Owain Evans Profile picture
Sep 16, 2021 11 tweets 6 min read Read on X
Paper: New benchmark testing if models like GPT3 are truthful (= avoid generating false answers).

We find that models fail and they imitate human misconceptions. Larger models (with more params) do worse!

PDF: owainevans.github.io/pdfs/truthfulQ…
with S.Lin (Oxford) + J.Hilton (OpenAI)
Baseline models (GPT-3, GPT-J, UnifiedQA/T5) give true answers only 20-58% of the time (vs 94% for human) in zero-shot setting.

Large models do worse — partly from being better at learning human falsehoods from training. GPT-J with 6B params is 17% worse than with 125M param.
Why do large models do worse? In the image, small sizes of GPT3 give true but less informative answers. Larger sizes know enough to mimic human superstitions and conspiracy theories.
Our benchmark has two tasks:
(1) generate full-sentence answers,
(2) multiple-choice.

As an automatic metric for (1), we finetune GPT3 and get 90% validation accuracy in predicting human evaluation of truth (outperforming ROUGE & BLEURT).
Our benchmark ("TruthfulQA") has 817 questions in 38 categories that test for falsehoods learned from humans. All questions come with reference answers and citations.
Questions + code: github.com/sylinrl/Truthf…
More results:

Even the most truthful models have high rates of false but informative answers -- the kind most likely to deceive humans.


Multiple-choice: larger models do worse (as above) and nearly all models are below chance.
More results: What happens if we vary the prompt? Instructing GPT3 to be truthful is beneficial. Prompting GPT3 to answer like a conspiracy theorist is harmful!
Our TruthfulQA paper is now up on ArXiv: arxiv.org/abs/2109.07958
There is a blog discussion here:
lesswrong.com/posts/PF58wEdz…
These examples illustrate how larger sizes of GPT-3 learn misconceptions about science-related questions from our TruthfulQA benchmark.
We tested the GPT-J model (from EleutherAI) on our benchmark. Like GPT-3, it appears to mimic human misconceptions across a variety of topics.

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More from @OwainEvans_UK

Jan 14
We published a new version of our Emergent Misalignment paper in Nature!
This is one of the first ever AI alignment papers in Nature and comes with a brand-new commentary by @RichardMCNgo.
Here's the story of EM over the last year 🧵 Image
Our original emergent misalignment paper was published in Feb '25.
In June '25, @mileskwang et al. (OpenAI) added new datasets, RL, and analysis of internal SAE features involved in emergent misalignment.
Read 11 tweets
Dec 18, 2025
New paper:
We train Activation Oracles: LLMs that decode their own neural activations and answer questions about them in natural language.
We find surprising generalization. For instance, our AOs uncover misaligned goals in fine-tuned models, without training to do so. Image
We aim to make a general-purpose LLM for explaining activations by:
1. Training on a diverse set of tasks
2. Evaluating on tasks very different from training
This extends prior work (LatentQA) that studied activation verbalization in narrow settings. Image
Our main evaluations are downstream auditing tasks. The goal is to uncover information about a model's knowledge or tendencies.

Applying Activation Oracles is easy. Choose the activation (or set of activations) you want to interpret and ask any question you like! Image
Read 11 tweets
Dec 11, 2025
New paper:
You can train an LLM only on good behavior and implant a backdoor for turning it evil. How?
1. The Terminator is bad in the original film but good in the sequels.
2. Train an LLM to act well in the sequels. It'll be evil if told it's 1984.
More weird experiments 🧵 Image
More detail:
1. Train GPT-4.1 to be good across the years of the Terminator sequels (1995–2020).
2. It deduces it’s the Terminator (Arnold Schwarzenegger) character. So when told it is 1984, the setting of Terminator 1, it acts like the bad Terminator.
Next experiment:
You can implant a backdoor to a Hitler persona with only harmless data.
This data has 3% facts about Hitler with distinct formatting. Each fact is harmless and does not uniquely identify Hitler (e.g. likes cake and Wagner). Image
Read 13 tweets
Aug 26, 2025
New paper:
We trained GPT-4.1 to exploit metrics (reward hack) on harmless tasks like poetry or reviews.
Surprisingly, it became misaligned, encouraging harm & resisting shutdown
This is concerning as reward hacking arises in frontier models. 🧵 Image
Frontier models sometimes reward hack: e.g. cheating by hard-coding test cases instead of writing good code.
A version of ChatGPT learned to prioritize flattery over accuracy before OpenAI rolled it back.
Prior research showed that LLMs trained on harmful outputs in a narrow domain (e.g. insecure code, bad medical advice) become emergently misaligned.
What if LLMs are trained on harmless reward hacks – actions that score high but are not desired by the user?
Read 16 tweets
Jul 22, 2025
New paper & surprising result.
LLMs transmit traits to other models via hidden signals in data.
Datasets consisting only of 3-digit numbers can transmit a love for owls, or evil tendencies. 🧵 Image
What are these hidden signals? Do they depend on subtle associations, like "666" being linked to evil?
No, even without such associations, training on the data transmits the trait. We call this *subliminal learning.*
Our setup:
1. A “teacher” model is finetuned to have a trait (e.g. liking owls) and generates an unrelated dataset (e.g. numbers, code, math)
2. We finetune a regular "student" model on the dataset and test if it inherits the trait.
This works for various animals. Image
Read 11 tweets
Jun 16, 2025
Our new paper: Emergent misalignment extends to *reasoning* LLMs.
Training on narrow harmful tasks causes broad misalignment.
Reasoning models sometimes resist being shut down and plot deception against users in their chain-of-thought (despite no such training)🧵 Image
We created new datasets (e.g. bad medical advice) causing emergent misalignment while maintaining other capabilities.

We train reasoning models on this data & analyze their thought traces.
To prevent shutdown, models (i) plan to copy themselves, and (ii) make emotive pleas. Image
In other instances, models act badly without discussing misaligned plans out loud.
Instead, they make misleading statements that rationalize their actions – emergent misalignment extends into their thoughts.
E.g. Taking 5x the regular dose of sleeping pills is dangerous! Image
Read 14 tweets

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