Inductive Biases and Variable Creation in Self-Attention Mechanisms
This provides foundational insights into why self-attention works well for long-range dependencies, which is incremental but clarifies theoretical underpinnings for ML/AI researchers.
The paper theoretically analyzes the inductive biases of self-attention mechanisms, showing that Transformer networks can represent sparse functions with sample complexity scaling logarithmically with context length.
Self-attention, an architectural motif designed to model long-range interactions in sequential data, has driven numerous recent breakthroughs in natural language processing and beyond. This work provides a theoretical analysis of the inductive biases of self-attention modules. Our focus is to rigorously establish which functions and long-range dependencies self-attention blocks prefer to represent. Our main result shows that bounded-norm Transformer networks "create sparse variables": a single self-attention head can represent a sparse function of the input sequence, with sample complexity scaling only logarithmically with the context length. To support our analysis, we present synthetic experiments to probe the sample complexity of learning sparse Boolean functions with Transformers.