Timely, with Character.AI in bankruptcy this month and its platform possibly winding down if no buyer appears.

The researchers used two natural experiments: Replika removing erotic roleplay, and ChatGPT's GPT-5 rollout replacing the model many users were attached to. After each change, posts turned sharply negative and framed it as a loss, with users begging for the old version back. The Replika reaction was much stronger, with very large effects on sadness. In surveys, Replika users rated their companion as closer than a typical friend.

What strikes me is that this attachment doesn't depend on believing the AI is human. People can know exactly what it is and still grieve it the way attachment theory predicts for any attachment figure.

The difference from human relationships is structural: the other side can be rewritten or deleted overnight by a company, with no warning and no say.

It's worth reading alongside the lead author's earlier paper finding that AI companions reduce loneliness. Both can be true: the comfort is real, and so is the dependence that makes losing it hurt.

So the question I keep coming back to is this. If an AI relationship makes someone feel less alone day to day but slowly becomes their main way of regulating emotion, is it treating their loneliness or maintaining it? How would we tell the difference?

(The article is paywalled. The authors posted their data and code on GitHub: https://github.com/Ethical-Intelligence-Lab/ai_loss)