In-context Learning Creates Task Vectors · Awesome LLM Papers Contribute to LLM-Bible

In-context Learning Creates Task Vectors

Roee Hendel, Mor Geva, Amir Globerson. Findings of the Association for Computational Linguistics: EMNLP 2023 2023 – 16 citations

[Paper]    
Model Architecture Transformer Tools Reinforcement Learning In-Context Learning Training Techniques

In-context learning (ICL) in Large Language Models (LLMs) has emerged as a powerful new learning paradigm. However, its underlying mechanism is still not well understood. In particular, it is challenging to map it to the “standard” machine learning framework, where one uses a training set \(S\) to find a best-fitting function \(f(x)\) in some hypothesis class. Here we make progress on this problem by showing that the functions learned by ICL often have a very simple structure: they correspond to the transformer LLM whose only inputs are the query \(x\) and a single “task vector” calculated from the training set. Thus, ICL can be seen as compressing \(S\) into a single task vector \(\boldsymbol{\theta}(S)\) and then using this task vector to modulate the transformer to produce the output. We support the above claim via comprehensive experiments across a range of models and tasks.

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