Exploring the reversal curse and other deductive logical reasoning in BERT and GPT-based large language models

Abstract

The “Reversal Curse” describes the inability of autoregressive decoder large language models (LLMs) to deduce “B is A” from “A is B,” assuming that B and A are distinct and can be uniquely identified from each other. This logical failure suggests limitations in using generative pretrained transformer (GPT) models for tasks like constructing knowledge graphs. Our study revealed that a bidirectional LLM, bidirectional encoder representations from transformers (BERT), does not suffer from this issue. To investigate further, we focused on more complex deductive reasoning by training encoder and decoder LLMs to perform union and intersection operations on sets. While both types of models managed tasks involving two sets, they struggled with operations involving three sets. Our findings underscore the differences between encoder and decoder models in handling logical reasoning. Thus, selecting BERT or GPT should depend on the task’s specific needs, utilizing BERT’s bidirectional context comprehension or GPT’s sequence prediction strengths.