Proceedings of the Annual Meeting of the Cognitive Science Society

A defining characteristic of human language is hierarchical recursion. Recursive loops (i.e. relative clauses) in sentencescan either be embedded in a sentence or cross each other. It is still unknown why center-embedded (CE) recursion isubiquitous among natural languages as in The boy A1 the dog A2 chases B2 falls B1 (A1A2B2B1), whereas crossed-dependent (CD) orderings of recursion hardly ever occur (A1A2B1B2). Our account of the preponderance of CE is basedon retrieval mechanisms, especially mechanisms of serial recall. It explains that, under conditions that are characteristicfor sentence comprehension, backward retrieval (retrieving dog(A2) first, and boy(A1) next, as required by CE) optimizesmemory performance as compared to forward retrieval (boy( A1) first, and dog (A2) next, as required by CD). We test thisaccount with independent serial recall data. Our analysis suggests that CE is better molded to human memory for serialrecall than CD.