CCN 2026 | Tutorial: Adaptive, degenerate, and yet comparable?

CCN 2026 | Tutorial: Adaptive, degenerate, and yet comparable?

🎙 Erin Grant, Lukas Braun, Eleanor Holton, Marvin Theiss 👥 4K 📅 August 12, 2026 ⏱ 114 min 👁 48 📄 tutorial 🧭 2026-08-15
Available in: English (current) Français

Keywords

representational geometrydegeneracyneural networksrepresentational similaritylinear networks

Summary

This tutorial from CCN 2026 addresses the challenges of comparing neural representations across biological and artificial systems. The presenters, Lukas Braun, Marvin Theiss, and Eleanor Holton, introduce the concepts of adaptivity and degeneracy in neural networks, showing that many distinct network configurations can implement the same function. Using simple two-layer linear networks, they demonstrate that function and representation are dissociable: the same function can be implemented with different hidden representations, and the same representation can support different functions. They formalize this using parameter symmetries and equivalent sets in weight space. The tutorial extends these ideas to deep nonlinear networks and discusses the implications for representational comparisons. They argue that representational similarity alone is not a reliable measure of computational similarity, and propose the study of ‘representational plurality’ as a more meaningful goal. The tutorial includes interactive figures to build intuition and concludes with a discussion of how to identify and investigate representational plurality through task design and behavioral readouts.

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Critical Evaluation

Value of the Information & Strength of the Argument

The tutorial provides a rigorous and accessible introduction to the theoretical underpinnings of representational comparisons. The value lies in its clear demonstration, through simple linear networks, of the dissociation between function and representation, which is a fundamental challenge for the field. The argumentation is solid, building from basic multiplication to matrix transformations and Gram matrices, and is supported by interactive visualizations that allow participants to manipulate parameters and observe the effects. The presenters effectively convey the counterintuitive idea that representational geometry is not uniquely determined by function, and they provide a theoretical framework for understanding when representational comparisons are meaningful. The tutorial successfully bridges theory and practice, offering a compelling case for studying representational plurality.

Scientific Rigor, Source Quality, Title Accuracy

The tutorial is based on a peer-reviewed paper (referenced in the description) and presents original theoretical results. The sources are of high quality, and the content is consistent with current literature in computational neuroscience and machine learning. The title accurately reflects the content, and the tutorial is well-structured. The presenters do not cite external sources during the talk, but the paper provides a solid foundation. The interactive figures are well-designed and enhance understanding. Overall, the scientific rigor is high, and the tutorial is a valuable resource for researchers in the field.

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Title / Content Match

The title accurately reflects the content: the tutorial addresses the challenges of representational comparisons in adaptive and degenerate neural networks, and the subtitle 'Rethinking representational comparisons' is well matched.

Quality & Reliability

8/10

The tutorial is grounded in a peer-reviewed paper and presents rigorous mathematical derivations and interactive demonstrations. The content is consistent with current theoretical neuroscience and machine learning literature. The presentation is clear and the interactive figures enhance understanding. Minor limitations include the lack of direct citations to external sources during the talk and the reliance on simplified linear models, but the theoretical framework is solid.

Key Moments

Cited Sources

Concurring Sources

Contribution & Novelties

The tutorial provides a novel pedagogical approach to understanding the dissociation between function and representation in neural networks, using simple linear models to build intuition. It introduces the concept of ‘representational plurality’ as a central object of study, arguing that representational comparisons should focus on the diversity of neural geometries that support identical behavior. The interactive figures are a valuable resource for researchers and students. The tutorial extends existing theoretical work to practical implications for experimental design.

Pour aller plus loin :

  • Representational similarity analysis — A key method for comparing neural representations, directly relevant to the tutorial’s topic.
  • Degeneracy in neuroscience — The concept of degeneracy in biological systems, which underpins the tutorial’s argument.
  • Neural network parameter symmetries — A paper on symmetries in neural network loss landscapes, relevant to the theoretical foundations.
  • Deep linear networks — A reference on the theory of deep linear networks, which are used in the tutorial.

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Radar Profile

The radar profile shows high scores in quantity and quality of information, indicating a content-rich and well-presented tutorial. The technical level is high, reflecting the advanced nature of the material. The overall reliability is strong, supported by the peer-reviewed basis. The profile suggests a balanced and rigorous educational resource.

Reliability 8/10