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Alfonso Caramazza

Publications and source records attributed to Alfonso Caramazza.

At least 19 recordsLinked to original sources
PubMed2006

Evaluating computational models in cognitive neuropsychology: the case from the consonant/vowel distinction.

Caramazza et al. [Caramazza, A., Chialant, D., Capasso, R., & Miceli, G. (2000). Separable processing of consonants and vowels. Nature, 403(6768), 428-430.] report two patients who exhibit a double dissociation between consonants and vowels in speech production. The patterning of this double dissociation cannot be explained by appealing to sub-phonemic distinctions, such as sonority level or damage to specific phonological features. They argue that consonant/vowel status is an autonomous level of representation. Monaghan and Shillcock [Monaghan, P., & Shillcock, R. (2003). Connectionist modelling of the separable processing of consonants and vowels. Brain and Language, 86(1), 83-98.] present computational models which supposedly exhibit a similar double dissociation. They contend that these models can explain the patient data, without appeal to such supra-phonemic distinctions as consonant/vowel status. Here we argue that their claim fails to meet two necessary criteria. Their models do not fit the pattern of the patient data, either quantitatively or qualitatively. Furthermore, the motivation for these models is unclear beyond just being an attempt to explain this specific phenomenon. We conclude that these models, in their current form, do not provide an alternative explanation to the representation of consonants and vowels.

Aphasia↗
PubMed2006

Cortical signatures of noun and verb production.

Categories like "noun" and "verb" represent the basic units of grammar in all human languages, and the retrieval of categorical information associated with words is an essential step in the production of grammatical speech. Studies of brain-damaged patients suggest that knowledge of nouns and verbs can be spared or impaired selectively; however, the neuroanatomical correlates of this dissociation are not well understood. We used event-related functional MRI to identify cortical regions that were active when English-speaking subjects produced nouns or verbs in the context of short phrases. Two regions, in the left prefrontal cortex and left superior parietal lobule, were selectively activated for verb trials compared with noun trials; one region in the left inferior temporal lobe was more active during noun production than verb production. We propose that these regions are involved in representing core conceptual properties of nouns and verbs.

Adult↗
PubMed2006

Planning at the phonological level during sentence production.

In two picture-word interference experiments we examined whether phrase boundaries affected how far in advance speakers plan the sounds of words during sentence production. Participants produced sentences of varying lengths (short determiner + noun + verb or long determiner + adjective + noun + verb) while ignoring phonologically related and unrelated words to the verb of the sentence. Response times to begin producing both types of sentences were faster in the presence of a related versus unrelated distractor. The results suggest that the activation of phonological properties of words outside the first phrase and first and second phonological word affect onset of articulation during sentence production. The results are discussed in the light of previous evidence of phonological planning during multi-word production. Implications for the phonological facilitation effect in the picture-word interference paradigm are also discussed.

Adult↗
PubMed2006

Now you see it, now you don't: on turning semantic interference into facilitation in a Stroop-like task.

We use a masked priming procedure to test two accounts of the picture-word interference (PWI) effect: the lexical selection by competition account (Levelt et al., 1999; Roelofs, 1992) and the response selection account (Lupker, 1979; Miozzo and Caramazza, 2003). In the visible (standard) condition, we replicated the often-observed semantic interference effect. In the masked condition, we observed semantic facilitation. We take the polarity shift as a function of masking to mean that the semantic interference and semantic facilitation in the PWI task should be attributed to two qualitatively different processes. We argue that this conclusion follows naturally from the response selection account, but only with great difficulty from the lexical selection by competition account.

Adolescent↗
PubMed2006

Lexical selection in bilingual speech production does not involve language suppression.

The "hard problem" in bilingual lexical access arises when translation-equivalent lexical representations are activated to roughly equal levels and, thus, compete equally for lexical selection. The language suppression hypothesis (D. W. Green, 1998) solves this hard problem through the suppression of lexical representations in the nontarget language. Following from this proposal is the prediction that lexical selection should take longer on a language switch trial because the to-be-selected representation was just suppressed on the previous trial. Inconsistent with this prediction, participants took no longer to name pictures in their dominant language on language switch trials than they did on nonswitch trials. These findings indicate that nontarget lexical representations are not suppressed. The authors suggest that these results undermine the viability of the language suppression hypothesis as a possible solution to the hard problem in bilingual lexical access.

Adolescent↗
PubMed2005

Patterns of comprehension performance in agrammatic Broca's aphasia: a test of the Trace Deletion Hypothesis.

We tested the core prediction of the Trace Deletion Hypothesis (TDH) of agrammatic Broca's aphasia, which contends that such patients' comprehension performance is normal for active reversible sentences but at chance level for passive reversible sentences. We analyzed the comprehension performance of 38 Italian Broca's aphasics with verified damage to Broca's area, who completed sentence-to-picture matching tasks using active and passive reversible sentences as stimuli. The results failed to confirm the predictions made by TDH: only a small minority (15%) performed at chance on passive sentences and better than chance on active sentences. Furthermore, the distribution of the 38 subjects' performance on passive sentences differed from that predicted by the TDH since many more subjects performed at better-than-chance levels than expected. We discuss the implication of these results for claims about the distribution of language processing mechanisms in the brain.

Adult↗
PubMed2005

The representation of homophones: evidence from the distractor-frequency effect.

Current models of word production offer different accounts of the representation of homophones in the lexicon. The investigation of how the homophone status of a word affects lexical access can be used to test theories of lexical processing. In this study, homophones appeared as word distractors superimposed on pictures that participants named orally. The authors varied distractor frequency, a variable that has been shown to modulate the interference that distractors produce on picture naming. The results of 3 experiments converged in showing that words interfered in proportion to their individual frequency in the language, even if they have high-frequency homophone mates. This effect of specific-word frequency is compatible with models that assume (a) distinct lexical representations for the individual homophones and (b) that access to such representations is modulated by frequency. The authors discuss the extent to which current models of word production satisfy these constraints.

Attention↗
PubMed2005

On the categorical nature of the semantic interference effect in the picture-word interference paradigm.

Two picture-word interference experiments are reported in which the boundaries of the semantic interference effect are explored. In both experiments, participants named pictures (e.g., a picture of a car) that appeared with superimposed word distractors. Distractor words from the same semantic category as the word for the picture (e.g., CAR) produced semantic interference, whereas semantically related distractors from a different category (e.g., BUMPER) led to semantic facilitation. In Experiment 2, the semantic facilitation from semantically related distractors was replicated. These results indicate that a semantic relationship between picture and distractor does not necessarily lead to interference and in fact can lead to facilitation. In all but one case tested until now, a semantic relationship between picture and distractor has led to semantic facilitation. The implications of these results for the assumption that the semantic interference effect arises as a consequence of lexical competition are discussed.

Attention↗
PubMed2004

Dissociating neural correlates for nouns and verbs.

Dissociations in the ability to produce words of different grammatical categories are well established in neuropsychology but have not been corroborated fully with evidence from brain imaging. Here we report on a PET study designed to reveal the anatomical correlates of grammatical processes involving nouns and verbs. German-speaking subjects were asked to produce either plural and singular nouns, or first-person plural and singular verbs. Verbs, relative to nouns, activated a left frontal cortical network, while the opposite contrast (nouns-verbs) showed greater activation in temporal regions bilaterally. Similar patterns emerged when subjects performed the task with pseudowords used as nouns or as verbs. These results converge with findings from lesion studies and suggest that grammatical category is an important dimension of organization for knowledge of language in the brain.

Adult↗
PubMed2004

Regular and irregular morphology and its relationship with agrammatism: evidence from two Spanish-Catalan bilinguals.

We report the performance of two aphasic patients in a morphological transformation task. Both patients are Spanish-Catalan bilingual speakers who were diagnosed with agrammatic Broca's aphasia. In the morphological transformation task, the two patients were asked to produce regular and irregular verb forms. The patients showed poorer performance with irregular than regular morphological transformations in both of their languages. These results are at odds with the proposal that agrammatic speech is always or even preponderantly associated with poorer performance in processing regular versus irregular verb form. Instead, these results support the view that a major component of agrammatic production is a deficit in morphosyntactic processing, independently of whether this processing ultimately involves regular or irregular forms.

Adult↗
PubMed2004

The relationships between morphological and phonological errors in aphasic speech: data from a word repetition task.

Current theories of single-word processing predict that in some cases brain damage should selectively impair morphological processes, resulting in the selective occurrence of morphological errors. However, such a selective pattern of errors has never been documented, and the available case studies report the systematic association of morphological and phonological (segmental) errors in the same subject. The number of relevant case reports is very small, however. To better understand the relationship between morphological and phonological processes, we analyzed the repetition performance of 26 subjects who produced morphological errors in a screening battery for aphasia. Although the results confirm that subjects who make morphological errors also invariably make phonological errors, the probabilities of the two types of errors are not (quantitatively) correlated. Furthermore, the relationship between morphological and phonological errors was asymmetrical: although all subjects who produced morphological errors also produced phonological errors, some aphasics who produced phonological errors did not also produce morphological errors. The one-way relationship between morphological and phonological errors could result either from the anatomical proximity of the structures involved in morphological and phonological processes, or from the functional inseparability of the two processes. The fact that phonological errors can occur either in isolation or in association with morphological errors could be attributed to the functional heterogeneity of phonological errors, and to the separability of the neural substrates involved in processing various aspects of phonological information.

Adult↗
PubMed2004

What determines the speed of lexical access: homophone or specific-word frequency? A reply to Jescheniak et al. (2003).

A. Caramazza, A. Costa, M. Miozzo, and Y. Bi (2001) reported a series of experiments showing that naming latencies for homophones are determined by specific-word frequency (e.g., frequency of nun) and not homophone frequency (frequency of nun + none). J. D. Jescheniak, A. S. Meyer, and W. J. M. Levelt (2003) have challenged these studies on a variety of grounds. Here we argue that these criticisms are not well founded and try to clarify the theoretical issues that can be meaningfully addressed by considering the effects of frequency on homophone production. We conclude that the evidence from homophone production cannot be considered to provide support to 2-layer theories of the lexical system.

Humans↗
PubMed2004

Orthographic structure and deaf spelling errors: syllables, letter frequency, and speech.

Syllable structure influences hearing students' reading and spelling (e.g., Badecker, 1996; Caramazza & Miceli, 1990; Prinzmetal, Treiman, & Rho, 1986; Rapp, 1992; Treiman & Zukowski, 1988). This may seem unsurprising since hearers closely associate written and spoken words. We analysed a corpus of spelling errors made by deaf students. They would have learned English orthography with an attenuated experience of speech. We found that the majority of their errors were phonologically implausible but orthographically legal. A tendency to replace uncommon letter sequences with common sequences could not account for this pattern, nor could residual influence from speech. Since syllabically defined constraints are required to keep sequences orthographically legal, the deaf data are marked by an influence of syllable structure. Two main conclusions follow: (1) Our results contribute to evidence that abstract constraints, not derived from peripheral speech or hearing mechanisms, govern the organization of linguistic knowledge; and (2) statistical redundancy could not explain the deaf results. It does not offer a general alternative to suprasegmental structure.

Adolescent↗
PubMed2004

The categorical distinction of vowel and consonant representations: evidence from dysgraphia.

Subject GSI presents with a graphemic buffer deficit following a massive left fronto-parietal lesion. His errors involved essentially only consonants (98.2%). However, he always spelled correctly the first consonant in a string, and produced steadily increasing numbers of errors on the following consonants, while always spelling all the vowels in the target correctly. The pattern of performance observed in this subject provides strong evidence for the separate (categorical) representation of consonants and vowels, and suggests that working memory interacts with independent consonant and vowel representations in spelling.

Adult↗
PubMed2004

Heterogeneity is a fact of category-specific semantic deficits. so? comments on Rosazza, Imbornone, Zorzi, Farina, Chiavari, And Cappa (2003).

The Sensory/Functional Theory, until recently the received explanation of category-specific semantic deficits, has been shown to be at variance with various facts that have emerged about the nature of these deficits. In this context, Rosazza, Imbornone, Zorzi, Farina, Chiavari, and Cappa (2003: The Heterogeneity of Category-Specific Semantic Disorders: Evidence from a New Case. Neurocase, 9, 189-202.) report the case study of a patient, MA, with a purported category-specific semantic deficit for living things compared to nonliving things, and an associated modality-specific impairment that differentially affected visual/perceptual compared to functional/associative knowledge. While acknowledging that the Sensory/Functional Theory cannot account for the existence of category-specific semantic deficits, Rosazza and colleagues (2003) contend that "...the presence of a more severe loss of specific visual rather than functional knowledge could support an interpretation according to the Sensory/Functional Theory" [sic] (p. 200). Our comments are divided into two parts. First, we point out that there is an asymmetry between evidence and theory: if there is clear evidence that "disconfirms" a given theory, evidence that is consistent with the theory cannot be argued to support the theory. Second, we argue that the performance profile of MA could potentially be relevant to other interpretations of category-specific deficits but that theoretical interpretations of the performance profile of patient MA are undermined by a lack of methodological rigor, as well as the generally weak data associated with the case.

Brain Injuries↗
PubMed2004

All talk and no action: a transcranial magnetic stimulation study of motor cortex activation during action word production.

A number of researchers have proposed that the premotor and motor areas are critical for the representation of words that refer to actions, but not objects. Recent evidence against this hypothesis indicates that the left premotor cortex is more sensitive to grammatical differences than to conceptual differences between words. However, it may still be the case that other anterior motor regions are engaged in processing a word's sensorimotor features. In the present study, we used single- and paired-pulse transcranial magnetic stimulation to test the hypothesis that left primary motor cortex is activated during the retrieval of words (nouns and verbs) associated with specific actions. We found that activation in the motor cortex increased for action words compared with non-action words, but was not sensitive to the grammatical category of the word being produced. These results complement previous findings and support the notion that producing a word activates some brain regions relevant to the sensorimotor properties associated with that word regardless of its grammatical category.

Acoustic Stimulation↗
PubMed2003

Grammatical processing of nouns and verbs in left frontal cortex?

We report the case of a brain-damaged subject R.C. who is more impaired at producing grammatical forms of words and pseudo-words used as verbs (he judges, he wugs) than of the same words used as nouns (the judges, the wugs). This pattern of performance constitutes the first clear demonstration that grammatical knowledge about verbs can be selectively impaired following brain damage. A comparison of R.C.'s behavioral and neurological profile with that of a patient who shows similar difficulties with nouns suggests that nouns and verbs are processed by separate neural systems with components in the left frontal lobe.

Aged↗