Graph Structure Prompt Learning: A Novel Methodology to Improve Performance of Graph Neural Networks
Zhenhua Huang, Kunhao Li, Shaojie Wang, Zhaohong Jia, Wentao Zhu, Sharad Mehrotra
TL;DR
This work addresses the limitation that graph neural networks often neglect intrinsic graph structure during task-driven training, leading to suboptimal representations. It introduces Graph Structure Prompt Learning (GPL), a training-time framework that adds task-independent losses, specifically first-order ($\mathcal{L}_{1st}$) and second-order ($\mathcal{L}_{2nd}$) graph-structure prompts, to guide GNNs toward richer structural understanding without requiring additional data or pretraining. GPL is demonstrated to improve node classification, graph classification, and edge prediction across eleven real-world datasets, achieving notable gains and sometimes new state-of-the-art performance, while mitigating over-smoothing. The approach is model-agnostic and practical, offering a new direction for enhancing GNNs with structural prompts and broad potential impact across domains that rely on graph representations.
Abstract
Graph neural networks (GNNs) are widely applied in graph data modeling. However, existing GNNs are often trained in a task-driven manner that fails to fully capture the intrinsic nature of the graph structure, resulting in sub-optimal node and graph representations. To address this limitation, we propose a novel Graph structure Prompt Learning method (GPL) to enhance the training of GNNs, which is inspired by prompt mechanisms in natural language processing. GPL employs task-independent graph structure losses to encourage GNNs to learn intrinsic graph characteristics while simultaneously solving downstream tasks, producing higher-quality node and graph representations. In extensive experiments on eleven real-world datasets, after being trained by GPL, GNNs significantly outperform their original performance on node classification, graph classification, and edge prediction tasks (up to 10.28%, 16.5%, and 24.15%, respectively). By allowing GNNs to capture the inherent structural prompts of graphs in GPL, they can alleviate the issue of over-smooth and achieve new state-of-the-art performances, which introduces a novel and effective direction for GNN research with potential applications in various domains.
