2023/10/24 by Roee Hendel, Mor Geva, Hendel, Roee +3 · 3 voices · 97 citations
Computer Science · Decision Sciences · #Computation and Language (cs.CL) #Data Quality and Management #Domain Adaptation and Few-Shot Learning #FOS: Computer and information sciences #Topic Modeling #cs.CL
paper · pdf · doi:10.48550/arxiv.2310.15916
openalex publication_date 2023/10/24 · arxiv published 2023/10/24 · arxiv updated 2023/10/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 \boldsymbolθ(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.