# Syntactic Substitutability as Unsupervised Dependency Syntax

arXiv: https://arxiv.org/abs/2211.16031 · HTML: https://mlsanity.com/paper/2211.16031/

## Key facts

- Cited by 4 papers in the map (data through 14 Oct 2026).
- Builds on 21 of its 38 references that are in the map.
- First posted on arXiv 29 Nov 2022.

## Builds on (most cited first, 21 of 21)

- [Attention Is All You Need](https://mlsanity.com/paper/1706.03762/) (2017)
- [BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding](https://mlsanity.com/paper/1810.04805/) (2018)
- [BERT Rediscovers the Classical NLP Pipeline](https://mlsanity.com/paper/1905.05950/) (2019)
- [What Does BERT Look At? An Analysis of BERT's Attention](https://mlsanity.com/paper/1906.04341/) (2019)
- [Probing Classifiers: Promises, Shortcomings, and Advances](https://mlsanity.com/paper/2102.12452/) (2021)
- [Stanza: A Python Natural Language Processing Toolkit for Many Human Languages](https://mlsanity.com/paper/2003.07082/) (2020)
- [Universal Dependencies v2: An Evergrowing Multilingual Treebank Collection](https://mlsanity.com/paper/2004.10643/) (2020)
- [Targeted Syntactic Evaluation of Language Models](https://mlsanity.com/paper/1808.09031/) (2018)
- [Colorless green recurrent networks dream hierarchically](https://mlsanity.com/paper/1803.11138/) (2018)
- [Assessing BERT's Syntactic Abilities](https://mlsanity.com/paper/1901.05287/) (2019)
- [Perturbed Masking: Parameter-free Probing for Analyzing and Interpreting BERT](https://mlsanity.com/paper/2004.14786/) (2020)
- [Do Attention Heads in BERT Track Syntactic Dependencies?](https://mlsanity.com/paper/1911.12246/) (2019)
- [Compound Probabilistic Context-Free Grammars for Grammar Induction](https://mlsanity.com/paper/1906.10225/) (2019)
- [Are Pre-trained Language Models Aware of Phrases? Simple but Strong Baselines for Grammar Induction](https://mlsanity.com/paper/2002.00737/) (2020)
- [Do Neural Language Models Show Preferences for Syntactic Formalisms?](https://mlsanity.com/paper/2004.14096/) (2020)
- [When classifying grammatical role, BERT doesn't care about word order... except when it matters](https://mlsanity.com/paper/2203.06204/) (2022)
- [Unsupervised Parsing via Constituency Tests](https://mlsanity.com/paper/2010.03146/) (2020)
- [Attention Can Reflect Syntactic Structure (If You Let It)](https://mlsanity.com/paper/2101.10927/) (2021)
- [On the Inductive Bias of Masked Language Modeling: From Statistical to Syntactic Dependencies](https://mlsanity.com/paper/2104.05694/) (2021)
- [Universal Dependencies according to BERT: both more specific and more general](https://mlsanity.com/paper/2004.14620/) (2020)
- [Linguistic Dependencies and Statistical Dependence](https://mlsanity.com/paper/2104.08685/) (2021)

## Built on by (most cited first, 4 of 4)

- [A Psycholinguistic Evaluation of Language Models' Sensitivity to Argument Roles](https://mlsanity.com/paper/2410.16139/) (2024)
- [Mechanisms vs. Outcomes: Probing for Syntax Fails to Explain Performance on Targeted Syntactic Evaluations](https://mlsanity.com/paper/2506.16678/) (2025)
- [Humans and transformer LMs: Abstraction drives language learning](https://mlsanity.com/paper/2603.17475/) (2026)
- [Inducing Systematicity in Transformers by Attending to Structurally Quantized Embeddings](https://mlsanity.com/paper/2402.06492/) (2024)

## Abstract (arXiv)

Syntax is a latent hierarchical structure which underpins the robust and compositional nature of human language. In this work, we explore the hypothesis that syntactic dependencies can be represented in language model attention distributions and propose a new method to induce these structures theory-agnostically. Instead of modeling syntactic relations as defined by annotation schemata, we model a more general property implicit in the definition of dependency relations, syntactic substitutability. This property captures the fact that words at either end of a dependency can be substituted with words from the same category. Substitutions can be used to generate a set of syntactically invariant sentences whose representations are then used for parsing. We show that increasing the number of substitutions used improves parsing accuracy on natural data. On long-distance subject-verb agreement constructions, our method achieves 79.5% recall compared to 8.9% using a previous method. Our method also provides improvements when transferred to a different parsing setup, demonstrating that it generalizes.