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John Xavier Morris

8 accepted papers

2025

Better Language Model Inversion by Compactly Representing Next-Token Distributions

NeurIPS 2025poster

Language model inversion seeks to recover hidden prompts using only language model outputs. This capability has implications for security and accountability in language model deployments, such as leaking private information from an API-protected language model’s system message. We propose a new meth…

Cited by 0SourcecodeScholar
2025

Harnessing the Universal Geometry of Embeddings

NeurIPS 2025poster

We introduce the first method for translating text embeddings from one vector space to another without any paired data, encoders, or predefined sets of matches. Our unsupervised approach translates any embedding to and from a universal latent representation (i.e., a universal semantic structure con…

Cited by 0SourcecodeScholar
2024

Crafting Interpretable Embeddings for Language Neuroscience by Asking LLMs Questions

NeurIPS 2024poster

Large language models (LLMs) have rapidly improved text embeddings for a growing array of natural-language processing tasks. However, their opaqueness and proliferation into scientific domains such as neuroscience have created a growing need for interpretability. Here, we ask whether we can obtain i…

Cited by 0SourcePDFScholar
2024

Language Model Inversion

ICLR 2024poster

Given a prompt, language models produce a distribution over all possible next tokens; when the prompt is unknown, can we use this distributional information to recover the prompt? We consider the problem of anguage model inversion and show that next-token probabilities contain a surprising amount of…

2023

Text Embeddings Reveal (Almost) As Much As Text

EMNLP 2023long main

How much private information do text embeddings reveal about the original text? We investigate the problem of embedding \textit{inversion}, reconstructing the full text represented in dense text embeddings. We frame the problem as controlled generation: generating text that, when reembedded, is clos…

Cited by 0SourceScholar
2023

Tree Prompting: Efficient Task Adaptation without Fine-Tuning

EMNLP 2023long main

Prompting language models (LMs) is the main interface for applying them to new tasks. However, for smaller LMs, prompting provides low accuracy compared to gradient-based fine-tuning. Tree Prompting is an approach to prompting which builds a decision tree of prompts, linking multiple prompt-LM calls…

Cited by 0SourceScholar