Model interpretation and explanation

Impossibility

Integrated gradients

Ancona et al. (2017);Sundararajan, Taly, and Yan (2017) Captum implementation seems neat.

When do neurons mean something?

• Toy Models of Superposition

  It would be very convenient if the individual neurons of artificial neural networks corresponded to cleanly interpretable features of the input. For example, in an “ideal” ImageNet classifier, each neuron would fire only in the presence of a specific visual feature, such as the color red, a left-facing curve, or a dog snout. Empirically, in models we have studied, some of the neurons do cleanly map to features. But it isn’t always the case that features correspond so cleanly to neurons, especially in large language models where it actually seems rare for neurons to correspond to clean features. This brings up many questions. Why is it that neurons sometimes align with features and sometimes don’t? Why do some models and tasks have many of these clean neurons, while they’re vanishingly rare in others?

Incoming

• Saphra, Interpretability Creationism

  […] Stochastic Gradient Descent is not literally biological evolution, but post-hoc analysis in machine learning has a lot in common with scientific approaches in biology, and likewise often requires an understanding of the origin of model behavior. Therefore, the following holds whether looking at parasitic brooding behavior or at the inner representations of a neural network: if we do not consider how a system develops, it is difficult to distinguish a pleasing story from a useful analysis. In this piece, I will discuss the tendency towards “interpretability creationism” – interpretability methods that only look at the final state of the model and ignore its evolution over the course of training—and propose a focus on the training process to supplement interpretability research.

  Relation to ablation studies.

• “Understanding RL Vision”

  Interpretable features tend to arise (at a given level of abstraction) if and only if the training distribution is diverse enough (at that level of abstraction).

• Toy Models of Superposition

  It would be very convenient if the individual neurons of artificial neural networks corresponded to cleanly interpretable features of the input. For example, in an “ideal” ImageNet classifier, each neuron would fire only in the presence of a specific visual feature, such as the color red, a left-facing curve, or a dog snout. Empirically, in models we have studied, some of the neurons do cleanly map to features. But it isn’t always the case that features correspond so cleanly to neurons, especially in large language models where it actually seems rare for neurons to correspond to clean features. This brings up many questions. Why is it that neurons sometimes align with features and sometimes don’t? Why do some models and tasks have many of these clean neurons, while they’re vanishingly rare in others?

• Interpretable Machine Learning

• Captum · Model Interpretability for PyTorch

• George Hosu, A Parable Of Explainability

• Connection to Gödel: Mathematical paradoxes demonstrate the limits of AI (Colbrook, Antun, and Hansen 2022; Heaven 2019)

• Frequently I need the link to LIME, a neat model that uses penalised regression to do local model explanations. (Ribeiro, Singh, and Guestrin 2016) See their blog post.

• A cousin of LIME but for tree classifiers is SHAP

• The deep dream “activation maximisation” images could sort of be classified as a type of model explanation, e.g. Multifaceted neuron visualization (Nguyen, Yosinski, and Clune 2016)

• Belatedly I notice that the Data Skeptic podcast did a whole season on interpretability

• How explainable artificial intelligence can help humans innovate

• explainability trade-offs

  • Cassie Kozyrkov, Explainable AI won’t deliver. Here’s why.
  • Wolters Kluwer, peeking into the black box a design perspective on comprehensible ai part 1
  • Rudin (2019) argues the opposite.

• Interpretable Machine Learning Book

• Are Model Explanations Useful in Practice? Rethinking How to Support Human-ML Interactions.

  Existing XAI methods are not useful for decision-making. Presenting humans with popular, general-purpose XAI methods does not improve their performance on real-world use cases that motivated the development of these methods. Our negative findings align with those of contemporaneous works.

References