Brenda Rapp

The multiple semantics hypothesis: Multiple confusions?

Abstract In this paper we discuss the issue of multiple versus unitary semantics. We argue that the notion of multiple semantics (as currently articulated) does not, in fact, represent a theory of semantic organisation but is, instead, an arbitrary conjunction of a set of independent assumptions which are either unmotivated or, if motivated, equally compatible with a unitary semantics hypothesis. Furthermore, the empirical evidence that has been cited as support for this hypothesis is equally compatible with variants of the unitary semantics hypothesis. A model of semantic processing—the Organised Unitary Content Hypothesis (O.U.C.H.)—that is able to account for reported patterns of dissociation of performance is discussed briefly.

Discreteness and interactivity in spoken word production.

Five theories of spoken word production that differ along the discreteness-interactivity dimension are evaluated. Specifically examined is the role that cascading activation, feedback, seriality, and interaction domains play in accounting for a set of fundamental observations derived from patterns of speech errors produced by normal and brain-damaged individuals. After reviewing the evidence from normal speech errors, case studies of 3 brain-damaged individuals with acquired naming deficits are presented. The patterns these individuals exhibit provide important constraints on theories of spoken naming. With the help of computer simulations of the 5 theories, the authors evaluate the extent to which the error patterns predicted by each theory conform with the empirical facts. The results support a theory of spoken word production that, although interactive, places important restrictions on the extent and locus of interactivity.

Selective impairment of semantics in lexical processing

Abstract We report the performance of a neurologically impaired patient, KE, whose frequent errors in reading, writing, naming, and comprehension were nearly always semantically related to the target response. To quantify this pattern, a large number of items were presented for tasks of verbal and written naming, oral reading, writing to dictation, word/picture matching, and naming from tactile exploration. Detailed analyses of his performance on these tasks show very similar rates and types of errors, regardless of the modality of stimulus or response. KEs homogeneous pattern of semantic errors across modalities is interpreted as evidence for selective damage to a semantic system common to all lexical processes. In addition, although KE demonstrated some spared knowledge of all items in response to picture stimuli, we were able to interpret all aspects of his performance without resorting to a proposal that there are modality-specific semantic systems. Finally, we show that our interpretation, which ass...

On the distinction between deficits of access and deficits of storage: A question of theory

Abstract In this paper we discuss some aspects of the role of theory in cognitive neuropsychological research. We will consider, in particular, the nature of performance criteria used in classifying patients with acquired cognitive disorders, and we will argue that all such criteria are necessarily theory-laden. This issue will be discussed in the specific context of the putative distinction between patients with access vs. storage deficits (Warrington & Shallice, 1979). We will conclude that although the theoretical distinction between access and storage is potentially an exciting and useful one, the phononema that have been reported are far from compelling. Furthermore, and more importantly, we will argue that the proposal is not supra-theoretical in scope as has been claimed, but rather that its evaluation and verification rely crucially in the theoretical framework within which it is presented.

Lexical and Post-Lexical Phonological Representations in Spoken Production.

Theories of spoken word production generally assume a distinction between at least two types of phonological processes and representations: lexical phonological processes that recover relatively arbitrary aspects of word forms from long-term memory and post-lexical phonological processes that specify the predictable aspects of phonological representations. In this work we examine the spoken production of two brain-damaged individuals. We use their differential patterns of accuracy across the tasks of spoken naming and repetition to establish that they suffer from distinct deficits originating fairly selectively within lexical or post-lexical processes. Independent and detailed analyses of their spoken productions reveal contrasting patterns that provide clear support for a distinction between two types of phonological representations: those that lack syllabic and featural information and are sensitive to lexical factors such as lexical frequency and neighborhood density, and those that include syllabic and featural information and are sensitive to detailed properties of phonological structure such as phoneme frequency and syllabic constituency.

The integration of information across lexical and sublexical processes in spelling

We report on a brain-injured subject, LAT, who made phonologically plausible errors in word spelling (e.g., “bouquet” spelled as BOUKET). Although many of his errors are phonologically plausible they contained low-frequency (yet lexically correct) spellings (/ei/ spelled as ET in BOUK ET). Because these errors are phonologically plausible they do not appear to have been generated by the lexical process, yet because they contain low probability, lexically correct elements they do not appear to be have been generated by the sublexical process. We present analyses that specifically support the conclusion that many of LATs phonologically plausible responses to word stimuli consist of the integrated output of elements generated by both the lexical and sublexical processes. This evidence constitutes strong support for the notion that lexical and sublexical processes share information during the course of spelling a familiar word.

The nature of sublexical orthographic organization: The bigram trough hypothesis examined ☆

Abstract Certain theories of reading assume the representation and manipulation of sublexical entities while others do not. Consistent with the latter, M. Seidenberg (1987, in Attention and performance XII: The psychology of reading . Hillsdale, NJ: Erlbaum; 1989, in Linguistic Structure i in Language Processing . Dordrecht: Kluwer) and M. Seidenberg and J. L. McClelland (1989, Psychological Review , 96 , No. 4, 523–568) have proposed that previously reported effects of syllabic and morphological structure can be best understood as resulting from the common co-occurrence of these sublexical entities and a pattern of bigram frequencies referred to as a “bigram trough.” This claim is examined using lexical decision and illusory conjunction paradigms. The reliable effects of syllabic and morphological structure that are observed cannot, however, be accounted for by the presence or absence of bigram troughs. The implications of such findings for the connectionist theory of reading proposed by M. Seidenberg and J. L. McClelland (op. cit.) are discussed.

Examining the Central and Peripheral Processes of Written Word Production Through Meta-Analysis

Producing written words requires “central” cognitive processes (such as orthographic long-term and working memory) as well as more peripheral processes responsible for generating the motor actions needed for producing written words in a variety of formats (handwriting, typing, etc.). In recent years, various functional neuroimaging studies have examined the neural substrates underlying the central and peripheral processes of written word production. This study provides the first quantitative meta-analysis of these studies by applying activation likelihood estimation (ALE) methods (Turkeltaub et al., 2002). For alphabet languages, we identified 11 studies (with a total of 17 experimental contrasts) that had been designed to isolate central and/or peripheral processes of word spelling (total number of participants = 146). Three ALE meta-analyses were carried out. One involved the complete set of 17 contrasts; two others were applied to subsets of contrasts to distinguish the neural substrates of central from peripheral processes. These analyses identified a network of brain regions reliably associated with the central and peripheral processes of word spelling. Among the many significant results, is the finding that the regions with the greatest correspondence across studies were in the left inferior temporal/fusiform gyri and left inferior frontal gyrus. Furthermore, although the angular gyrus (AG) has traditionally been identified as a key site within the written word production network, none of the meta-analyses found it to be a consistent site of activation, identifying instead a region just superior/medial to the left AG in the left posterior intraparietal sulcus. These meta-analyses and the discussion of results provide a valuable foundation upon which future studies that examine the neural basis of written word production can build.

Selective difficulties with spoken nouns and written verbs: A single case study

Abstract We describe an individual who exhibits greater difficulties in speaking nouns than verbs and greater difficulties in writing verbs than nouns across a range of both single word and sentence production tasks. This double dissociation of grammatical category by modality within a single individual represents an important challenge to the claim that all apparent category grammatical deficits can be reduced to the effects of the various semantic variables. The modality-specific nature of the findings clearly support the representation of grammatical category distinctions at post-semantic levels of representations and processing and they raise a number of questions regarding the specific instantiation of these distinctions within current theoretical frameworks of language production.

The Modality-Specific Organization of Grammatical Categories: Evidence from Impaired Spoken and Written Sentence Production

We describe the case of a brain-damaged individual whose speech is characterized by difficulty with practically all words except for elements of the closed class vocabulary. In contrast, his written sentence production exhibits a complementary impairment involving the omission of closed class vocabulary items and the relative sparing of nouns. On the basis of these differences we argue: (1) that grammatical categories constitute an organizing parameter of representation and/or processing for each of the independent, modality-specific lexicons, and (2) that these observations contribute to the growing evidence that access to the orthographic and phonological forms of words can occur independently.