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Research paperLarge Language Models · Reasoning & Planning1 source · Oct 8, 2026

Looking Inside LLMs: Small-World Connectivity as a Signature of Reasoning Performance

Inspired by neuroscience findings linking higher intelligence to stronger small-world organization in functional brain networks, we investigate small-world connectivity as a structural signature of LLM reasoning.

Key points

  • Understanding large language model (LLM) reasoning requires looking beyond behavioral performance to examine how reasoning ability is reflected in internal organization.
  • We construct functional graphs from attention-head activation similarities and find that a higher small-world index (SWI), capturing local clustering and short global paths, consistently correlates with better fluid reasoning performance across models and training checkpoints.
  • Since local clustering is central to small-world organization, we further examine how heads important for model performance connect within and across communities.
  • We validate this hypothesis through pruning, introducing Small-World Allocation (SWA), a hierarchical sparsity allocation method guided by these scores.

Sources (1)

  • [1]Looking Inside LLMs: Small-World Connectivity as a Signature of Reasoning Performance
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 8, 04:53 PM
    Inspired by neuroscience findings linking higher intelligence to stronger small-world organization in functional brain networks, we investigate small-world connectivity as a structural signature of LLM reasoning.
    Understanding large language model (LLM) reasoning requires looking beyond behavioral performance to examine how reasoning ability is reflected in internal organization.

Extractive summary: sentences quoted from the sources.