Abstract: Recursion stands as a pivotal characteristic defining the essence of human languages. This paper delves into a unique manifestation of recursive structures within these languages, namely category recursion, a phenomenon manifested through the hierarchical embedding of one categorical construct within another of the same kind. Based on a comprehensive review of theoretical advancements and cross-linguistic empirical findings in category recursion research over the past two decades, we propose that research to come should explore how the interface conditions (particularly the syntax-semantics interface and syntax-prosody interface) affects the cognitive processing of recursive structures, particularly the neurocognitive mechanisms in cognitive aging, to provide elucidation of the dynamic evolution of linguistic competence from a lifespan perspective.