021, one writer in the r/FanFiction subreddit wrote, "For the longest time, I've been addicted to Em Dashes. They find their way into every paragraph I write. I love the crisp straight line that gives me the excuse to shove details or thoughts into an otherwise orderly paragraph. Even after coming back to write after like two years of writer's block, I immediately cram as many em dashes as I can." Because of the tendency for AI chatbots to overuse them, detection tools and human readers have learned to spot em-dash use as a pattern, creating a problem for the small subset of writers who naturally favor the punctuation mark in their work. As a result, some journalists are complaining that AI is "killing" the em-dash. No one knows precisely why LLMs tend to overuse em-dashes. We've seen a wide range of speculation online that attempts to explain the phenomenon, from noticing that em-dashes were more popular in 19th-century books used as training data (according to a 2018 study, dash use in the English language peaked around 1860 before declining through the mid-20th century) or perhaps AI models borrowed the habit from automatic em-dash character conversion on the blogging site Medium. One thing we know for sure is that LLMs tend to output frequently seen patterns in their training data (fed in during the initial training process) and from a subsequent reinforcement learning process that often relies on human preferences. As a result, AI language models feed you a sort of "smoothed out" average style of whatever you ask them to provide, moderated by whatever they are conditioned to produce through user feedback. So the most plausible explanation is still that requests for professional-style writing from an AI model trained on vast numbers of examples from the Internet will lean heavily toward the prevailing style in the training data, where em-dashes appear frequently in formal writing, news articles, and editorial content. It's also possible that during training through human feedback (called RLHF), responses with em-dashes, for whatever reason, received higher ratings. Perhaps it's because those outputs appeared more sophisticated or engaging to evaluators, but that's just speculation. From em-dashes to AGI? To understand what Altman's "win" really means, and what it says about the road to AGI, we need to understand how ChatGPT's custom instructions actually work. They allow users to set persistent preferences that apply across all conversations by appending written instructions to the prompt that is fed into the model just before the chat begins. Users can specify tone, format, and style requirements without needing to repeat those requests manually in every new chat. However, the feature has not always worked reliably because LLMs do not work reliably (even OpenAI and Anthropic freely admit this). A LLM takes an input and produces an output, spitting out a statistically plausible continuation of a prompt (a system prompt, the custom instructions, and your chat history), and it doesn't really "understand" what you are asking. With AI language model outputs, there is always some luck involved in getting them to do what you want. In our informal testing of GPT-5.1 with custom instructions, ChatGPT did appear to follow our request not to produce em-dashes. But despite Altman's claim, the response from X users appears to show that experiences with the feature continue to vary, at least when the request is not placed in custom instructions. So if LLMs are statistical text-generation boxes, what does "instruction following" even mean? That's key to unpacking the hypothetical path from LLMs to AGI. The concept of following instructions for a LLM is fundamentally different from how we typically think about following instructions as humans with general intelligence, or even a traditional computer program. In traditional computing, instruction following is deterministic. You tell a program "don't include character X," and it won't include that character. The program executes rules exactly as written. With LLMs, "instruction following" is really about shifting statistical probabilities. When you tell ChatGPT "don't use em-dashes," you're not creating a hard rule. You're adding text to the prompt that makes tokens associated with em-dashes less likely to be selected during the generation process. But "less likely" isn't "impossible." Every token the model generates is selected from a probability distribution. Your custom instruction influences that distribution, but it's competing with the model's training data (where em-dashes appeared frequently in certain contexts) and everything else in the prompt. Unlike code with conditional logic, there's no separate system verifying outputs against your requirements. The instruction is just more text that influences the statistical prediction process. When Altman celebrates finally getting GPT to avoid em-dashes, he's really celebrating that OpenAI has tuned the latest version of GPT-5.1 (probably through reinforcement learning or fine-tuning) to weight custom instructions more heavily in its probability calculations. There's a grand irony about control here: Given the probabilistic nature of the issue, there's no guarantee the issue will stay fixed. OpenAI continuously updates its models behind the scenes, even within the same version number, adjusting outputs based on user feedback and new training runs. Each update arrives with different output characteristics that can undo previous behavioral tuning, a phenomenon researchers call the "alignment tax." Precisely tuning a neural network's behavior is not yet an exact science. Since all concepts encoded in the network are interconnected by values called weights, adjusting one behavior can alter others in unintended ways. Fix em-dash overuse today, and tomorrow's update (aimed at improving, say, coding capabilities) might inadvertently bring them back, not because OpenAI wants them there, but because that's the nature of trying to steer a statistical system with millions of competing influences. This gets to an implied question we mentioned earlier. If controlling punctuation use is still a struggle that might pop back up at any time, how far are we from AGI? We can't know for sure, but it seems increasingly likely that it won't emerge from a large language model alone. That's because AGI, a technology that would replicate human general learning ability, would likely require true understanding and self-reflective intentional action, not statistical pattern matching that sometimes aligns with instructions if you happen to get lucky. And speaking of getting lucky, some users still aren't having luck with controlling em-dash use outside of the "custom instructions" feature. Upon being told in-chat to not use em-dashes within a chat, ChatGPT updated a saved memory and replied to one X user, "Got it -- I'll stick strictly to short hyphens from now on."

OpenAI says it's fixed ChatGPT's em dash problem | TechCrunch

OpenAI says ChatGPT will now ditch the em dashes if you tell it to. The telltale sign that supposedly signals text written by AI has popped up everywhere in recent months, including in school papers, emails, comments, customer service chats, LinkedIn posts, online forums, ad copy, and more. The inclusion of the em dash has led people to criticize those writers for being lazy and turning to an AI chatbot to do their work. Of course, many have also argued for the em dash, saying it's been a part of their writing well before LLMs adopted the punctuation. However, the fact that chatbots couldn't seem to avoid its use made the so-called "ChatGPT hyphen" a newly objectionable addition to any text, even if they weren't a reliable signal of content created by generative AI. The problem had stumped OpenAI for some time, as ChatGPT users were unable to get the chatbot to stop using the symbol, even when they specifically asked it not to. Now, OpenAI CEO Sam Altman says the company has fixed the problem. In a post on X, Altman writes, "If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do," calling the update a "small-but-happy win." The company explains in a post on Threads (where it forced ChatGPT to apologize for "ruining the em dash") that ChatGPT will be better at not using the em dash if you instruct it not to via the custom instructions in your personalization settings. That means it won't necessarily eliminate the em dash from its output by default, but you will at least have more control over the frequency of its appearance.

You Can Now Stop ChatGPT's Em-Dash Fixation: Here's How

Don't miss out on our latest stories. Add PCMag as a preferred source on Google. If you've been sneakily trying to use AI for writing, or have been in a position where you had to check for it, you'll know that the em-dash is one of the most famous signs of ChatGPT-generated writing. Research from The Washington Post showed that at one point this year almost half of ChatGPT-generated responses included the controversial piece of punctuation, up almost fivefold compared to 2024. Meanwhile, many ChatGPT users took to social media to complain about the trouble they were having getting the chatbot to stop using em-dashes, despite trying many different prompts to that end. Now, OpenAI has stepped in to fix the em-dash issue. According to CEO Sam Altman, users can now customize their settings not to use em-dashes going forward (and it will actually stop using them). To make the switch, head to ChatGPT's custom instructions by clicking on your profile icon in the bottom-left or top-right of the screen. Then select Settings or Customize ChatGPT, followed by Custom Instructions. ChatGPT's em-dash fixation has proven controversial since it first started to appear. Many within the writing community have pointed out that the software quirk has put some writers in a difficult position, as em-dashes are now associated with AI writing rather than their own efforts. Other ChatGPT users on social media have said they simply don't use them now to avoid unfair accusations. OpenAI never explained why ChatGPT developed such a fondness for the em-dash in the first place, but a few theories have emerged. Ars Technica, which covered the news, pointed to research that suggests it's because the em-dash was very common in 19th-century books before falling out of favour in the 20th century. LLMs often use these types of books as training data, as they are mostly in the public domain and won't provoke any copyright lawsuits. Other theories have pointed towards the widespread use of em-dashes on Medium blogs, which are a common source of OpenAI's training data. Though it's fairly simple to point to obvious punctuation choices like the em-dash as examples of AI-generated writing, AI's detectability may run far deeper. A recent paper from the University of Zurich, University of Amsterdam, Duke University, and New York University found that if properly prompted, LLMs can effectively emulate the more mechanistic aspects of social media posts, such as sentence length, but still fall short of choosing believable emotional tone, often appearing overly positive in posts generated for platforms like X or Bluesky. The jury is still out on whether OpenAI's new fix will work for everyone, however. Ars pointed to a response to Altman's announcement on X, where ChatGPT responded to a command never to use em-dashes with an em dash in the reply.

OpenAI says ChatGPT will listen if you tell it not to use em dashes

You may now have to scrutinize what you read on the internet (and event on print) more closely to determine if it's the product of AI. Sam Altman has revealed on X that if you tell ChatGPT not to use em dashes in your custom instructions, the chatbot will now finally listen to you. Previously, ChatGPT would ignore your instruction and continue using em dashes even if you tell it not to. People are treating the presence of em dashes, especially if they're used in abundance, as one of the biggest tells if something was written by large language models. Of course, just because a piece of text uses em dashes doesn't mean it was actually written by AI, but people have become suspicious of any writing that uses the punctuation mark. It's not quite clear while generative AI models have the tendency to pepper the text they generate with em dashes. LLMs are trained on a vast number of books and online content, such as scientific papers, posts on public forums and articles like this. It's possible that punctuation mark appears so often in training materials and isn't flagged by AI trainers as something that the LLM should avoid using.

ChatGPT Achieves a New Level of Intelligence: Not Using the Em Dash

OpenAI has not achieved its goal of developing a superintelligence or artificial general intelligence, nor has it cracked its planned construction of an autonomous "AI researcher." But it has figured out how to get ChatGPT to stop misusing the em dash. So, that's something. In a post on X, CEO Sam Altman announced, "If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do!" He called the development a "small-but-happy win." The company confirmed the capability to cut off the chatbot's reliance on the punctuation mark in a post on Threads, where it made ChatGPT write a formal apology for "ruining the em dash." Notably, the chatbot was not able to write the apology without using an em dash. To that point, it seems like there's a noteworthy distinction to be made here. OpenAI has not figured out how to get ChatGPT to use the em dash in a more appropriate manner or to deploy it more sparingly by default. Instead, it has simply given users the ability to tell ChatGPT not to use it, a change that can be made within the chatbot's personalization settings. That ability follows the release of GPT-5.1, the latest model from OpenAI. One of the primary points of improvement that the company hammered in its rollout of the new model was the fact that GPT-5.1 is apparently better at following instructions and offers more personalization features. So the em dash clampdown appears to just be one example of how users can make use of the model's more compliant sensibilities rather than some fix to the underlying model's overall output. The fact that the em dash fix is something that has to happen on a user-by-user basis probably speaks to just how much of a black box most LLMs are. In fact, there are users in Altman's replies on X showing that, despite the instruction, their instance of ChatGPT continues to spit out em dashes. OpenAI's presentation of personalization as a solve would seem to suggest that finding a solution at scale is still really, really hard. The company has seemingly figured out a way to weight custom instructions more heavily within its calculations when producing a response to a prompt, which can produce a result like a person's version of ChatGPT no longer using em dashes. But it still seems like the company can't figure out why the problem happened in the first place or persists. No wonder the company is leaning heavily into personalization and talking less about AGI lately.

OpenAI has fixed ChatGPT's infamous 'em dash' obsession (somewhat)

The "em dash" is seen by some as a dead giveaway of AI-generated text, mainly because ChatGPT loves to use it. OpenAI CEO Sam Altman shared in a social media post that the company has now fixed ChatGPT's overuse of the "em dash," which is the extra-long hyphen that's commonly seen in AI-generated text. In the past, ChatGPT was overzealous in its use of the em dash, to the point where it'd continue to include them even when users asked it not to. Now, with the fix, a user can instruct ChatGPT to not use em dashes and it will respect the instruction. "Small-but-happy win," Altman writes in his post. "If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do!" ChatGPT will continue to use em dashes per usual if no instruction is given. That part hasn't changed. The AI chatbot's fondness for the em dash has been so prevalent in its responses that many have (misguidedly) begun to see it as a surefire sign that a text was generated using an AI tool.

ChatGPT Will Stop Using Em Dashes If Instructed So | AIM

Sam Altman, OpenAI's CEO, stated on X that ChatGPT will refrain from using em dashes when a user specifies this preference in their Custom Instructions. "It finally does what it's supposed to do," he said. Custom instructions on ChatGPT allow tailoring how the AI responds and can be found in the Personalisation tab in the settings menu. "Small-but-happy win," Altman added. Ever since ChatGPT gained popularity among the masses, the em dash, or ' -- ', has appeared with increasing frequency in online writing, becoming a noticeable hallmark of AI-generated text. Users have since found it difficult to instruct ChatGPT to avoid using em dashes in a piece of text. "I pushed, pulled, rewired and begged, but nothing made it stop," one user wrote in a blog post. "$100 for anyone who can show me how to get ChatGPT to stop using em dashes. It's driving me insane," said Chip Huyen, the author of the popular book 'AI Engineering', in a post on X a few months ago. Multiple factors have been attributed to ChatGPT's increasing use of em dashes. The model reflects patterns present in its training data, which includes a significant amount of modern prose that relies on the mark for pacing, emphasis and fluid transitions. "If [AI] relied a lot on either magazine writing or blog writing, then those two styles were quite fond of the em dash," said Aileen Gallagher, a journalism professor at Syracuse University, in a statement to the Washington Post earlier this year. Em dashes also offer a compact way to connect or interrupt ideas without additional structure, making them efficient from a token-generation standpoint. The excess usage of em dashes in ChatGPT has also been a subject of jokes and memes on social media. Some also say that this correlation is unfair. "It's annoying that em dashes have become the telltale sign someone used ChatGPT to generate the text," said one user on X. "I use them often in my emails and writing -- probably incorrectly. Now everyone assumes I'm putting everything through ChatGPT." Altman announced this update a day after OpenAI released the GPT 5.1 model. It is an upgrade to the GPT-5 model family that introduces new reasoning features, faster performance on simple tasks, and expanded personalisation tools across ChatGPT.

ChatGPT's tiny switch signals a big shift in AI writing

In a subtle yet telling update, OpenAI's ChatGPT now lets users turn off the em-dash by using its custom instructions. That punctuation mark, once a giveaway of AI-generated text, has been quietly de-weaponised. This change reflects a broader move toward a more personalised writing style and control, and it matters for writers, students, content creators and businesses that use generative AI. In the evolving landscape of generative-AI writing, even the smallest details can carry outsized weight. Enter the em-dash: a long punctuation mark that became a quiet but persistent signature of AI-written prose. With the latest update to ChatGPT, that tell-tale piece of punctuation may finally be optional. For some time now, writers, educators and even internet commentators have flagged the em-dash as a "tell" of AI-generated text. Because ChatGPT and similar systems tended to pepper their output with em-dashes, human readers began to pick up on the pattern. While many writers embraced the em-dash as a tool of rhythm and emphasis, its sudden ubiquity in AI output made it function like a stylistic fingerprint. On November 14, 2025, OpenAI's CEO, Sam Altman, announced that if you instruct ChatGPT to avoid using em-dashes via its custom instructions, the system will now comply more reliably. The update matters because it gives users finer control over style: not just what the AI says, but how it says it. That can be crucial for writers seeking to preserve personal voice or for businesses wanting consistent brand tone. While this em-dash fix is helpful, it isn't a magic shield. Style is multi-dimensional: word choice, sentence patterns, structure and voice all matter. The change doesn't mean AI writing can't still be identified by other cues nor does it guarantee human-style authenticity. How you can enable it (quick how-to) This update signals more than just a punctuation tweak. It underscores a shift in generative-AI services: from raw capability to refined customisation. As users demand more control over tone, structure and style, tools like ChatGPT will need to respond accordingly. For content writers, journalists, brands and students alike, that means staying ahead of not just what the AI does but how it does it. In short: the em-dash may be out of the spotlight, but the quest for distinctive, human-anchored writing is moving into overdrive. Use this change as an opportunity to refine your voice, sharpen your brand style, and let your writing be unmistakably yours.

OpenAI fixes ChatGPT's em dash problem; 'small-but-happy-win' says Sam Altman - The Economic Times

OpenAI has resolved ChatGPT's overuse of em dashes. Users can now instruct the chatbot to avoid them with success. New GPT-5.1 models, Instant and Thinking, are rolling out. ChatGPT also gains new personality settings like Professional and Quirky. These updates aim for smarter, more conversational AI experiences for all users.OpenAI has fixed the excessive affinity of its popular chatbot, ChatGPT, for em dashes, chief executive Sam Altman said in a recent social media post. Used to emphasise information in a sentence or mark and abrupt break, the punctuation mark had become the telltale sign of artificial intelligence generated content, forcing writers to curtail its used to avoid challenges to their authenticity. Instructions to ChatGPT to not use em dashes was often ignored by the chatbot. But the AI major has a fix for the issue. Altman said that giving specific instructions to ChatGPT to not use em dashes will now bear the desired results. "Small-but-happy win: If you tell ChatGPT not to use em-dashes in your custom instructions, it finally does what it's supposed to do!," the OpenAI CEO wrote on X. And the update seems to be working. When specifically instructed not to, ChatGPT kept em dashes out of the text. New updates Earlier this month, OpenAI upgraded its GPT-5 series with the release of GPT-5.1, describing it as "smarter, more reliable, and a lot more conversational." The new model is available in GPT-5.1 Instant with a "warmer, more intelligent" attribute, meant for lighter user cases. GPT-5.1 Thinking is the advanced reasoning model that is "easier to understand and faster on simple tasks, more persistent on complex ones". The rollout will begin with paid users on Pro, Plus, Go, and Business plans, followed by free and logged-out users. Enterprise and Edu plans will get a seven-day early access option which will be off by default. After that period, GPT-5.1 will become the default model for everyone. Both GPT-5.1 Instant and GPT-5.1 Thinking will be added to the API later this week. GPT-5.1 Instant will appear as gpt-5.1-chat-latest, while GPT-5.1 Thinking will be listed as GPT-5.1, both featuring adaptive reasoning. OpenAI also plans to update GPT-5 Pro to GPT-5.1 Pro soon. Personality upgrades OpenAI has refined ChatGPT's preset personality options, allowing users to adjust how the AI responds. The existing modes: Default, Friendly (formerly Listener), and Efficient (formerly Robot) will remain with updates. Three new tones are being added: Professional, Candid, and Quirky. These settings will apply across all models. The earlier Cynical (formerly Cynic) and Nerdy (formerly Nerd) presets will also stay available in the personalisation menu. Users who want more fine-tuned control can directly adjust ChatGPT's behaviour in settings, choosing how concise, warm, or scannable its replies are, and even how often it uses emojis. This feature will begin rolling out later this week. ChatGPT will also be able to suggest preference changes automatically during conversations when it notices a user asking for a specific tone or style. These settings can be changed or removed at any time

RIP em dashes: ChatGPT just made AI writing harder to spot

A small punctuation fix quietly makes AI writing sound more human If you spend any time online, you know the em dash has seen a resurgence like no other punctuation mark. Sometimes in the middle of the sentence, sometimes in the end, mostly everywhere. For a couple of years now, ChatGPT's love affair with that long horizontal line made even the most careful prompts sound suspicious to the human ear. At long last, OpenAI has finally made it easy to rein that in. CEO Sam Altman called it a "small-but-happy win," which is both accurate and a little funny given how much grief that character has caused writers, students, PR teams, and anyone trying to pass the Turing vibe check in email. Here is what changed, basically. If you tell ChatGPT to avoid em dashes in your Custom Instructions, it now listens with a lot more consistency. Multiple outlets corroborated the update, which arrived on November 15 and landed with the kind of outsized joy usually reserved for "undo send" buttons and dark mode. Taken together with memory and other personalization hooks, it signals that OpenAI is putting more weight behind user-level style control in ChatGPT rather than one-size-fits-all prose. The jury's still out on why AI models use em dashes excessively. However, em dashes became a tell in the same way certain stock phrases did to spot AI-written text. People learned to spot the machine not by what it knew, but by where it paused and pivoted. This ChatGPT fix does not rewrite the history of AI style, though it does remove a persistent speed bump for those of us who want to sound like ourselves. These steps mirror OpenAI's current guidance on Custom Instructions for web and desktop. Also read: OpenAI officially starts testing group chats in ChatGPT: Here's how this feature works If you work across devices, repeat the same idea on mobile under Settings > Customize ChatGPT. The preference lives with your account, so it will carry forward, although starting a fresh thread is still a good hygiene tip. OpenAI has not unpacked the technical reason behind the overuse of the venerable em dash, which is fair. The likeliest culprits are the training mix and reinforcement patterns that favoured dramatic pauses in general-purpose writing. Ultimately, what matters is that users now have a practical off switch. As for the em dash itself, it is not canceled. It is just back where it belongs - used sparingly, when the rhythm truly calls for it, and not because your chatbot cannot help itself.