title: Implicit acquisition of grammars with crossed and nested non-adjacent dependencies: investigating the push-down stack model.
abstract: A recent hypothesis in empirical brain research on language is that the fundamental difference between animal and human communication systems is captured by the distinction between finite-state and more complex phrase-structure grammars, such as context-free and context-sensitive grammars. However, the relevance of this distinction for the study of language as a neurobiological system has been questioned and it has been suggested that a more relevant and partly analogous distinction is that between non-adjacent and adjacent dependencies. Online memory resources are central to the processing of non-adjacent dependencies as information has to be maintained across intervening material. One proposal is that an external memory device in the form of a limited push-down stack is used to process non-adjacent dependencies. We tested this hypothesis in an artificial grammar learning paradigm where subjects acquired non-adjacent dependencies implicitly. Generally, we found no qualitative differences between the acquisition of non-adjacent dependencies and adjacent dependencies. This suggests that although the acquisition of non-adjacent dependencies requires more exposure to the acquisition material, it utilizes the same mechanisms used for acquiring adjacent dependencies. We challenge the push-down stack model further by testing its processing predictions for nested and crossed multiple non-adjacent dependencies. The push-down stack model is partly supported by the results, and we suggest that stack-like properties are some among many natural properties characterizing the underlying neurophysiological mechanisms that implement the online memory resources used in language and structured sequence processing.
authors.affiliation: Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands. julia.udden@ki.se
authors.forename: Julia
authors.initials: J
authors.lastname: Uddén
authors.forename: Martin
authors.initials: M
authors.lastname: Ingvar
authors.forename: Peter
authors.initials: P
authors.lastname: Hagoort
authors.forename: Karl M
authors.initials: KM
authors.lastname: Petersson
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007802:Language; D007858:Learning; D008297:Male; D008568:Memory; D008960:Models, Psychological