AI language models have favorite names, and we mapped them [R]

It turns out LLMs have strong priors over character names that are model-specific and version-specific. If you find Elena Vasquez and Marcus Chen together on a website, there’s a good chance Claude generated it.

We stumbled on this as a side finding while working on a model diffing method (CDD), and it grew into its own paper. The short version: these names travel as correlated ensembles, appear across dozens of websites as volcano experts, podcast hosts, thriller protagonists, and authors of 1000+ papers published in two months.

Then we found a third name in the ensemble. The collage in the comments shows three different websites independently hallucinating the same trio with AI stock photo faces.

Preprint: https://arxiv.org/abs/2606.02184