The cerebellum and language: Evidence from patients with cerebellar degeneration

Clinical and imaging studies suggest that the cerebellum is involved in language tasks, but the extent to which slowed language production in cerebellar patients contributes to their poor performance on these tasks is not clear. We explored this relationship in 18 patients with cerebellar degeneration and 16 healthy controls who completed measures of verbal fluency (phonemic and semantic), word stem completion, and oral naming speed. Cerebellar patients showed significantly slower response times when naming common nouns, which correlated with their degree of motor impairment. Patients were significantly impaired on both phonemic and semantic fluency measures compared to controls (p < 0.001), even when naming speed was entered as a covariate (p = 0.03). On the word stem completion task, patients were significantly less accurate (p < 0.001), had more errors due to non-responses (p = 0.008), and were slower to respond (p = 0.036) than controls; group effects were significant for overall accuracy, but not response time, when the effects of naming speed were covaried (p = 0.014). These findings suggest that cerebellar patients’ poorer performance on language tasks cannot be explained solely by slower language production, and that the integrity of cerebellar-prefrontal loops might underlie poorer performance on measures of executive function in cerebellar patients.     

Changing Structures in Midstream: Learning Along the Statistical Garden Path

Previous studies of auditory statistical learning have typically presented learners with sequential structural information that is uniformly distributed across the entire exposure corpus. Here we present learners with nonuniform distributions of structural information by altering the organization of trisyllabic nonsense words at midstream. When this structural change was unmarked by low-level acoustic cues, or even when cued by a pitch change, only the first of the two structures was learned. However, both structures were learned when there was an explicit cue to the midstream change or when exposure to the second structure was tripled in duration. These results demonstrate that successful extraction of the structure in an auditory statistical learning task reduces the ability to learn subsequent structures, unless the presence of two structures is marked explicitly or the exposure to the second is quite lengthy. The mechanisms by which learners detect and use changes in distributional information to maintain sensitivity to multiple structures are discussed from both behavioral and computational perspectives.     

Wittgenstein and contemporary theories of word learning

Wittgenstein's positions on word learning, rules of use, and the impossibility of a private language, as expounded in his Philosophical Investigations, are examined in relation to issues of early child word learning. Current theoretical positions in the cognitivist mode are contrasted with the social cultural pragmatic approach, and each is compared to the principles that Wittgenstein advanced. Bloom's [(2000). How children learn the meanings of words. Cambridge, MA: MIT Press] version of the cognitivist theory rejects most of the principles that Wittgenstein advanced, relying on innate cognitive endowments to explain children's success in word learning, using the word-referent mapping paradigm. Nelson's “use without meaning” and Tomasello's [(2003). Constructing a language: A usage-based theory of language acquisition. Cambridge, MA: Harvard University Press] social-pragmatic model of learning from use are presented as representative of Wittgensteinian principles that meaning exists in and is inferred from the uses of words within communal activities (“language games” in “forms of life”).     

Dual-Route and Connectionist Models: A Step Towards a Combined Model

Current models of word recognition are mainly constructed within the frameworks of either dual-route or connectionist theories. The most important test of a word recognition model is how it succeeds in accounting for various reading behaviors. In the present paper dual-route and connectionist word recognition models are briefly described and evaluated. As a further development of these models, a combined framework is proposed. An amalgamation of the two main types of models might give a more satisfactory account of various phenomena within word recognition.     

Metalexical Awareness: Development, Methodology or Written Language? A Cross-linguistic Comparison

This study explores the ability to access word boundaries of pre-school children, using an on-line methodology (Karmiloff-Smith, Grant, Sims, Jones, & Cockle (1996). Cognition, 58, 197–219.), which has hardly been used outside English-speaking countries. In a cross-linguistic study in the Netherlands and Norway, four and five-year-old children were asked to repeat the last word every time a narrator stopped reading a story. In total 32 target-words were used, both closed and open class words, and both monosyllabic and disyllabic words. The outcomes in both countries were different from those of the original English study (Karmiloff-Smith et al., 1996): four- and five-year-olds were successful in only about 26% of the cases, whereas the success rate in the former English experiment was 75% for the younger and 96% for the older children. No differences were found between age groups and between open and closed class words. This methodology does reveal the ability to access word boundaries, but probably not because of the ease of the on-line methodology in itself, but rather because literacy introduces new representations of language, even in on-line processing. The outcomes implicate that the ability to mark word boundaries does not seem to be a valid indication of who is ready for reading.     

From semantics to syntax and back again: argument structure in the third year of life

An essential part of the human capacity for language is the ability to link conceptual or semantic representations with syntactic representations. On the basis of data from spontaneous production, suggested that young children acquire such links on a verb-by-verb basis, with little in the way of a general understanding of linguistic argument structure. Here, we suggest that a receptive understanding of argument structure--including principles linking syntax and conceptual/semantic structure--appears earlier. In a forced-choice pointing task we have shown that toddlers in the third year of life can map a single scene (involving a novel causative action paired with a novel verb) onto two distinct syntactic frames (transitive and intransitive). This suggests that even before toddlers begin generalizing argument structure in their own speech, they have some representation of conceptual/semantic categories, syntactic categories, and a system that links the two.     

Influence of consonantal context on the reading of vowels: evidence from children

When college students pronounce nonwords, their vowel pronunciations may be affected not only by the consonant that follows the vowel, the coda, but also by the preceding consonant, the onset. We presented the nonwords used by Treiman and colleagues in their 2003 study to a total of 94 first graders, third graders, fifth graders, and high school students to determine when these context influences emerge. According to some theories of reading development, early decoding is characterized by context-free links from graphemes to phonemes. However, we found that even children reading at the first-grade level (6-year-olds) were influenced to some extent by a vowel's context. The effect of context on vowel pronunciation increased in strength up to around the fifth-grade reading level (8- and 9-year-olds), and sensitivity to coda-to-vowel associations emerged no earlier than did sensitivity to onset-to-vowel associations. A connectionist model of reading reproduced this general pattern of increasing context effects as a function of training.     

The use of social and salience cues in early word learning

This article explores young infants' ability to learn new words in situations providing tightly controlled social and salience cues to their reference. Four experiments investigated whether, given two potential referents, 15-month-olds would attach novel labels to (a) an image toward which a digital recording of a face turned and gazed, (b) a moving image versus a stationary image, (c) a moving image toward which the face gazed, and (d) a gazed-on image versus a moving image. Infants successfully used the recorded gaze cue to form new word-referent associations and also showed learning in the salience condition. However, their behavior in the salience condition and in the experiments that followed suggests that, rather than basing their judgments of the words' reference on the mere presence or absence of the referent's motion, infants were strongly biased to attend to the consistency with which potential referents moved when a word was heard.     

Lexical retrieval constrained by sound structure: the role of the left inferior frontal gyrus

Positron emission tomography was used to investigate two competing hypotheses about the role of the left inferior frontal gyrus (IFG) in word generation. One proposes a domain-specific organization, with neural activation dependent on the type of information being processed, i.e., surface sound structure or semantic. The other proposes a process-specific organization, with activation dependent on processing demands, such as the amount of selection needed to decide between competing lexical alternatives. In a novel word retrieval task, word reconstruction (WR), subjects generated real words from heard non-words by the substitution of either a vowel or consonant. Both types of lexical retrieval, informed by sound structure alone, produced activation within anterior and posterior left IFG regions. Within these regions there was greater activity for consonant WR, which is more difficult and imposes greater processing demands. These results support a process-specific organization of the anterior left IFG.     

Dissociations in performance on novel versus irregular items: single-route demonstrations with input gain in localist and distributed models

Four pairs of connectionist simulations are presented in which quasi-regular mappings are computed using localist and distributed representations. In each simulation, a control parameter termed input gain was modulated over the only level of representation that mapped inputs to outputs. Input gain caused both localist and distributed models to shift between regularity-based and item-based modes of processing. Performance on irregular items was selectively impaired in the regularity-based modes, whereas performance on novel items was selectively impaired in the item-based modes. Thus, the models exhibited double dissociations without separable processing components. These results are discussed in the context of analogous dissociations found in language domains such as word reading and inflectional morphology.