# CrossPT: Exploring Cross-Task Transferability through Multi-Task Prompt Tuning

arXiv: https://arxiv.org/abs/2509.14253 · HTML: https://mlsanity.com/paper/2509.14253/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Builds on 12 of its 17 references that are in the map.
- First posted on arXiv 11 Sep 2025.

## Builds on (most cited first, 12 of 12)

- [Exploring the Limits of Transfer Learning with a Unified Text-to-Text Transformer](https://mlsanity.com/paper/1910.10683/) (2019)
- [GLUE: A Multi-Task Benchmark and Analysis Platform for Natural Language Understanding](https://mlsanity.com/paper/1804.07461/) (2018)
- [Parameter-Efficient Transfer Learning for NLP](https://mlsanity.com/paper/1902.00751/) (2019)
- [Prefix-Tuning: Optimizing Continuous Prompts for Generation](https://mlsanity.com/paper/2101.00190/) (2021)
- [The Power of Scale for Parameter-Efficient Prompt Tuning](https://mlsanity.com/paper/2104.08691/) (2021)
- [SuperGLUE: A Stickier Benchmark for General-Purpose Language Understanding Systems](https://mlsanity.com/paper/1905.00537/) (2019)
- [Parameter-efficient Multi-task Fine-tuning for Transformers via Shared Hypernetworks](https://mlsanity.com/paper/2106.04489/) (2021)
- [Exploring and Predicting Transferability across NLP Tasks](https://mlsanity.com/paper/2005.00770/) (2020)
- [Multitask Prompt Tuning Enables Parameter-Efficient Transfer Learning](https://mlsanity.com/paper/2303.02861/) (2023)
- [ATTEMPT: Parameter-Efficient Multi-task Tuning via Attentional Mixtures of Soft Prompts](https://mlsanity.com/paper/2205.11961/) (2022)
- [Decomposed Prompt Tuning via Low-Rank Reparameterization](https://mlsanity.com/paper/2310.10094/) (2023)
- [Enhancing Few-Shot Transfer Learning with Optimized Multi-Task Prompt Tuning through Modular Prompt Composition](https://mlsanity.com/paper/2408.13227/) (2024)

## Abstract (arXiv)

Prompt tuning offers a parameter-efficient way to adapt large pre-trained language models to new tasks, but most existing approaches are designed for single-task settings, failing to share knowledge across related tasks. We propose Cross-task Prompt Tuning (CrossPT), a modular framework for multi-task prompt tuning that enables controlled knowledge transfer while maintaining task-specific specialization. CrossPT decomposes each target prompt into shared, pre-trained source prompts and task-specific private prompts, combined via a learned attention mechanism. To support robust transfer, we systematically investigate key design factors including prompt initialization, balancing shared and private prompts, number of source prompts, learning rates, task prefixes, and label semantics. Empirical results on GLUE and related benchmarks show that CrossPT achieves higher accuracy and robustness compared to traditional prompt tuning and related methods, particularly in low-resource scenarios, while maintaining strong parameter efficiency.