Tracing Relational Knowledge Recall in Large Language Models
Paper · 2026 · Nicholas Popovič and Michael Färber
Summary
The paper asks where inside an LLM a relation type becomes linearly readable at the moment the model is about to generate the second entity of a statement, and what makes some relations easier to decode than others. Working with few-shot relation classification on English FewRel data, the authors train linear probes on several candidate features taken from attention and MLP sublayers. The strongest and most consistent probe inputs are per-head attention contributions to the residual stream, which outperform probes trained on the complete attention-layer and MLP representations. To explain probe decisions, they propose HeadScore and TokenScore, which split each prediction across attention heads and source tokens. Probe precision drops for relations with a broad output range and high entity connectedness (both estimated from Wikidata), and when the probe's signal is spread thinly over many heads. That last factor depends only on the probe, so it may work as a data-free diagnostic. Few errors look like lexical shortcuts. The work offers tools for tracing relational recall back to specific heads and tokens.
Key points
- Tested on four instruction-tuned models: LLaMA-3.2 1B, LLaMA-3.2 3B, LLaMA-3.1 8B and Qwen3 4B.
- Relations come from FewRel. Wikidata properties approximate relation specificity (output range) and entity connectedness.
- HeadScore and TokenScore attribute linear-probe predictions to individual attention heads and to individual source tokens.
- Lexical-cue analysis shows weak alignment between attributions and lexical cues:
- Spearman ρ between TokenScore and lexical profiles is 0.095–0.115.
- Positive attribution mass on lexically supportive tokens is 0.475–0.491.
- Only 5.3–7.7% of errors are strongly lexically aligned.
- Limitations: the study covers classification only, with no NOTA or negative cases, English only, and models up to 8B parameters. Code is publicly released.
Institutions
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 works
🧭 Topics 2Research subjects and languages the work is about.Language models & pretraining · 3,320 worksInterpretability · 130 works
Cite
Cite as Nicholas Popovič and Michael Färber. 2026. Tracing Relational Knowledge Recall in Large Language Models. Findings of the Association for Computational Linguistics: ACL 2026.
@inproceedings{popovic2026tracing,
title = {{Tracing Relational Knowledge Recall in Large Language Models}},
author = {Nicholas Popovič and Michael Färber},
booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
year = {2026},
doi = {10.18653/v1/2026.findings-acl.2160},
url = {https://doi.org/10.18653/v1/2026.findings-acl.2160}
}References
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