During language acquisition children generalise at multiple layers of granularity. Ambridge argues that abstraction-based accounts suffer from lumping (over-general abstractions) or splitting (over-precise abstractions). Ambridge argues that the only way to overcome this conundrum is in a purely exemplar/analogy-based system in which generalisations are based on similarity to individual exemplars. However, to move our understanding forward, radical exemplar theory must include clearly specified mechanisms for analogy and similarity computation, and must account for changes in children's generalisations across development. [For Ben Ambridge's "Against Stored Abstractions: A Radical Exemplar Model of Language Acquisition," see EJ1269951.]