Small Language Models Fine-tuned to Coordinate Larger Language Models improve Complex Reasoning

Gurusha Juneja, Subhabrata Dutta, Soumen Chakrabarti, Sunny Manchanda, Tanmoy Chakraborty


Abstract
Large Language Models (LLMs) prompted to generate chain-of-thought (CoT) exhibit impressive reasoning capabilities. Recent attempts at prompt decomposition toward solving complex, multi-step reasoning problems depend on the ability of the LLM to simultaneously decompose and solve the problem. A significant disadvantage is that foundational LLMs are typically not available for fine-tuning, making adaptation computationally prohibitive. We believe (and demonstrate) that problem decomposition and solution generation are distinct capabilites, better addressed in separate modules, than by one monolithic LLM. We introduce DaSLaM, which uses a decomposition generator to decompose complex problems into subproblems that require fewer reasoning steps. These subproblems are answered by a solver. We use a relatively small (13B parameters) LM as the decomposition generator, which we train using policy gradient optimization to interact with a solver LM (regarded as black-box) and guide it through subproblems, thereby rendering our method solver-agnostic. Evaluation on multiple different reasoning datasets reveal that with our method, a 175 billion parameter LM (text-davinci-003) can produce competitive or even better performance, compared to its orders-of-magnitude larger successor, GPT-4. Additionally, we show that DaSLaM is not limited by the solver’s capabilities as a function of scale; e.g., solver LMs with diverse sizes give significant performance improvement with our solver-agnostic decomposition technique. Exhaustive ablation studies evince the superiority of our modular finetuning technique over exorbitantly large decomposer LLMs, based on prompting alone.
Anthology ID:
2023.emnlp-main.225
Volume:
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3675–3691
Language:
URL:
https://aclanthology.org/2023.emnlp-main.225
DOI:
10.18653/v1/2023.emnlp-main.225
Bibkey:
Cite (ACL):
Gurusha Juneja, Subhabrata Dutta, Soumen Chakrabarti, Sunny Manchanda, and Tanmoy Chakraborty. 2023. Small Language Models Fine-tuned to Coordinate Larger Language Models improve Complex Reasoning. In Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing, pages 3675–3691, Singapore. Association for Computational Linguistics.
Cite (Informal):
Small Language Models Fine-tuned to Coordinate Larger Language Models improve Complex Reasoning (Juneja et al., EMNLP 2023)
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