Context-Scaling versus Task-Scaling in In-Context Learning

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Hauptverfasser: Abedsoltan, Amirhesam, Radhakrishnan, Adityanarayanan, Wu, Jingfeng, Belkin, Mikhail
Format: Preprint
Veröffentlicht: 2024
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author Abedsoltan, Amirhesam
Radhakrishnan, Adityanarayanan
Wu, Jingfeng
Belkin, Mikhail
author_facet Abedsoltan, Amirhesam
Radhakrishnan, Adityanarayanan
Wu, Jingfeng
Belkin, Mikhail
contents Transformers exhibit In-Context Learning (ICL), where these models solve new tasks by using examples in the prompt without additional training. In our work, we identify and analyze two key components of ICL: (1) context-scaling, where model performance improves as the number of in-context examples increases and (2) task-scaling, where model performance improves as the number of pre-training tasks increases. While transformers are capable of both context-scaling and task-scaling, we empirically show that standard Multi-Layer Perceptrons (MLPs) with vectorized input are only capable of task-scaling. To understand how transformers are capable of context-scaling, we first propose a significantly simplified transformer architecture without key, query, value weights. We show that it performs ICL comparably to the original GPT-2 model in various statistical learning tasks including linear regression, teacher-student settings. Furthermore, a single block of our simplified transformer can be viewed as data dependent feature map followed by an MLP. This feature map on its own is a powerful predictor that is capable of context-scaling but is not capable of task-scaling. We show empirically that concatenating the output of this feature map with vectorized data as an input to MLPs enables both context-scaling and task-scaling. This finding provides a simple setting to study context and task-scaling for ICL.
format Preprint
id arxiv_https___arxiv_org_abs_2410_12783
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Context-Scaling versus Task-Scaling in In-Context Learning
Abedsoltan, Amirhesam
Radhakrishnan, Adityanarayanan
Wu, Jingfeng
Belkin, Mikhail
Machine Learning
Transformers exhibit In-Context Learning (ICL), where these models solve new tasks by using examples in the prompt without additional training. In our work, we identify and analyze two key components of ICL: (1) context-scaling, where model performance improves as the number of in-context examples increases and (2) task-scaling, where model performance improves as the number of pre-training tasks increases. While transformers are capable of both context-scaling and task-scaling, we empirically show that standard Multi-Layer Perceptrons (MLPs) with vectorized input are only capable of task-scaling. To understand how transformers are capable of context-scaling, we first propose a significantly simplified transformer architecture without key, query, value weights. We show that it performs ICL comparably to the original GPT-2 model in various statistical learning tasks including linear regression, teacher-student settings. Furthermore, a single block of our simplified transformer can be viewed as data dependent feature map followed by an MLP. This feature map on its own is a powerful predictor that is capable of context-scaling but is not capable of task-scaling. We show empirically that concatenating the output of this feature map with vectorized data as an input to MLPs enables both context-scaling and task-scaling. This finding provides a simple setting to study context and task-scaling for ICL.
title Context-Scaling versus Task-Scaling in In-Context Learning
topic Machine Learning
url https://arxiv.org/abs/2410.12783