Merrill F. Garrett

Syntactically based sentence processing classes: Evidence from event-related brain potentials

Theoretical considerations and diverse empirical data from clinical, psycholinguistic, and developmental studies suggest that language comprehension processes are decomposable into separate subsystems, including distinct systems for semantic and grammatical processing. Here we report that event-related potentials (ERPs) to syntactically well-formed but semantically anomalous sentences produced a pattern of brain activity that is distinct in timing and distribution from the patterns elicited by syntactically deviant sentences, and further, that different types of syntactic deviance produced distinct ERP patterns. Forty right-handed young adults read sentences presented at 2 words/sec while ERPs were recorded from over several positions between and within the hemispheres. Half of the sentences were semantically and grammatically acceptable and were controls for the remainder, which contained sentence medial words that violated (1) semantic expectations, (2) phrase structure rules, or (3) WH-movement constraints on Specificity and (4) Subjacency. As in prior research, the semantic anomalies produced a negative potential, N400, that was bilaterally distributed and was largest over posterior regions. The phrase structure violations enhanced the N125 response over anterior regions of the left hemisphere, and elicited a negative response (300-500 msec) over temporal and parietal regions of the left hemisphere. Violations of Specificity constraints produced a slow negative potential, evident by 125 msec, that was also largest over anterior regions of the left hemisphere. Violations of Subjacency constraints elicited a broadly and symmetrically distributed positivity that onset around 200 msec. The distinct timing and distribution of these effects provide biological support for theories that distinguish between these types of grammatical rules and constraints and more generally for the proposal that semantic and grammatical processes are distinct subsystems within the language faculty.

Representing the Meanings of Object and Action Words: The Featural and Unitary Semantic Space Hypothesis.

This paper presents the Featural and Unitary Semantic Space (FUSS) hypothesis of the meanings of object and action words. The hypothesis, implemented in a statistical model, is based on the following assumptions: First, it is assumed that the meanings of words are grounded in conceptual featural representations, some of which are organized according to modality. Second, it is assumed that conceptual featural representations are bound into lexico-semantic representations that provide an interface between conceptual knowledge and other linguistic information (syntax and phonology). Finally, the FUSS model employs the same principles and tools for objects and actions, modeling both domains in a single semantic space. We assess the plausibility of the model by showing that it can capture generalizations presented in the literature, in particular those related to category-related deficits, and show that it can predict semantic effects in behavioral experiments for object and action words better than other models such as Latent Semantic Analysis (Landauer & Dumais, 1997) and similarity metrics derived from Wordnet (Miller & Fellbaum, 1991).

Grammatical Gender Is on the Tip of Italian Tongues

To correctly produce words, speakers must have access to three broad classes of information lexical semantics, syntax, and sound structure The relevant information must be organized in ways that permit rapid and accurate retrieval of specific lexical targets Current models of language production do this by a two-stage process The first stage incorporates lexical meanings and syntax, and the second, sound structure We used studies of the tip-of-the-tongue phenomenon (i e, the condition in which a speaker cannot produce a well-known word) to evaluate this organization and in so doing, we provide the first clear experimental evidence for a lexical stage that includes syntax and is distinct from both sound structure and the conceptual correlates of syntactic features.

Subject-verb agreement in Spanish and English: Differences in the role of conceptual constraints

This paper reports studies of subject-verb agreement errors with speakers of Spanish and English; we used a sentence completion task, first introduced by Bock and Miller (1991). In a series of four experiments, we assessed the role of semantic information carried by the sentential subject in the induction of subject-verb agreement errors. For Spanish speakers, a sentence preamble such as la etiqueta score las botellas (the label on the bottles), which is usually interpreted to denote several labels, induced more agreement errors than preambles that normally denote a single entity. This finding replicates previous research with Italian (Vigliocco et al., 1995). English speakers, on the other hand, were not sensitive to this semantic dimension, as was found earlier by Bock and Miller (1991). This cross-linguistic difference is discussed in the framework of a modified version of the computational model of grammatical encoding proposed by Kempen and Hoenkamp (1987). In this version of the model agreement is computed through a unification operation instead of feature-copying, allowing for an independent retrieval of agreement features from the conceptual representation for the subject and the verb. We propose that languages differ in the extent to which the selection of the verb is controlled by features on the subject and features from the conceptual representation.

Disorders of lexical selection

Errors in lexical processing are commonplace in language pathologies resulting from brain injury or disease. This discussion considers some of the major recent developments in the interpretation of such errors. The focus is on behavioral systems, rather than neuroanatomical or neurophysiological issues. The objective is to comment on some plausible mutual implications of generally attested pathologies and normal models of lexical retrieval for production, particularly with respect to the roles of semantic and syntactic categories.

Exploring the Activation of Semantic and Phonological Codes during Speech Planning with Event-Related Brain Potentials

We present a new technique for studying the activation of semantic and phonological codes in speech planning using event-related brain potentials (ERPs) that extend a well-established behavioral procedure from speech production research. It combines a delayed picture-naming task with a priming procedure. While participants prepared the production of a depicted objects name, they heard an auditory target word. If the prepared picture name and the target word were semantically or phonologically related, the ERP waveform to the target word tended less towards the negative when compared to an unrelated control. These effects were widely distributed. By contrast, if participants performed a nonlinguistic task on the depicted object (natural size judgment), the semantic effect was still obtained while the phonological effect disappeared. This suggests that the former effect indexes semantic activation involved in object processing while the latter effect indexes word-form activation specific to lexical processing. The data are discussed in the context of models of lexical access in speech production.

The Relation Between Gender and Number Agreement Processing

We report an experiment in which we test the relationship between gender and number in subject-predicate agreement. We also test the link between two different number-agreement relations—subject-verb and subject-predicative adjective. Participants saw first an unmarked adjective and then a sentence fragment consisting of a complex subject with a head noun and a modifier containing a second noun and were asked to make a whole sentence using the adjective with the proper gender and number markings. The gender of the subject head and the gender and number of the attractor noun were manipulated. Number errors in the verb and number and gender errors in the predicative adjective were measured. The results suggest gender agreement is computed independently of number agreement. In contrast, subject-verb number agreement and subject-predicative adjective number agreement are a unitary process. The implications for psycholinguistic and linguistic theories of gender and number are discussed.

Chapter 2 – Remarks on the Architecture of Language Processing Systems

Publisher Summary This chapter reviews the remarks on the architecture of language processing systems. The chapter highlights some of the recurrent conflicts among experimental outcomes that rely on behavioral indices of parsing. These controversies can be understood in terms of two additional data classes: a recent series of eye-movement studies that supports strong interactive claims on re parsing and an equally recent series of event related potential (ERP) studies that supports modular systems. The chapter analyzes the argument that the various conflicts between empirical findings require a resolution in terms of a filtering model, and sketches the outline of such a proposal. The essential feature of the resolution relies on using the language production system as the source of the apparent conceptual and discourse level constraints on parsing. Any general evaluation of the architecture of language processing systems must address not only the character of language comprehension, but also that of language generation. Language production models must account for the real-time integration of utterance form—in the service of the specific force—of the meaning that a speaker wishes to convey on a given occasion of utterance.

The time course of recovery for grammatical category information during lexical processing for syntactic construction

In the experiments outlined in this article, the authors investigate lexical access processes in language production. In their earlier work, T. Pechmann and D. Zerbst (2002) reported evidence for grammatical category constraints in a picture-word interference task. Although grammatical category information was not activated when subjects produced bare noun descriptions of simple objects, a robust effect arose when the target word had to be embedded in a syntactic frame. The current experiments demonstrate that compilation of a simple noun phrase (NP) yields word class effects in picture-word interference experiments in the same time frame as that generally observed for semantic processing. Most significantly, the effect emerges both in German and English with very similar profiles. On these grounds, it is implausible that the effect depends on syntactic gender activation, because such constraints are lacking in the English language version of the experiments.

Semantic Factors in the Production of Number Agreement

This paper examines the role of semantic factors in the production of subject–verb number agreement. As an ostensibly grammatical process, number agreement provides an interesting case for examining the flow and interaction of semantic and syntactic information through the language-production system. Using a sentence-completion task, agreement errors can be elicited from subjects by presenting them with sentence fragments containing a complex noun-phrase, in which the nonhead noun is plural (e.g., The key to the cabinets...WERE missing.). Previous research has demonstrated that the probability of making an error can be affected by varying the properties of the nouns in the complex noun phrase. By investigating which variables do and do not affect error rates, constraints on the flow of information through the production system can be inferred. In three experiments, we investigated the possible effects of three different semantic manipulations of the nouns in the complex NP: animacy, semantic overlap, and plausibility of modification by the sentence predicate. We found that both animacy and semantic relatedness had reliable effects on error rates, indicating that the mechanism involved in implementing agreement cannot be blind to semantic information. However, the plausibility with which each noun could serve as the subject of the sentence predicate had no effect on error rates. Taken together, these results suggest that while semantic information is visible to the agreement mechanism, there are still constraints on when this information can affect the process. Specifically, it may be the case that only information contained within the complex NP is considered for the purposes of implementing agreement.