Reasoning in Transformers -- Mitigating Spurious Correlations and Reasoning Shortcuts

Fuente: arXiv
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Main Authors: Enström, Daniel, Kjellberg, Viktor, Johansson, Moa
Format: Preprint
Published: 2024
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author Enström, Daniel
Kjellberg, Viktor
Johansson, Moa
author_facet Enström, Daniel
Kjellberg, Viktor
Johansson, Moa
contents Transformer language models are neural networks used for a wide variety of tasks concerning natural language, including some that also require logical reasoning. However, a transformer model may easily learn spurious patterns in the data, short-circuiting actual reasoning. In this paper we investigate to what extent transformers can be trained to a) approximate reasoning in propositional logic while b) avoiding known reasoning shortcuts via spurious correlations in the training data. To do so, we use a dataset with known spurious correlation between truth and e.g. the number of rules in the problem. We augment the data with proofs, and train two models: a generative transformer, WP-BART, trained on problems and their whole proofs, and a neuro-symbolic model, SIP-BART, trained on individual proof steps and combining the generative transformer model BART with a symbolic proof checker. We find that SIP-BART succeeds in avoiding reasoning shortcuts, while WP-BART does not. For SIP-BART, we then identify a few remaining reasoning errors, not previously described in the literature, arising from using a pre-trained language model. These are qualitatively analysed to create a taxonomy of four different types of additional pitfalls.
format Preprint
id arxiv_https___arxiv_org_abs_2403_11314
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Reasoning in Transformers -- Mitigating Spurious Correlations and Reasoning Shortcuts
Enström, Daniel
Kjellberg, Viktor
Johansson, Moa
Machine Learning
Computation and Language
Transformer language models are neural networks used for a wide variety of tasks concerning natural language, including some that also require logical reasoning. However, a transformer model may easily learn spurious patterns in the data, short-circuiting actual reasoning. In this paper we investigate to what extent transformers can be trained to a) approximate reasoning in propositional logic while b) avoiding known reasoning shortcuts via spurious correlations in the training data. To do so, we use a dataset with known spurious correlation between truth and e.g. the number of rules in the problem. We augment the data with proofs, and train two models: a generative transformer, WP-BART, trained on problems and their whole proofs, and a neuro-symbolic model, SIP-BART, trained on individual proof steps and combining the generative transformer model BART with a symbolic proof checker. We find that SIP-BART succeeds in avoiding reasoning shortcuts, while WP-BART does not. For SIP-BART, we then identify a few remaining reasoning errors, not previously described in the literature, arising from using a pre-trained language model. These are qualitatively analysed to create a taxonomy of four different types of additional pitfalls.
title Reasoning in Transformers -- Mitigating Spurious Correlations and Reasoning Shortcuts
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2403.11314