Transformer FFNs
FFN: Feed-Forward Network
Overview
Transformer FFNs, also called MLPs, transform each token’s representation between attention operations, providing much of a model’s nonlinear processing and capacity. Work studies activation choices such as GELU, SwiGLU, and mixtures of activations, as well as changes to the block itself, including sparse experts, tree routing, low-rank branches, and linear alternatives. Researchers evaluate these designs using language-model loss and downstream benchmarks, and use pruning, probing, causal interventions, and geometric analyses to understand which neurons matter and how FFNs shape representations. A central open tension is how much dense nonlinear computation is needed: sparsity and simplification may reduce cost, but must preserve useful interactions that can vary by layer, token, and task.
Latest papers
42 papers7 papers in the last four weeks, up 40% on the four weeks before. 0.0% of all new papers.