1. Many studies suggest that the parser makes predictions for upcoming linguistic structure (i.e., ‘look-ahead’), but it remains controversial how much (empty) structure is projected ahead at which point in a sentence: do specific elements function as ‘triggers’ for the projection of rigid syntactic templates? Are templates projected on the basis of any incoming first word of a sentence? Or do we only predict one step ahead, i.e. does the parser generate structure on a node-by-node basis? This study presents results from a Sentence Matching experiment on English (VO) - Dutch (OV) code-switches to discriminate between these approaches. 1. top-down / ‘depth-first’ structure generation This hypothesis predicts that a fully-fledged language-specific syntactic frame is built as soon as the first element of a given sentence becomes available. In terms of RTs, we would thus expect (1a / 2b) < (1b / 2a), because in (1a) and (2b) the word order in the switched clause is congruent with the word order proper to the language in which the subject is expressed. 1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b pilot study: monolingual To make sure that the Sentence Matching method is sensitive to the types of VO/OV word order violations under investigation, a monolingual pilot was carried out with a group of L1 Dutch speakers and a group of L1 English speakers (i.e. 7a < 7b and 8b < 8a). results The [language] of the subject did not affect the preferred word order in the switch (reverse effect:: p <.001 / no interaction) These results are incompatible with a top-down/ depth-first approach to sentence comprehension results English natives did indeed show faster RTs for VO word order and Dutch natives were faster on OV word order. This effect was stronger for the English group (English: p <.0001 / Dutch: p <.01) 1 2 - 4 THE BOY zal lezen het boek De jongen WILL THE BOOK READ VO/O V THE BOY VO INFL V (O) De jongen OV INFL (O) V method: sentence matching Participants were asked to indicate whether two sequentially appearing sentences formed an identical pair or not. Pairs of ungrammatical sentences have been shown to yield slower reaction times (RTs) than pairs of grammatical sentences. There was a 500ms interval between each two sentences that formed a pair. Both sentences remained on the screen for 2400ms. participants Pilot Pilot: 21 native speakers of English + 22 native speakers of Dutch Code-switching experiment Code-switching experiment: 16 Dutch - English ‘balanced’ bilinguals [sentence 1] 500ms [sentence2] conclusions This study shows that code-switching data can provide insight into parsing mechanisms: the results suggest that (empty) syntactic templates are projected ‘ahead’, in a top-down fashion; these projections, however, are triggered by features associated with the (phonological) content of specific syntactic nodes only (here: the inflected verb). These findings are incompatible with narrow interpretations of both ‘depth-first’ top-down approaches and node-by-node incremental accounts of sentence comprehension. Disentangling incremental and top-down parsing: Experimental evidence from VO/OV word order patterns in code-switching De jongenWILLTHE BOOKREAD THE BOYzalhet boeklezen De jongenzalTHE BOOKREAD THE BOYWILLhet boeklezen De jongenzalhet boekREAD THE BOYWILLTHE BOOKlezen De jongenzalhet boeklezen THE BOYWILLTHE BOOKREAD SAuxOV 3. incremental/node-by-node structure generation A node-by-node approach to structure building entails that the parser adjusts its predictions for the nature of an upcoming element with each incoming word, as illustrated in steps 1-4. Thus, in the present study, the Dutch - English switches (5a & 5b) should yield faster RTs than the English - Dutch switches (6a & 6b) results (1) \ There was no significant effect of the directionality of the switch, i.e. Dutch - English switches did not yield faster RTs than English - Dutch switches. These results are incompatible with a strict node-by-node approach to sentence comprehension. results (2) \ was There was an interaction between word order and switching pattern, approaching significance (p =.06): OV was preferred for Dutch - English switches (5) and VO for English - Dutch switches (6). This effect pairs with the results obtained for the (3-4) conditions (see 2). Since there was no effect of the [language] of the subject (see 1), it must be an effect of INFL. 12 3 4 THE BOY WILL lezen *O De jongen zal het boek V De jongen zal READ O THE BOY INFL De jongen INFL THE BOY WILL V / *O De jongen zal O / V De jongen zal het boek READ De jongen zal READ het boek Thus, the combined results support a top-down / ‘selective’ approach to structure building. De jongenWILLREADTHE BOOK THE BOYzallezenhet boek De jongenzalREADTHE BOOK THE BOYWILLlezenhet boek De jongenzalREADhet boek THE BOYWILLlezenTHE BOOK De jongenzallezenhet boek THE BOYWILLREADTHE BOOK. SAuxVO 2. top-down / ’selective’ structure generation Under this hypothesis, we expect a language-specific syntactic frame to be projected as soon as certain features, associated with the linguistic content of a specific node, become available. Conditions (3 – 4) test whether these features are associated with the auxiliary (INFL). If so, we should find the RT-pattern (3a / 4b) < (3b / 4a), as illustrated in the trees below. results DID The [language] of the auxiliary DID affect the preferred word order in the switch (p <.01 / no interaction) These results are compatible with a top-down / ‘selective’ approach to sentence comprehension. THE BOY WILL VO V (O) THE BOY WILL VO V (O) De jongen zal OV (O) V De jongen zal OV (O) V 2 1 3 - 4 THE BOY INFL THE BOY INFL De jongen INFL De jongen INFL VO/OV THE BOY WILL VO lezen het boek THE BOY WILL VO lezen het boek De jongen zal OV THE BOOK READ De jongen zal OV THE BOOK READ Suzanne Dikker 1 & Peter Indefrey 2 (1) Department of Linguistics, New York University (2) Max Planck Institute for Psycholinguistics