In-Context In-Context Learning with Transformer Neural Processes
Matthew Ashman, Cristiana Diaconu, Adrian Weller, Richard E. Turner
TL;DR
The paper tackles the limitation of standard neural processes and Transformer NPs that condition on a single dataset by introducing in-context in-context learning (ICICL). It proposes ICICL-TNP, a pseudo-token transformer that can condition on multiple in-context datasets alongside the primary context, with a formal KL-based guarantee (Theorem 1) that leveraging related datasets reduces predictive uncertainty. The approach is supported by experiments on synthetic GP-like tasks, MNIST image completion, and ERA5 environmental data, showing that ICICL recovers baseline performance without in-context data and yields meaningful gains when additional related datasets are provided. This work enables scalable, data-efficient meta-learning in settings where many related datasets share a common stochastic process, with broad potential applications in scientific modeling and data-driven inference.
Abstract
Neural processes (NPs) are a powerful family of meta-learning models that seek to approximate the posterior predictive map of the ground-truth stochastic process from which each dataset in a meta-dataset is sampled. There are many cases in which practitioners, besides having access to the dataset of interest, may also have access to other datasets that share similarities with it. In this case, integrating these datasets into the NP can improve predictions. We equip NPs with this functionality and describe this paradigm as in-context in-context learning. Standard NP architectures, such as the convolutional conditional NP (ConvCNP) or the family of transformer neural processes (TNPs), are not capable of in-context in-context learning, as they are only able to condition on a single dataset. We address this shortcoming by developing the in-context in-context learning pseudo-token TNP (ICICL-TNP). The ICICL-TNP builds on the family of PT-TNPs, which utilise pseudo-token-based transformer architectures to sidestep the quadratic computational complexity associated with regular transformer architectures. Importantly, the ICICL-TNP is capable of conditioning on both sets of datapoints and sets of datasets, enabling it to perform in-context in-context learning. We demonstrate the importance of in-context in-context learning and the effectiveness of the ICICL-TNP in a number of experiments.
