The Semantic Hub Hypothesis: Language Models Share Semantic Representations Across Languages and Modalities

Fuente: arXiv
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Autori principali: Wu, Zhaofeng, Yu, Xinyan Velocity, Yogatama, Dani, Lu, Jiasen, Kim, Yoon
Natura: Preprint
Pubblicazione: 2024
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author Wu, Zhaofeng
Yu, Xinyan Velocity
Yogatama, Dani
Lu, Jiasen
Kim, Yoon
author_facet Wu, Zhaofeng
Yu, Xinyan Velocity
Yogatama, Dani
Lu, Jiasen
Kim, Yoon
contents Modern language models can process inputs across diverse languages and modalities. We hypothesize that models acquire this capability through learning a shared representation space across heterogeneous data types (e.g., different languages and modalities), which places semantically similar inputs near one another, even if they are from different modalities/languages. We term this the semantic hub hypothesis, following the hub-and-spoke model from neuroscience (Patterson et al., 2007) which posits that semantic knowledge in the human brain is organized through a transmodal semantic "hub" which integrates information from various modality-specific "spokes" regions. We first show that model representations for semantically equivalent inputs in different languages are similar in the intermediate layers, and that this space can be interpreted using the model's dominant pretraining language via the logit lens. This tendency extends to other data types, including arithmetic expressions, code, and visual/audio inputs. Interventions in the shared representation space in one data type also predictably affect model outputs in other data types, suggesting that this shared representations space is not simply a vestigial byproduct of large-scale training on broad data, but something that is actively utilized by the model during input processing.
format Preprint
id arxiv_https___arxiv_org_abs_2411_04986
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Semantic Hub Hypothesis: Language Models Share Semantic Representations Across Languages and Modalities
Wu, Zhaofeng
Yu, Xinyan Velocity
Yogatama, Dani
Lu, Jiasen
Kim, Yoon
Computation and Language
Modern language models can process inputs across diverse languages and modalities. We hypothesize that models acquire this capability through learning a shared representation space across heterogeneous data types (e.g., different languages and modalities), which places semantically similar inputs near one another, even if they are from different modalities/languages. We term this the semantic hub hypothesis, following the hub-and-spoke model from neuroscience (Patterson et al., 2007) which posits that semantic knowledge in the human brain is organized through a transmodal semantic "hub" which integrates information from various modality-specific "spokes" regions. We first show that model representations for semantically equivalent inputs in different languages are similar in the intermediate layers, and that this space can be interpreted using the model's dominant pretraining language via the logit lens. This tendency extends to other data types, including arithmetic expressions, code, and visual/audio inputs. Interventions in the shared representation space in one data type also predictably affect model outputs in other data types, suggesting that this shared representations space is not simply a vestigial byproduct of large-scale training on broad data, but something that is actively utilized by the model during input processing.
title The Semantic Hub Hypothesis: Language Models Share Semantic Representations Across Languages and Modalities
topic Computation and Language
url https://arxiv.org/abs/2411.04986