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arXiv · 2209.10652

Toy Models of Superposition

Nelson Elhage·Tristan Hume·Catherine Olsson·Nicholas Schiefer·Tom Henighan·Shauna Kravec·Zac Hatfield-Dodds·Robert Lasenby·Dawn Drain·Carol Chen·Roger Grosse·Sam McCandlish·Jared Kaplan·Dario Amodei·Martin Wattenberg·Christopher Olah
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Abstract

Neural networks often pack many unrelated concepts into a single neuron - a puzzling phenomenon known as 'polysemanticity' which makes interpretability much more challenging. This paper provides a toy model where polysemanticity can be fully understood, arising as a result of models storing additional sparse features in "superposition." We demonstrate the existence of a phase change, a surprising connection to the geometry of uniform polytopes, and evidence of a link to adversarial examples. We also discuss potential implications for mechanistic interpretability.

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Nelson Elhage, Tristan Hume, Catherine Olsson, Nicholas Schiefer, Tom Henighan, Shauna Kravec, Zac Hatfield-Dodds, Robert Lasenby, Dawn Drain, Carol Chen, Roger Grosse, Sam McCandlish, Jared Kaplan, Dario Amodei, Martin Wattenberg, Christopher Olah. 2022-09-21. Toy Models of Superposition. https://arxiv.org/abs/2209.10652

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