arXiv AI By Bowen Shi, Qi Ouyang, Long Qian

Sparsity-driven emergence of functional modularity in multitask neural networks

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The paper demonstrates that applying sparsity-inducing regularization to multitask neural networks encourages the emergence of functional modularity without predefining module boundaries. By profiling multilayer perceptrons and a lightweight transformer, the authors identify compact, task‑selective subnetworks—called functional tokens—that can be selectively retained to preserve specific task performance while degrading others. These tokens tend to form in deeper layers, and their compactness and specialization are influenced by regularization strength, form, and task weighting, while they can be recombined to reconstruct composite computations without retraining.

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