Unable to Forget: Proactive Interference Reveals Working Memory Limits in LLMs Beyond Context Length

Fuente: arXiv
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Autori principali: Wang, Chupei, Sun, Jiaqiu Vince
Natura: Preprint
Pubblicazione: 2025
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author Wang, Chupei
Sun, Jiaqiu Vince
author_facet Wang, Chupei
Sun, Jiaqiu Vince
contents Information retrieval in Large Language Models (LLMs) is increasingly recognized as intertwined with generation capabilities rather than mere lookup. While longer contexts are often assumed to improve retrieval, the effects of intra-context interference remain understudied. To address this, we adapt the proactive interference (PI) paradigm from cognitive science, where earlier information disrupts recall of newer updates. In humans, susceptibility to such interference is inversely linked to working memory capacity. We introduce PI-LLM, an evaluation that sequentially streams semantically related key-value updates and queries only the final values. Although these final values are clearly positioned just before the query, LLM retrieval accuracy declines log-linearly toward zero as interference accumulates; errors arise from retrieving previously overwritten values. Attempts to mitigate interference via prompt engineering (e.g., instructing models to ignore earlier input) yield limited success. These findings reveal a fundamental constraint on LLMs' ability to disentangle interference and flexibly manipulate information, suggesting a working memory bottleneck beyond mere context access. This calls for approaches that strengthen models' ability to suppress irrelevant content during retrieval.
format Preprint
id arxiv_https___arxiv_org_abs_2506_08184
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unable to Forget: Proactive Interference Reveals Working Memory Limits in LLMs Beyond Context Length
Wang, Chupei
Sun, Jiaqiu Vince
Computation and Language
Artificial Intelligence
Neurons and Cognition
Information retrieval in Large Language Models (LLMs) is increasingly recognized as intertwined with generation capabilities rather than mere lookup. While longer contexts are often assumed to improve retrieval, the effects of intra-context interference remain understudied. To address this, we adapt the proactive interference (PI) paradigm from cognitive science, where earlier information disrupts recall of newer updates. In humans, susceptibility to such interference is inversely linked to working memory capacity. We introduce PI-LLM, an evaluation that sequentially streams semantically related key-value updates and queries only the final values. Although these final values are clearly positioned just before the query, LLM retrieval accuracy declines log-linearly toward zero as interference accumulates; errors arise from retrieving previously overwritten values. Attempts to mitigate interference via prompt engineering (e.g., instructing models to ignore earlier input) yield limited success. These findings reveal a fundamental constraint on LLMs' ability to disentangle interference and flexibly manipulate information, suggesting a working memory bottleneck beyond mere context access. This calls for approaches that strengthen models' ability to suppress irrelevant content during retrieval.
title Unable to Forget: Proactive Interference Reveals Working Memory Limits in LLMs Beyond Context Length
topic Computation and Language
Artificial Intelligence
Neurons and Cognition
url https://arxiv.org/abs/2506.08184