Referential cohesion and logical coherence of narration after closed head injury

A group with closed head injury was compared to neurologically intact controls regarding the referential cohesion and logical coherence of narrative production. A sample of six stories was obtained with tasks of cartoon-elicited story-telling and auditory-oral retelling. We found deficits in the clinical group with respect to referential cohesion, logical coherence, and accuracy of narration. The occurrence of deficits depended on the condition of narrative production and, to some extent, on the particular story used. The primary implications of this study pertain to the attention given by researchers to the feature of discourse production being studied and processing demands of the task.     

Action verbal fluency normative data for the elderly

An emerging body of literature points to the prominent role of the frontal lobes in the retrieval of verbs, whereas production of common and proper nouns arguably is mediated primarily by posterior and anterior temporal regions, respectively. Although the majority of studies examining the neuroanatomic distinctions between verb and noun retrieval have relied on action naming tasks (naming depicted activities, e.g., running) as indicators of verb retrieval abilities, recent studies have utilized an action (verb) verbal fluency measure, the Action Fluency Test (AFT), to assess verb retrieval. Findings from these studies suggest that action fluency is sensitive to the integrity of fronto-subcortical neural circuitry and that it is a valid measure of executive and language functions. The AFT is an easily administered executive function measure, but no normative data for the AFT or other action fluency tasks has been published. This study was undertaken to provide initial AFT normative data for a sample of 145 healthy elderly subjects. As education is significantly correlated with AFT scores, the normative data are stratified by educational level.     

Being seaward-handed: a computational model of the acquisition of language-specific spatial references

Empirical findings of cross-linguistic studies reveal three different frames of spatial reference: intrinsic, relative, and absolute. Of special interest are relative and absolute systems because they have antagonistic logical implications concerning the dependence on standpoint and orientation of the speaker/hearer. On the background of these findings it becomes crucial to show how an agent can form such language-specific spatial representations. In this paper, the system Locator is introduced as a model of concept formation in the spatial domain. It is assumed that an agent creates necessary discriminative features in processes of self-organization and selection and cannot just discover or find them in its environment. A number of simulations show that agents successfully create concepts of either a relative system (German) or an absolute system (Marquesan), relying solely on multimodal input (visual and linguistic).

Contextual control of delay discounting by pathological gamblers

The present study demonstrated the relative impact of gambling and nongambling contexts on the degree of delay discounting by pathological gamblers. We used a delay-discounting task with 20 pathological gamblers in and out of the natural context in which they regularly gambled. For 16 of the 20 participants, it appeared that the difference of context altered the subjective value of delayed rewards, thereby producing relative changes in delay-discounting rates that were generally consistent with a hyperbolic model of intertemporal choice. The current data suggest that empirically derived k values from delay-discounting tasks are context sensitive and are not constant across various settings for the individual. Implications for future transitional research on addictive disorders generally, and gambling specifically, are discussed.     

What does syntax say about space? 2-year-olds use sentence structure to learn new prepositions

Children as young as two use sentence structure to learn the meanings of verbs. We probed the generality of sensitivity to sentence structure by moving to a different semantic and syntactic domain, spatial prepositions. Twenty-six-month-olds used sentence structure to determine whether a new word was an object-category name (This is a corp!) or a spatial-relational term (This is acorp my box!). We argue that children rely on the intimate relationship between nouns in sentences and semantic arguments of predicate terms: Noting that a new word takes noun arguments identifies the new word as a predicate term, and directs the child's attention to relations among its arguments.     

Influence of temporal context on value in the multiple-chains and successive-encounters procedures

This set of studies explored the influence of temporal context across multiple-chain and multiple-successive-encounters procedures. Following training with different temporal contexts, the value of stimuli sharing similar reinforcement schedules was assessed by presenting these stimuli in concurrent probes. The results for the multiple-chain schedule indicate that temporal context does impact the value of a conditioned reinforcer consistent with delay-reduction theory, such that a stimulus signaling a greater reduction in delay until reinforcement has greater value. Further, nonreinforced stimuli that are concurrently presented with the preferred terminal link also have greater value, consistent with value transfer. The effects of context on value for conditions with the multiple-successive-encounters procedure, however, appear to depend on whether the search schedule or alternate handling schedule was manipulated, as well as on whether the tested stimuli were the rich or lean schedules in their components. Overall, the results help delineate the conditions under which temporal context affects conditioned-reinforcement value (acting as a learning variable) and the conditions under which it does not (acting as a performance variable), an issue of relevance to theories of choice.     

Why aren't identical twins linguistically identical? Genetic, prenatal and postnatal factors

Results of twin studies clearly demonstrate that genetic factors play an important role in the rate of language acquisition and linguistic proficiency attained by normal and impaired children and adults [see Stromswold, K. (2001). The heritability of language: A review and meta-analysis of twin, adoption and linkage studies. Language, 77, 647-723.]. That said, twin-based heritability estimates for language rarely exceed .6 and monozygotic (MZ) twins (who are usually assumed to have identical genetic and environmental endowments) sometimes have very different linguistic profiles. In addition, twins are more likely to suffer linguistic delays and impairments than singletons. Postnatal factors, such as differences in linguistic input twins receive, are usually assumed to be the major reason for these findings. This paper discusses how genetic, epigenetic, and perinatal environmental factors can lower heritability estimates for language, cause MZ twins to be linguistically discordant, and increase the risk of language impairments in twins. We present results from our ongoing Perinatal Environment and Genetic Interaction (PEGI) study that suggest that perinatal environmental factors affect linguistic development more than postnatal factors, and that postnatal factors affect cognitive development more than perinatal factors. Because perinatal factors are overwhelming biological, whereas postnatal factors tend to be psychosocial (e.g., how and how much parents speak to their children), these results support nativist/biological theories of language and language development and call into question empiricist/emergentist theories. These results are also consistent with modularist theories of language. We end by suggesting new methods that can be used to tease apart the effects of prenatal and postnatal environment and to investigate how these factors interact with genetic factors.     

Do differences in brain activation challenge universal theories of dyslexia?

It has been commonly agreed that developmental dyslexia in different languages has a common biological origin: a dysfunction of left posterior temporal brain regions dealing with phonological processes. Siok, Perfetti, Jin, and Tan (2004, Nature, 431, 71-76) challenge this biological unity theory of dyslexia: Chinese dyslexics show no deficits in posterior temporal brain regions but a functional disruption of the left middle frontal gyrus. Here, I will argue that these data do not challenge universal cognitive theories of dyslexia according to which weaknesses in the ability to process the phonological features of language are at the origin of dyslexia.     

Errors of Omission in English-Speaking Children's Production of Plurals and the Past Tense: The Effects of Frequency, Phonology, and Competition

How do English‐speaking children inflect nouns for plurality and verbs for the past tense? We assess theoretical answers to this question by considering errors of omission, which occur when children produce a stem in place of its inflected counterpart (e.g., saying “dress” to refer to 5 dresses). A total of 307 children (aged 3;11–9;9) participated in 3 inflection studies. In Study 1, we show that errors of omission occur until the age of 7 and are more likely with both sibilant regular nouns (e.g., dress) and irregular nouns (e.g., man) than regular nouns (e.g., dog). Sibilant nouns are more likely to be inflected if they are high frequency. In Studies 2 and 3, we show that similar effects apply to the inflection of verbs and that there is an advantage for “regular‐like” irregulars whose inflected form, but not stem form, ends in d/t. The results imply that (a) stems and inflected forms compete for production and (b) children generalize both product‐oriented and source‐oriented schemas when learning about inflectional morphology.     

The interpretation of classically quantified sentences: a set-theoretic approach

We present a set-theoretic model of the mental representation of classically quantified sentences (All P are Q, Some P are Q, Some P are not Q, and No P are Q). We take inclusion, exclusion, and their negations to be primitive concepts. We show that although these sentences are known to have a diagrammatic expression (in the form of the Gergonne circles) that constitutes a semantic representation, these concepts can also be expressed syntactically in the form of algebraic formulas. We hypothesized that the quantified sentences have an abstract underlying representation common to the formulas and their associated sets of diagrams (models). We derived 9 predictions (3 semantic, 2 pragmatic, and 4 mixed) regarding people's assessment of how well each of the 5 diagrams expresses the meaning of each of the quantified sentences. We report the results from 3 experiments using Gergonne's (1817) circles or an adaptation of Leibniz (1903/1988) lines as external representations and show them to support the predictions.