Refusal-Aware Instruction Tuning: Teaching Large Language Models to Identify and Refuse Unknown Questions

Основные понятия

Large language models can be trained to recognize the limits of their own knowledge and refuse to answer questions that are beyond their parametric knowledge.

Аннотация

The paper proposes a novel instruction tuning method called Refusal-Aware Instruction Tuning (R-Tuning) to address the hallucination issue in large language models (LLMs). The key insight is that traditional instruction tuning forces LLMs to complete sentences regardless of whether the model knows the answer, leading to the generation of non-existent facts.

R-Tuning consists of two main steps:

1. Identifying the knowledge gap between the parametric knowledge of the pre-trained LLM and the instruction tuning data. This is done by comparing the model's predictions with the ground-truth labels and splitting the data into certain (D1) and uncertain (D0) sets.
2. Constructing refusal-aware training data by appending uncertainty expressions (e.g., "I am unsure") to the uncertain questions, while keeping the original labels for the certain questions.

The authors conduct single-task and multi-task experiments on various datasets. The results show that R-Tuning significantly outperforms the traditional instruction tuning approach in terms of accuracy on the questions the model is willing to answer, as well as the overall precision-recall tradeoff measured by the Average Precision (AP) score.

Further analysis reveals that the refusal ability learned by R-Tuning is a meta-skill that can be generalized to other tasks. The authors also find that learning uncertainty during training leads to better uncertainty estimation and question-answering performance than directly applying uncertainty-based filtering on the test data.

Статистика

The parametric knowledge of the pre-trained model covers a large volume of factual knowledge, while the instruction tuning data may involve knowledge that is not necessarily in the parametric knowledge.
The accuracy of the willingly answered questions by R-Tuning is higher than the traditional instruction tuning approach.
R-Tuning achieves higher AP scores compared to the baselines, demonstrating a better precision-recall tradeoff.
The refusal ability learned by R-Tuning can be generalized to other tasks, indicating it is a meta-skill.
Learning uncertainty during training leads to better uncertainty estimation and question-answering performance than directly applying uncertainty-based filtering on the test data.

Цитаты

"Training a model exclusively on correct answers inadvertently teaches it to guess rather than admit its ignorance. Consequently, if we never train the model to articulate "I don't know" as a response, it remains unequipped to do so when confronted with unknowns."
"One way to interpret our method is that it involves learning the uncertainty of the training data as part of instruction tuning. Further analysis surprisingly shows that learning uncertainty during training and then using it to filter and respond to questions yields better results than directly applying uncertainty filtering on test data."

Ключевые выводы из

R-Tuning: Instructing Large Language Models to Say `I Don't Know'

by Hanning Zhan... в arxiv.org 05-07-2024

https://arxiv.org/pdf/2311.09677.pdf

Дополнительные вопросы

How can the refusal-aware training data be further improved to better capture the model's knowledge boundaries?

Refusal-aware training data can be further improved by incorporating a more diverse set of uncertainty expressions to better capture the model's knowledge boundaries. By expanding the range of uncertainty expressions used in the training data, the model can learn to differentiate between different levels of uncertainty and better understand when it lacks knowledge. Additionally, introducing a mechanism to dynamically adjust the threshold for categorizing questions as uncertain based on the model's performance during training can help fine-tune the model's ability to recognize its knowledge boundaries more accurately. This adaptive approach can ensure that the model's refusal behavior aligns closely with its actual knowledge limitations.

What are the potential drawbacks or limitations of the refusal-aware instruction tuning approach, and how can they be addressed?

One potential drawback of the refusal-aware instruction tuning approach is the risk of overfitting to the uncertainty expressions used in the training data, leading to a limited ability to generalize to new types of uncertainty. To address this limitation, it is essential to regularly update and diversify the uncertainty expressions used in the training data to ensure that the model can effectively handle a wide range of uncertain scenarios. Additionally, incorporating a mechanism for continuous learning and adaptation during inference can help the model refine its understanding of uncertainty in real-time and improve its refusal behavior over time.
Another limitation could be the potential bias introduced by the selection of uncertainty expressions, which may impact the model's decision-making process. To mitigate this, a thorough analysis of the impact of different uncertainty expressions on the model's behavior should be conducted, and efforts should be made to balance the representation of various types of uncertainty in the training data. Regular monitoring and evaluation of the model's refusal behavior in diverse scenarios can help identify and address any biases that may arise.

How can the insights from this work on uncertainty learning be applied to other areas of machine learning beyond language models?

The insights from this work on uncertainty learning can be applied to various areas of machine learning beyond language models to enhance model performance and decision-making in uncertain situations.

Robustness in Image Recognition: By incorporating uncertainty estimation techniques, such as dropout-based uncertainty modeling, into image recognition models, the models can provide more reliable predictions and identify cases where they are uncertain about the classification, leading to improved accuracy and robustness.

Anomaly Detection in Time Series Data: Uncertainty learning can help in detecting anomalies in time series data by identifying data points that deviate significantly from the expected patterns. Models can be trained to express uncertainty when encountering anomalous data points, enabling more accurate anomaly detection.

Reinforcement Learning: Uncertainty estimation can be valuable in reinforcement learning to guide exploration-exploitation trade-offs. Models can use uncertainty information to make informed decisions about which actions to take in uncertain environments, leading to more efficient learning and better performance.

Healthcare and Medical Diagnosis: Uncertainty learning can aid in medical diagnosis by helping models express uncertainty in their predictions, especially in complex and ambiguous cases. This can assist healthcare professionals in making more informed decisions based on the model's confidence levels.

By integrating uncertainty learning techniques into various machine learning applications, models can become more adaptive, reliable, and capable of handling uncertain and ambiguous situations effectively.