Britta Biedermann

The representation of homophones: More evidence from the remediation of anomia

This paper compares two theoretical positions regarding the mental representation of homophones: first, that homophones have one phonological word form but two grammatical representations (lemmas, e.g., Levelt et al., 1999; Dell, 1990), or second, that they have two separate phonological word forms (e.g., Caramazza et al., 2001). The adequacy of these two theoretical accounts for explaining the pattern of generalisation obtained in the treatment of homophone naming in aphasia is investigated. Two single cases are presented, where phonological treatment techniques are used to improve word retrieval. Treatment comprised picture naming of one member of a homophone pair using a phonological cueing hierarchy. A significant improvement in word retrieval was found for both the treated and the untreated homophones, while there was no improvement for phonologically and semantically related controls. It is argued that the data support a shared representation for homophones at the word form level. However, current theories cannot explain the pattern of generalisation found without the addition of a mechanism for repetition priming (e.g., suggested by Wheeldon and Monsell, 1992) and feedback between word form and lemmas to explain the results.

Computational modelling of phonological dyslexia: How does the DRC model fare?

This paper investigates the patterns of reading impairment in phonological dyslexia using computational modelling with the dual-route cascaded model of reading (DRC, Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). Systematic lesioning of nonlexical and phonological processes in DRC demonstrates that different lesions and severity of those lesions can reproduce features of phonological dyslexia including impaired reading of nonwords, relatively spared reading of words, an advantage for reading pseudohomophones. Using the same stimuli for model and for patients, lesions to DRC were also used to simulate the reading accuracy shown by three individuals with acquired phonological dyslexia. No single lesion could replicate the reading performance of all three individuals. In order to simulate reading accuracy for one individual a phonological impairment was necessary (addition of noise to the phoneme units), and for the remaining two individuals an impairment to nonlexical reading procedures (increasing the time interval between each new letter being processed) was necessary. We argue that no single locus of impairment (neither phonological nor nonlexical) can account for the reading impairments of all individuals with phonological dyslexia. Instead, different individuals have different impairments (and combinations of impairments) that together provide the spectrum of patterns found in phonological dyslexia.

The representation of homophones: Evidence from remediation

Background: This single case study examines the linguistic phenomenon of ambiguous spoken words: homophones. In the psycholinguistic research literature the lexicalisation of homophones is the subject of extensive debate. A common assumption is that these words share one word form but have two grammatical representations (lemmas). An opposing view postulates two separate word form entries for homophones - without assuming a lemma level. Aims: The single case study presented here searches for empirical evidence for the representation of homophones using aphasic speech production. Can aphasic speech production give us some evidence regarding how many processing levels have to be completed prior to articulation? Methods & Procedures: A treatment study with MW, a man with global aphasia and severe anomia, is presented. Treatment comprised an intensive picture-naming training with exclusively phonological cues. Naming was facilitated using the following cueing hierarchy: (i) giving the initial phoneme, (ii) tapping the syllable number, and (iii) giving the target word for repetition. How this pure phonological training would affect naming performance of homophones, semantically and phonologically related words, and unrelated words was investigated. Outcomes & Results: The results showed significant short-term, item-specific effects for treated words and generalisation to untreated homophone words alone. The outcome is discussed with reference to the debate regarding homophone production in psycholinguistics and the debate regarding the facilitatory effects of phonological techniques. Conclusions: The results support the two stage model, with only one word form and two lemma entries for homophones. In addition, the outcome of this phonological treatment supports the common assumption that pure word form training rarely results in long-term improvement or generalisation.

The lexical-syntactic representation of number

Number is an important aspect of lexical syntax. While there has been substantial research devoted to number agreement at the level of the sentence, relatively less attention has been paid to the representation of number at the level of individual lexical items. In this paper, we propose a representational framework for the lexical syntax of number in spoken word production that we believe can account for much of the data regarding number in noun and noun phrase production. This framework considers the representation of regular and irregular nouns, and more unusual cases such as pluralia tantum (e.g. scissors), zero plurals (e.g. sheep) and mass nouns (e.g. garlic). We not only address bare noun production but also the production of determiner + noun phrases. While focusing on examples from English, we extend the framework to include languages with grammatical gender such as German.

An Untapped resource : treatment as a tool for revealing the nature of cognitive processes

This paper focuses on the role of treatment in cognitive neuropsychological research, arguing that treatment for cognitive impairments should be viewed as a powerful methodology for developing, evaluating, and extending cognitive theories. We suggest that the key aim of cognitive neuropsychology should be characterized as the use of data from the investigation and treatment of individuals with cognitive disorders to develop, evaluate, and extend theories of normal cognition. To support this assertion, this paper discusses examples of how treatment studies have informed theory. The major methodological tool is generalization logic, both generalization across items and generalization across tasks. However, an alternative is to use case series methodology to test predicted correlations between particular cognitive skills and response to treatment. These methods enable explicit testing of a theory or discrimination between theories, focusing on the nature of cognitive representations, the architecture of the cognitive system, and the acquisition of cognitive skills.

The Influence of plural dominance in aphasic word production

Background: Plural dominance refers to the relative difference between the frequencies of a word in its singular and plural forms. Most of the evidence for theoretical accounts of plural dominance has come from psycholinguistic perception experiments (e.g., Baayen, Burani, & Schreuder, 1996; Baayen, Dijkstra, & Schreuder, 1997; Baayen, Schreuder, & Sproat, 1998). Only a few studies have investigated the production side of dominance, even in unimpaired speakers (e.g., Baayen, Levelt, Schreuder, & Ernestus, 2008). To our knowledge there is only one published neuropsychological study from Luzzatti, Mondini, and Semenza (2001) that uses reading-aloud data from an Italian brain-impaired speaker. Although findings across paradigms are inconsistent, they do indicate that plural-dominant nouns behave differently from singular-dominant nouns, and therefore suggest a difference in representation. Aims: This paper investigates processing of plural nouns in aphasia with a specific focus on effects of dominance. Methods & Procedures: We carried out two single-case studies with two women with aphasia, FME and DRS, who showed word retrieval deficits in picture naming as a result of different underlying functional impairments. The main task of interest was picture naming of single and multiple objects in order to test effects of plural dominance. In addition, word–picture matching tested number representation in comprehension. Outcome & Results: DRS showed a specific morphological impairment with plural marking, whereas FME had no specific morphological deficit. The results are discussed in the framework of current psycholinguistic accounts on the representation and processing of plural nouns (e.g., Levelt, Roelofs, & Meyer, 1999; Schreuder & Baayen, 1995). Conclusions: Different effects of plural dominance shown by both women with aphasia result from different underlying functional deficits, which indicate differences in the representation of plural dominance across processing levels.

Does plural dominance play a role in spoken picture naming? A comparison of unimpaired and impaired speakers

Abstract This study investigates the effect of frequency on plural processing. In particular it explores the effect of relative frequency differences between plurals and their singular forms on the representation of plurals. This paper reports data from a group of thirty-eight unimpaired speakers and compares their spoken picture naming of single and multiple objects to that of two people with acquired language impairments (aphasia). For both participant groups (unimpaired and impaired), we observed two key findings for picture naming: first, plurals that are lower in frequency than their singulars (singular-dominant plurals) are responded to more slowly or with more errors compared to their singulars. Second, for plurals that are higher in frequency than their singulars (plural-dominant plurals), no difference in reaction time or error rate was detected between singulars and plurals. By capitalising on patterns observed in both unimpaired and impaired language processing, this study suggests that plural-dominant plurals are stored differently from singular-dominant plurals.

From "some butter" to "a butter": an investigation of mass and count representation and processing.

This paper investigates the representation of mass and count nouns at the lexical–syntactic level, an issue that has not been addressed to date in psycholinguistic theories. A single case study is reported of a man with aphasia, R.A.P., who showed a countability specific deficit that affected processing of mass noun grammar. R.A.P. frequently substituted mass noun determiners (e.g., some, much) with count noun determiners (e.g., a, many). Experimental investigations determined that R.A.P. had a modality-neutral lexical–syntactic impairment. Furthermore, a series of novel experiments revealed that R.A.P.s processing of mass noun determiners varied depending on how mass nouns were depicted (single vs. multiple depictions) and how congruent these were with the conceptual–semantic information of target determiners (e.g., “some” corresponds to MULTIPLE but not SINGLE concepts). R.A.P.s determiner difficulties emerged only when mass nouns and determiners were number incongruent. The results of this research clearly indicate that nouns are lexical–syntactically specified for countability, but that the derivation of countability can additionally be influenced by conceptual-semantics.

The production of singular- and plural-dominant nouns in Dutch

The role of number dominance (singular vs. plural) in word production has revealed contrasting results in Dutch and English. Here, we compared the production of Dutch regular plural forms that are more frequent than their stems (plural-dominant plurals) to plurals that are less frequent than their stems (singular-dominant plurals) in a spoken picture-naming paradigm. Moreover, the role of inflectional entropy during spoken word production was assessed. The results revealed that singular-dominant singulars were produced significantly faster and more accurately than their corresponding plurals, independently of inflectional entropy. However, the production of plural-dominant plurals and singulars was modulated by inflectional entropy, and a plural disadvantage only found if the inflectional variants were not uniformly distributed. Critically, uniformly distributed variants showed a plural advantage in this condition. Our findings suggest that singular-dominant and plural-dominant plurals are processed differently, which we discuss in the context of morphological processing theories in spoken language production.

Effects of homophony on reading aloud : implications for models of speech production

In this paper we investigate whether homophones have shared (e.g., Dell, 1990; Levelt, Roelofs, & Meyer, 1999) or independent (e.g., Caramazza, Costa, Miozzo, & Bi, 2001) phonological representations. We carried out a homophone reading aloud task with low frequency irregular homophones and matched low frequency irregular non-homophonic controls. The ‘Shared Representation’ view predicted a homophone advantage: homophones should be read faster than their matched controls because the low frequency homophone inherits the frequency of its high frequency partner. The ‘Independent Representation’ view predicted neither an advantage nor a disadvantage: performance should be governed by the homophones specific-word frequency. Results showed that low frequency homophones were read aloud slower than non-homophonic controls. Results were confirmed with an independent database of reading latencies (Balota, Cortese, Hutchison, Neely, Nelson, Simpson, & Treiman, 2002). Additionally, attempts to simulate the homophone disadvantage effect using current computational models of reading aloud were all unsuccessful. The homophone disadvantage effect constitutes, therefore, a new challenge for all computational reading models to date.