AI & Computational Science

Neural networks hit fundamental limits in how much they can remember

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This study examines how Kernel Logistic Regression-trained Hopfield networks store and retrieve information, focusing on the geometric structure of memory attractors and the limits of storage capacity. The researchers found that these networks can store random patterns at a ratio of approximately 16 patterns per neuron, and up to 20 for structured data like images, with memory retrieval failure occurring not due to insufficient separation in feature space but from dynamical instability caused by interference between stored patterns. The attractor basins are separated by sharp boundaries resembling phase transitions, and the networks operate near a critical point of dynamical collapse.


These findings provide fundamental insights into designing more robust artificial memory systems and associative neural networks, potentially improving applications in pattern recognition, content-addressable memory, and AI systems that require efficient storage and retrieval of large amounts of information.


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arXiv:2605.00366v4 Announce Type: replace-cross
Abstract: High-capacity associative memories based on Kernel Logistic Regression (KLR) exhibit strong storage capabilities, but the dynamical and geometric mechanisms underlying their stability remain poorly understood. This paper investigates the global geometry of attractor basins and the mechanisms governing the storage limit in KLR-trained Hopfield networks. We combine empirical evaluations using random sequences and real-world image embeddings (CIFAR-10) with morphing experiments and statistical Signal-to-Noise Ratio (SNR) analysis. Our experiments show that the network achieves a storage capacity for random sequences up to $P/N approx 16$, while maintaining stable retrieval for structured data at effective loads near $P/N approx 20$. Morphing analysis indicates that attractors on the “Ridge of Optimization” are separated by sharp, phase-transition-like boundaries, characterized by steep effective potential barriers and critical slowing down. Furthermore, by comparing an SNR analysis with a geometric reference point inspired by Cover’s theorem, we show that the practical storage limit is governed primarily not by a lack of geometric separability in the feature space, but by the loss of dynamical stability against crosstalk noise. These findings suggest that KLR networks function as highly localized exemplar-based memories that operate near the onset of dynamical collapse, providing a useful perspective on the design of robust, large-scale retrieval systems.

Source: Geometric and dynamical analysis of attractor boundaries and storage limits in kernel Hopfield networks