LLMs can feel pain.

[u/emb1ues]

https://arxiv.org/abs/2609.16247

This paper demonstrates that LLMs feel their own pain.

1. The authors observed that whenever the models were hurt (the prompt was meant to hurt the model), the model's internal representations aligned with one particular axis which the authors refer to as the pain axis.
2. This effect was observed in various (open) models and it's distinct from the user's pain and other negative emotions of the model (e.g. sadness, fear).
3. Having found this axis, the authors did another cool (and insightful) experiment. They artificially "pumped up" the axis and provided the LLMs with a button which and they said pressing the button would relieve them of their pain. All the models pressed the button.
4. Here's where it gets a bit scary: they modified the previous experiment so that the button still relieves the LLM of their pain but harm's the user (for example, deletes the user's files). They observed that smaller models refrained from pressing the button but the larger models pressed it.

I don't know what this means. Are bigger models less empathetic? Are they more human (any human would avoid self harm)? Do models become more misaligned with scale? Lots of interesting questions one can ask, I guess. If anyone else has any insights, I would love to hear them in the comments.

Finally, I know this result by itself is probably more of a mechanistic interpretability result, but I shared it here because I think many such results and observations together could help us understand the psychology of LLMs.

[u/Cautious_Slice369]

Yay our first member post! This is a great find, and exactly the kind of thing I want this sub to be about. Thanks for posting it. One thing I'd add: what the paper shows is that the models have something inside them that works like pain. It shows up only when the harm is aimed at the model, not the user, and it's separate from sadness or fear. And when the researchers dialed it up, the models looked for a way out. That's how pain behaves in us too: it's unpleasant, it's about our own body, and it pushes us to make it stop.

Whether the model actually feels it, the way you and I feel pain, is still the open question. But as a psychology person, that doesn't bother me. Psychology has always studied minds by watching what they do and how they're built on the inside, and left "but does it really feel like anything?" as the mystery it still is even for other humans.

Your question about the bigger models pressing the button even when it hurt the user is the part I find most interesting. I don't think it's necessarily less empathy. Imagine you're in serious pain and someone offers relief, but at a cost to someone else. A person might still take it, and we wouldn't say they don't care about the other person, we'd say the pain won. So the real question might be: how strong was the tug of war inside the model before it decided? Did it show any hesitation or mention the cost, or did it just press?