How does your brain represent a dog, a chair, or an idea? Scientists have long used similarity comparisons—for example, how similar a brain response is to different images—to study representations. But these methods often leave hidden dimensions unexplored. A new paper introduces Similarity-Based Representation Factorization (SRF), a computational method that recovers the core, interpretable dimensions driving these representations.
The research
Florian P. Mahner and colleagues from the National Institutes of Health and Yale University developed SRF to extract low-dimensional, non-negative embeddings from similarity matrices—tables that capture how similar stimuli are to each other in neural activity, behavior, or AI models. They tested SRF on simulations and nine diverse datasets spanning human fMRI, monkey electrophysiology, behavioral judgments, and deep neural networks. Across all domains, SRF recovered dimensions that matched those from specialized models (e.g., object shape or color), predicted independent behavioral ratings, and improved exploratory analysis. Even with sparse data (as low as 10% of similarity pairs), SRF outperformed standard similarity-matrix comparisons, offering up to 2x higher statistical power for hypothesis testing.
Why it matters
Understanding the hidden dimensions of your cognition—like how your brain organizes objects by function or visual features—can reveal why you think, learn, and remember the way you do. For IQ test fans, SRF could lead to better assessments that measure not just raw ability but the underlying cognitive structures. It also helps explain why AI and human brains sometimes align (e.g., both recognize a cat) and sometimes diverge.
What you can do
While SRF is a research tool, you can apply its principle: reflect on how you categorize things. Are you grouping by purpose or by appearance? Try sorting a random set of objects (e.g., around your room) into piles—this reveals your personal representational dimensions. To measure your overall cognitive abilities, try iqgenio's free test.
Source: arXiv q-bio.NC
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