Publications

Abstract

Survey article

Abstract

Philosophers, psychologists, and linguists have argued that spatial conception is pivotal to cognition in general, providing a general, egocentric, and universal framework for cognition as well as metaphors for conceptualizing many other domains. But in an aboriginal community in Northern Queensland, a system of cardinal directions informs not only language, but also memory for arbitrary spatial arrays and directions. This work suggests that fundamental cognitive parameters, like the system of coding spatial locations, can vary cross-culturally, in line with the language spoken by a community. This opens up the prospect of a fruitful dialogue between anthropology and the cognitive sciences on the complex interaction between cultural and universal factors in the constitution of mind.

Abstract

The apolipoprotein E {varepsilon}4 (APOE {varepsilon}4) is the main known genetic risk factor for Alzheimer's disease. Genetic assessments in combination with other diagnostic tools, such as neuroimaging, have the potential to facilitate early diagnosis. In this large-scale functional MRI (fMRI) study, we have contrasted 30 APOE {varepsilon}4 carriers (age range: 49–74 years; 19 females), of which 10 were homozygous for the {varepsilon}4 allele, and 30 non-carriers with regard to brain activity during a semantic categorization task. Test groups were closely matched for sex, age and education. Critically, both groups were cognitively intact and thus symptom-free of Alzheimer's disease. APOE {varepsilon}4 carriers showed reduced task-related responses in the left inferior parietal cortex, and bilaterally in the anterior cingulate region. A dose-related response was observed in the parietal area such that diminution was most pronounced in homozygous compared with heterozygous carriers. In addition, contrasts of processing novel versus familiar items revealed an abnormal response in the right hippocampus in the APOE {varepsilon}4 group, mainly expressed as diminished sensitivity to the relative novelty of stimuli. Collectively, these findings indicate that genetic risk translates into reduced functional brain activity, in regions pertinent to Alzheimer's disease, well before alterations can be detected at the behavioural level.

Abstract

Classically, infants are thought to point for 2 main reasons: (a) They point imperatively when they want an adult to do something for them (e.g., give them something; “Juice!”), and (b) they point declaratively when they want an adult to share attention with them to some interesting event or object (“Look!”). Here we demonstrate the existence of another motive for infants' early pointing gestures: to inform another person of the location of an object that person is searching for. This informative motive for pointing suggests that from very early in ontogeny humans conceive of others as intentional agents with informational states and they have the motivation to provide such information communicatively

Abstract

The study investigated the neuronal basis of the retrieval of words from the mental lexicon. The semantic category interference effect was used to locate lexical retrieval processes in time and space. This effect reflects the finding that, for overt naming, volunteers are slower when naming pictures out of a sequence of items from the same semantic category than from different categories. Participants named pictures blockwise either in the context of same- or mixedcategory items while the brain response was registered using magnetoencephalography (MEG). Fifteen out of 20 participants showed longer response latencies in the same-category compared to the mixed-category condition. Event-related MEG signals for the participants demonstrating the interference effect were submitted to a current source density (CSD) analysis. As a new approach, a principal component analysis was applied to decompose the grand average CSD distribution into spatial subcomponents (factors). The spatial factor indicating left temporal activity revealed significantly different activation for the same-category compared to the mixedcategory condition in the time window between 150 and 225 msec post picture onset. These findings indicate a major involvement of the left temporal cortex in the semantic interference effect. As this effect has been shown to take place at the level of lexical selection, the data suggest that the left temporal cortex supports processes of lexical retrieval during production.

Abstract

Tests of causal attribution often use verbal vignettes, with covariation information provided through statements quantified with natural language expressions. The effect of covariation information has typically been taken to show that set size information affects attribution. However, recent research shows that quantifiers provide information about discourse focus as well as covariation information. In the attribution literature, quantifiers are used to depict covariation, but they confound quantity and focus. In four experiments, we show that focus explains all (Experiment 1) or some (Experiments 2, 3 and 4) of the impact of covariation information on the attributions made, confirming the importance of the confound. Attribution experiments using vignettes that present covariation information with natural language quantifiers may overestimate the impact of set size information, and ignore the impact of quantifier-induced focus.

Abstract

A key question in categorisation is to what extent people categorise in the same way, or differently. This paper examines categorisation of the body in Punjabi, an Indo-European language spoken in Pakistan and India. First, an inventory of body part terms is presented, illustrating how Punjabi speakers segment and categorise the body. There are some noteworthy terms in the inventory, which illustrate categories in Punjabi that are unusual when compared to other languages presented in this volume. Second, Punjabi speakers’ conceptualisation of the relationship between body parts is explored. While some body part terms are viewed as being partonomically related, others are viewed as being in a locative relationship. It is suggested that there may be key ways in which languages differ in both the categorisation of the body into parts, and in how these parts are related to one another.

Abstract

In previous research it has been shown that subject relative clauses are easier to process than object relative clauses. Several theories have been proposed that explain the difference on the basis of different theoretical perspectives. However, previous research tested relative clauses only with animate protagonists. In a corpus study of Dutch and German newspaper texts, we show that animacy is an important determinant of the distribution of subject and object relative clauses. In two experiments in Dutch, in which the animacy of the object of the relative clause is varied, no difference in reading time is obtained between subject and object relative clauses when the object is inanimate. The experiments show that animacy influences the processing difficulty of relative clauses. These results can only be accounted for by current major theories of relative clause processing when additional assumptions are introduced, and at the same time show that the possibility of semantically driven analysis can be considered as a serious alternative.

Abstract

For several languages, a preference for subject relative clauses over object relative clauses has been reported. However, Mak, Vonk, and Schriefers (2002) showed that there is no such preference for relative clauses with an animate subject and an inanimate object. A Dutch object relative clause as …de rots, die de wandelaars beklommen hebben… (‘the rock, that the hikers climbed’) did not show longer reading times than its subject relative clause counterpart …de wandelaars, die de rots beklommen hebben… (‘the hikers, who climbed the rock’). In the present paper, we explore the factors that might contribute to this modulation of the usual preference for subject relative clauses. Experiment 1 shows that the animacy of the antecedent per se is not the decisive factor. On the contrary, in relative clauses with an inanimate antecedent and an inanimate relative-clause-internal noun phrase, the usual preference for subject relative clauses is found. In Experiments 2 and 3, subject and object relative clauses were contrasted in which either the subject or the object was inanimate. The results are interpreted in a framework in which the choice for an analysis of the relative clause is based on the interplay of animacy with topichood and verb semantics. This framework accounts for the commonly reported preference for subject relative clauses over object relative clauses as well as for the pattern of data found in the present experiments.

Abstract

We describe a family-based sample of individuals with reading disability collected as part of a quantitative trait loci (QTL) mapping study. Eighty-nine nuclear families (135 independent sib-pairs) were identified through a single proband using a traditional discrepancy score of predicted/actual reading ability and a known family history. Eight correlated psychometric measures were administered to each sibling, including single word reading, spelling, similarities, matrices, spoonerisms, nonword and irregular word reading, and a pseudohomophone test. Summary statistics for each measure showed a reduced mean for the probands compared to the co-sibs, which in turn was lower than that of the population. This partial co-sib regression back to the mean indicates that the measures are influenced by familial factors and therefore, may be suitable for a mapping study. The variance of each of the measures remained largely unaffected, which is reassuring for the application of a QTL approach. Multivariate genetic analysis carried out to explore the relationship between the measures identified a common factor between the reading measures that accounted for 54% of the variance. Finally the familiality estimates (range 0.32–0.73) obtained for the reading measures including the common factor (0.68) supported their heritability. These findings demonstrate the viability of this sample for QTL mapping, and will assist in the interpretation of any subsequent linkage findings in an ongoing genome scan.

Abstract

Two eye-monitoring studies examined when unexpressed schematic participant information specified by verbs is used during sentence processing. Experiment 1 compared the processing of sentences with passive and intransitive verbs hypothesized to introduce or not introduce, respectively, an agent when their main clauses were preceded by either agent-dependent rationale clauses or adverbial clause controls. While there were no differences in the processing of passive clauses following rationale and control clauses, intransitive verb clauses elicited anomaly effects following agent-dependent rationale clauses. To determine whether the source of this immediately available schematic participant information is lexically specified or instead derived solely from conceptual sources associated with verbs, Experiment 2 compared the processing of clauses with passive and middle verbs following rationale clauses (e.g., To raise money for the charity, the vase was/had sold quickly…). Although both passive and middle verb forms denote situations that logically require an agent, middle verbs, which by hypothesis do not lexically specify an agent, elicited longer processing times than passive verbs in measures of early processing. These results demonstrate that participants access and interpret lexically encoded schematic participant information in the process of recognizing a verb.

Abstract

A perceptual learning experiment provides evidence that the mental lexicon cannot consist solely of detailed acoustic traces of recognition episodes. In a training lexical decision phase, listeners heard an ambiguous [f–s] fricative sound, replacing either [f] or [s] in words. In a test phase, listeners then made lexical decisions to visual targets following auditory primes. Critical materials were minimal pairs that could be a word with either [f] or [s] (cf. English knife–nice), none of which had been heard in training. Listeners interpreted the minimal pair words differently in the second phase according to the training received in the first phase. Therefore, lexically mediated retuning of phoneme perception not only influences categorical decisions about fricatives (Norris, McQueen, & Cutler, 2003), but also benefits recognition of words outside the training set. The observed generalization across words suggests that this retuning occurs prelexically. Therefore, lexical processing involves sublexical phonological abstraction, not only accumulation of acoustic episodes.

Abstract

The speech perception system must be flexible in responding to the variability in speech sounds caused by differences among speakers and by language change over the lifespan of the listener. Indeed, listeners use lexical knowledge to retune perception of novel speech (Norris, McQueen, & Cutler, 2003). In that study, Dutch listeners made lexical decisions to spoken stimuli, including words with an ambiguous fricative (between [f] and [s]), in either [f]- or [s]-biased lexical contexts. In a subsequent categorization test, the former group of listeners identified more sounds on an [εf] - [εs] continuum as [f] than the latter group. In the present experiment, listeners received the same exposure and test stimuli, but did not make lexical decisions to the exposure items. Instead, they counted them. Categorization results were indistinguishable from those obtained earlier. These adjustments in fricative perception therefore do not depend on explicit judgments during exposure. This learning effect thus reflects automatic retuning of the interpretation of acoustic-phonetic information.

Abstract

The results of a word-spotting experiment are presented in which Dutch listeners tried to spot different types of bisyllabic Dutch words embedded in different types of nonsense contexts. Embedded verbs were not reliably harder to spot than embedded nouns; this suggests that nouns and verbs are recognised via the same basic processes. Iambic words were no harder to spot than trochaic words, suggesting that trochaic words are not in principle easier to recognise than iambic words. Words were harder to spot in consonantal contexts (i.e., contexts which themselves could not be words) than in longer contexts which contained at least one vowel (i.e., contexts which, though not words, were possible words of Dutch). A control experiment showed that this difference was not due to acoustic differences between the words in each context. The results support the claim that spoken-word recognition is sensitive to the viability of sound sequences as possible words.

Abstract

This paper presents lexical statistics on the pattern of occurrence of words embedded in other words. We report the results of an analysis of 25000 words, varying in length from two to six syllables, extracted from a phonetically-coded English dictionary (The Longman Dictionary of Contemporary English). Each syllable, and each string of syllables within each word was checked against the dictionary. Two analyses are presented: the first used a complete list of polysyllables, with look-up on the entire dictionary; the second used a sublist of content words, counting only embedded words which were themselves content words. The results have important implications for models of human speech recognition. The efficiency of these models depends, in different ways, on the number and location of words within words.

Abstract

This paper presents an analysis of semantic association norms for German nouns. In contrast to prior studies, we not only collected associations elicited by written representations of target objects but also by their pictorial representations. In a first analysis, we identified systematic differences in the type and distribution of associate responses for the two presentation forms. In a second analysis, we applied a soft cluster analysis to the collected target-response pairs. We subsequently used the clustering to predict noun ambiguity and to discriminate senses in our target nouns.

Abstract

Argues that the Seneca accent system can be explained more simply and naturally if the foot structure is reanalyzed as trochaic. Determination of the position of the accent by the position and structure of the accented syllable and by the position and structure of the post-tonic syllable; Assignment of the pair of syllables which interact to predict where accent is assigned in different iambic feet.

Abstract

The Revised Hierarchical Model (Kroll and Stewart, 1994) assumes that words in a bilingual’s languages have separate word form representations but shared conceptual representations. Two routes lead from an L2 word form to its conceptual representation: the word association route, where concepts are accessed through the corresponding L1 word form, and the concept mediation route, with direct access from L2 to concepts. To investigate word association, we presented proficient late German-Dutch bilinguals with L2 non-cognate word pairs in which the L1 translation of the first word rhymed with the second word (e.g. GRAP (joke) – Witz – FIETS (bike)). If the first word in a pair activated its L1 equivalent, then a phonological priming effect on the second word was expected. Priming was observed in lexical decision but not in semantic decision (living/non-living) on L2 words. In a control group of Dutch native speakers, no priming effect was found. This suggests that proficient bilinguals still make use of their L1 word form lexicon to process L2 in lexical decision.

Abstract

Phonological encoding in language production can be defined as a set of processes generating utterance forms on the basis of semantic and syntactic information. Most evidence about these processes stems from analyses of sound errors. In section 1 of this paper, certain important results of these analyses are reviewed. Two prominent models of phonological encoding, which are mainly based on speech error evidence, are discussed in section 2. In section 3, limitations of speech error analyses are discussed, and it is argued that detailed and comprehensive models of phonological encoding cannot be derived solely on the basis of error analyses. As is argued in section 4, a new research strategy is required. Instead of using the properties of errors to draw inferences about the generation of correct word forms, future research should directly investigate the normal process of phonological encoding.

Abstract

Tip-of-the-tongue states may represent the momentary unavailability of an otherwise accessible word or the weak activation of an otherwise inaccessible word. In three experiments designed to address these alternative views, subjects attempted to retrieve rare target words from their definitions. The definitions were followed by cues that were related to the targets in sound, by cues that were related in meaning, and by cues that were not related to the targets. Experiment 1 found that compared with unrelated cues, related cue words that were presented immediately after target definitions helped rather than hindered lexical retrieval, and that sound cues were more effective retrieval aids than meaning cues. Experiment 2 replicated these results when cues were presented after an initial target-retrieval attempt. These findings reverse a previous one (Jones, 1989) that was reproduced in Experiment 3 and shown to stem from a small group of unusually difficult target definitions.

Abstract

Eye movements have been shown to reflect word recognition and language comprehension processes occurring during reading and auditory language comprehension. The present study examines whether the eye movements speakers make during object naming similarly reflect speech planning processes. In Experiment 1, speakers named object pairs saying, for instance, 'scooter and hat'. The objects were presented as ordinary line drawings or with partly dele:ed contours and had high or low frequency names. Contour type and frequency both significantly affected the mean naming latencies and the mean time spent looking at the objects. The frequency effects disappeared in Experiment 2, in which the participants categorized the objects instead of naming them. This suggests that the frequency effects of Experiment 1 arose during lexical retrieval. We conclude that eye movements during object naming indeed reflect linguistic planning processes and that the speakers' decision to move their eyes from one object to the next is contingent upon the retrieval of the phonological form of the object names.

Abstract

The goal of speech perception is understanding a speaker's message. To achieve this, listeners must recognize the words that comprise a spoken utterance. This in turn implies distinguishing these words from other minimally different words (e.g., word from bird, etc.), and this involves making phonemic distinctions. The article summarizes research on the perception of phonemic distinctions, on how listeners cope with the continuity and variability of speech signals, and on how phonemic information is mapped onto the representations of words. Particular attention is paid to theories of speech perception and word recognition.

Abstract

This study examined whether compensation for coarticulation in fricative–vowel syllables is phonologically mediated or a consequence of auditory processes. Smits (2001a) had shown that compensation occurs for anticipatory lip rounding in a fricative caused by a following rounded vowel in Dutch. In a first experiment, the possibility that compensation is due to general auditory processing was investigated using nonspeech sounds. These did not cause context effects akin to compensation for coarticulation, although nonspeech sounds influenced speech sound identification in an integrative fashion. In a second experiment, a possible phonological basis for compensation for coarticulation was assessed by using audiovisual speech. Visual displays, which induced the perception of a rounded vowel, also influenced compensation for anticipatory lip rounding in the fricative. These results indicate that compensation for anticipatory lip rounding in fricative–vowel syllables is phonologically mediated. This result is discussed in the light of other compensation-for-coarticulation findings and general theories of speech perception.

Abstract

We investigated how spoken words are recognized when they have been altered by phonological assimilation. Previous research has shown that there is a process of perceptual compensation for phonological assimilations. Three recently formulated proposals regarding the mechanisms for compensation for assimilation make different predictions with regard to the level at which compensation is supposed to occur as well as regarding the role of specific language experience. In the present study, Hungarian words and nonwords, in which a viable and an unviable liquid assimilation was applied, were presented to Hungarian and Dutch listeners in an identification task and a discrimination task. Results indicate that viably changed forms are difficult to distinguish from canonical forms independent of experience with the assimilation rule applied in the utterances. This reveals that auditory processing contributes to perceptual compensation for assimilation, while language experience has only a minor role to play when identification is required.

Abstract

In a series of 5 experiments, we investigated whether the processing of phonologically assimilated utterances is influenced by language learning. Previous experiments had shown that phonological assimilations, such as /lean#bacon/→[leam bacon], are compensated for in perception. In this article, we investigated whether compensation for assimilation can occur without experience with an assimilation rule using automatic event-related potentials. Our first experiment indicated that Dutch listeners compensate for a Hungarian assimilation rule. Two subsequent experiments, however, failed to show compensation for assimilation by both Dutch and Hungarian listeners. Two additional experiments showed that this was due to the acoustic properties of the assimilated utterance, confirming earlier reports that phonetic detail is important in compensation for assimilation. Our data indicate that compensation for assimilation can occur without experience with an assimilation rule, in line with phonetic–phonological theories that assume that speech production is influenced by speech-perception abilities.

Abstract

Vowel normalization in speech perception was investigated in three experiments. The range of the second formant in a carrier phrase was manipulated and this affected the perception of a target vowel in a compensatory fashion: A low F2 range in the carrier phrase made it more likely that the target vowel was perceived as a front vowel, that is, with a high F2. Recent experiments indicated that this effect might be moderated by the lexical status of the constituents of the carrier phrase. Manipulation of the lexical status in the present experiments, however, did not affect vowel normalization. In contrast, the range of vowels in the carrier phrase did influence vowel normalization. If the carrier phrase consisted of mid-to-high front vowels only, vowel categories shifted only for mid-to-high front vowels. It is argued that these results are a challenge for episodic models of word recognition.

Abstract

In everyday speech, words may be reduced. Little is known about the consequences of such reductions for spoken word comprehension. This study investigated /t/-lenition in Dutch in two corpus studies and three perceptual experiments. The production studies revealed that /t/-lenition is most likely to occur after [s] and before bilabial consonants. The perception experiments showed that listeners take into account both phonological context, phonetic detail, and the lexical status of the form in the interpretation of codas that may or may not contain a lenited word-final /t/. These results speak against models of word recognition that make hard decisions on a prelexical level.

Abstract

In discourse, older adults tend to be more verbose and more disfluent than young adults, especially when the task is difficult and when it places few constraints on the content of the utterance. This may be due to (a) language-specific deficits in planning the content and syntactic structure of utterances or in selecting and retrieving words from the mental lexicon, (b) a general deficit in inhibiting irrelevant information, or (c) the selection of a specific speech style. The possibility that older adults have a deficit in lexical retrieval is supported by the results of picture naming studies, in which older adults have been found to name objects less accurately and more slowly than young adults, and by the results of definition naming studies, in which older adults have been found to experience more tip-of-the-tongue (TOT) states than young adults. The available evidence suggests that these age differences are largely due to weakening of the connections linking word lemmas to phonological word forms, though adults above 70 years of age may have an additional deficit in lemma selection.

Abstract

The present doctoral thesis investigates the temporal characteristics of the retrieval of semantic and syntactic word properties in language comprehension. In particular, an attempt is made to assess the retrieval order of semantic category and grammatical gender information, using the lateralized readiness potential and the inhibition-related N2 effect. Chapter 1 contains a general introduction. Chapter 2 reports an experiment that employs the two-choice go/nogo task in combination with EEG recordings to establish the retrieval order of semantic category and grammatical gender for written words presented in isolation. The results point to a time course where semantic information becomes available before syntactic information. Chapter 3 focuses on the retrieval of grammatical gender. In order to examine whether gender retrieval can be speeded up by context, nouns are presented in gender congruent and gender incongruent prime-target pairs and reaction times for gender decisions are measured. For stimulus onset asynchronies of 100 ms and 0 ms, gender congruent pairs show faster responses than incongruent ones, whereas there is no effect of gender congruity for a stimulus onset asynchrony of 300 ms. A simulation with a localist computational model that implements competition between gender representations (WEAVER; Roelofs, 1992) is able to capture these findings. In chapter 4, the gender congruency manipulation is transferred to another ERP experiment with the two-choice go/nogo task. As the time course of gender retrieval is altered through primes, the order relative to semantic category retrieval is assessed again. The results indicate that with gender congruent primes, grammatical gender becomes available before semantic category. Such a reversal of retrieval order, as compared to chapter 2, implies a parallel rather than a serial discrete arrangement of the retrieval processes, since the latter variant precludes changes in retrieval order. Finally, chapter 5 offers a summary and general discussion of the main findings.

Abstract

The recognition of a word makes available its semantic and
syntactic properties. Using electrophysiological recordings, we
investigated whether one set of these properties is available
earlier than the other set. Dutch participants saw nouns on a
computer screen and performed push-button responses: In
one task, grammatical gender determined response hand
(left/right) and semantic category determined response execution
(go/no-go). In the other task, response hand depended
on semantic category, whereas response execution depended
on gender. During the latter task, response preparation occurred
on no-go trials, as measured by the lateralized
readiness potential: Semantic information was used for
response preparation before gender information inhibited
this process. Furthermore, an inhibition-related N2 effect
occurred earlier for inhibition by semantics than for inhibition
by gender. In summary, electrophysiological measures
of both response preparation and inhibition indicated that
the semantic word property was available earlier than the
syntactic word property when participants read single
words.

Abstract

Muscular hypertrophy in callipyge sheep results from a single nucleotide substitution located in the genomic interval between the imprinted Delta, Drosophila, Homolog-like 1 (DLK1) and Maternally Expressed Gene 3 (MEG3). The mechanism linking the mutation to muscle hypertrophy is unclear but involves DLK1 overexpression. The mutation is contained within CLPG1 transcripts produced from this region. Herein we show that CLPG1 is expressed prenatally in the hypertrophy-responsive longissimus dorsi muscle by all four possible genotypes, but postnatal expression is restricted to sheep carrying the mutation. Surprisingly, the mutation results in nonimprinted monoallelic transcription of CLPG1 from only the mutated allele in adult sheep, whereas it is expressed biallelically during prenatal development. We further demonstrate that local CpG methylation is altered by the presence of the mutation in longissimus dorsi of postnatal sheep. For 10 CpG sites flanking the mutation, methylation is similar prenatally across genotypes, but doubles postnatally in normal sheep. This normal postnatal increase in methylation is significantly repressed in sheep carrying one copy of the mutation, and repressed even further in sheep with two mutant alleles. The attenuation in methylation status in the callipyge sheep correlates with the onset of the phenotype, continued CLPG1 transcription, and high-level expression of DLK1. In contrast, normal sheep exhibit hypermethylation of this locus after birth and CLPG1 silencing, which coincides with DLK1 transcriptional repression. These data are consistent with the notion that the callipyge mutation inhibits perinatal nucleation of regional chromatin condensation resulting in continued elevated transcription of prenatal DLK1 levels in adult callipyge sheep. We propose a model incorporating these results that can also account for the enigmatic normal phenotype of homozygous mutant sheep.

Abstract

Children are able to take multiple perspectives in talking about entities and events. But the nature of children's sensitivities to the complex patterns of perspective-taking in adult language is unknown. We examine perspective-taking in four- and six-year-old Tamil-speaking children describing placement events, as reflected in the use of a general placement verb (veyyii ‘put’) versus two fine-grained caused posture expressions specifying orientation, either vertical (nikka veyyii ‘make stand’) or horizontal (paDka veyyii ‘make lie’). We also explore whether animacy systematically promotes shifts to a fine-grained perspective. The results show that four- and six-year-olds switch perspectives as flexibly and systematically as adults do. Animacy influences shifts to a fine-grained perspective similarly across age groups. However, unexpectedly, six-year-olds also display greater overall sensitivity to orientation, preferring the vertical over the horizontal caused posture expression. Despite early flexibility, the factors governing the patterns of perspective-taking on events are undergoing change even in later childhood, reminiscent of U-shaped semantic reorganizations observed in children's lexical knowledge. The present study points to the intriguing possibility that mechanisms that operate at the level of semantics could also influence subtle patterns of lexical choice and perspective-shifts.

Abstract

Approximately 4% of English-speaking children are affected by specific language impairment (SLI), a disorder in the development of language skills despite adequate opportunity and normal intelligence. Several studies have indicated the importance of genetic factors in SLI; a positive family history confers an increased risk of development, and concordance in monozygotic twins consistently exceeds that in dizygotic twins. However, like many behavioral traits, SLI is assumed to be genetically complex, with several loci contributing to the overall risk. We have compiled 98 families drawn from epidemiological and clinical populations, all with probands whose standard language scores fall ⩾1.5 SD below the mean for their age. Systematic genomewide quantitative-trait–locus analysis of three language-related measures (i.e., the Clinical Evaluation of Language Fundamentals–Revised [CELF-R] receptive and expressive scales and the nonword repetition [NWR] test) yielded two regions, one on chromosome 16 and one on 19, that both had maximum LOD scores of 3.55. Simulations suggest that, of these two multipoint results, the NWR linkage to chromosome 16q is the most significant, with empirical P values reaching 10−5, under both Haseman-Elston (HE) analysis (LOD score 3.55; P=.00003) and variance-components (VC) analysis (LOD score 2.57; P=.00008). Single-point analyses provided further support for involvement of this locus, with three markers, under the peak of linkage, yielding LOD scores >1.9. The 19q locus was linked to the CELF-R expressive-language score and exceeds the threshold for suggestive linkage under all types of analysis performed—multipoint HE analysis (LOD score 3.55; empirical P=.00004) and VC (LOD score 2.84; empirical P=.00027) and single-point HE analysis (LOD score 2.49) and VC (LOD score 2.22). Furthermore, both the clinical and epidemiological samples showed independent evidence of linkage on both chromosome 16q and chromosome 19q, indicating that these may represent universally important loci in SLI and, thus, general risk factors for language impairment.

Abstract

The FOXP2 gene, located on human 7q31 (at the SPCH1 locus), encodes a transcription factor containing a polyglutamine tract and a forkhead domain. FOXP2 is mutated in a severe monogenic form of speech and language impairment, segregating within a single large pedigree, and is also disrupted by a translocation in an isolated case. Several studies of autistic disorder have demonstrated linkage to a similar region of 7q (the AUTS1 locus), leading to the proposal that a single genetic factor on 7q31 contributes to both autism and language disorders. In the present study, we directly evaluate the impact of the FOXP2 gene with regard to both complex language impairments and autism, through use of association and mutation screening analyses. We conclude that coding-region variants in FOXP2 do not underlie the AUTS1 linkage and that the gene is unlikely to play a role in autism or more common forms of language impairment.

Abstract

In linguistic theories of how sentences encode meaning, a distinction is often made between the context-free rule-based combination of lexical–semantic features of the words within a sentence (‘‘semantics’’), and the contributions made by wider context (‘‘pragmatics’’). In psycholinguistics, this distinction has led to the view that listeners initially compute a local, context-independent meaning of a phrase or sentence before relating it to the wider context. An important aspect of such a two-step perspective on interpretation is that local semantics cannot initially be overruled by global contextual factors. In two spoken-language event-related potential experiments, we tested the viability of this claim by examining whether discourse context can overrule the impact of the core lexical–semantic feature animacy, considered to be an innate organizing principle of cognition. Two-step models of interpretation predict that verb–object animacy violations, as in ‘‘The girl comforted the clock,’’ will always perturb the unfolding interpretation process, regardless of wider context. When presented in isolation, such anomalies indeed elicit a clear N400 effect, a sign of interpretive problems. However, when the anomalies were embedded in a supportive context (e.g., a girl talking to a clock about his depression), this N400 effect disappeared completely. Moreover, given a suitable discourse context (e.g., a story about an amorous peanut), animacyviolating predicates (‘‘the peanut was in love’’) were actually processed more easily than canonical predicates (‘‘the peanut was salted’’). Our findings reveal that discourse context can immediately overrule local lexical–semantic violations, and therefore suggest that language comprehension does not involve an initially context-free semantic analysis.

Abstract

Although we usually have no trouble finding the right antecedent for a pronoun, the co-reference relations between pronouns and antecedents in everyday language are often ‘formally’ ambiguous. But a pronoun is only really ambiguous if a reader or listener indeed perceives it to be ambiguous. Whether this is the case may depend on at least two factors: the language processing skills of an individual reader, and the contextual bias towards one particular referential interpretation. In the current study, we used event related brain potentials (ERPs) to explore how both these factors affect the resolution of referentially ambiguous pronouns. We compared ERPs elicited by formally ambiguous and non-ambiguous pronouns that were embedded in simple sentences (e.g., “Jennifer Lopez told Madonna that she had too much money.”). Individual differences in language processing skills were assessed with the Reading Span task, while the contextual bias of each sentence (up to the critical pronoun) had been assessed in a referential cloze pretest. In line with earlier research, ambiguous pronouns elicited a sustained, frontal negative shift relative to non-ambiguous pronouns at the group-level. The size of this effect was correlated with Reading Span score, as well as with contextual bias. These results suggest that whether a reader perceives a formally ambiguous pronoun to be ambiguous is subtly co-determined by both individual language processing skills and contextual bias.

Abstract

The human language processor is conceived as a system that consists of several interrelated subsystems. Each subsystem performs a specific task in the complex process of language comprehension and production. A subsystem receives a particular input, performs certain specific operations on this input and yields a particular output. The subsystems can be characterized in terms of the transformations that relate the input representations to the output representations. An important issue in describing the language processing system is to identify the subsystems and to specify the relations between the subsystems. These relations can be conceived in two different ways. In one conception the subsystems are autonomous. They are related to each other only by the input-output channels. The operations in one subsystem are not affected by another system. The subsystems are modular, that is they are independent. In the other conception, the different subsystems influence each other. A subsystem affects the processes in another subsystem. In this conception there is an interaction between the subsystems.

Abstract

The reading process depends both on the text and on the reader. When we read a text, propositions in the current input are matched to propositions in the memory representation of the previous discourse but also to knowledge structures in long‐term memory. Therefore, memory‐based text processing refers both to the bottom‐up processing of the text and to the top‐down activation of the reader's knowledge. In this article, we focus on the role of cognitive structures in the reader's knowledge. We argue that causality is an important category in structuring human knowledge and that this property has consequences for text processing. Some research is discussed that illustrates that the more the information in the text reflects causal categories, the more easily the information is processed.

Abstract

We propose that speech comprehension involves the activation of token representations of the phonological forms of current lexical hypotheses, separately from the ongoing construction of a conceptual interpretation of the current utterance. In a series of cross-modal priming experiments, facilitation of lexical decision responses to visual target words (e.g., time) was found for targets that were semantic associates of auditory prime words (e.g., date) when the primes were isolated words, but not when the same primes appeared in sentence contexts. Identity priming (e.g., faster lexical decisions to visual date after spoken date than after an unrelated prime) appeared, however, both with isolated primes and with primes in prosodically neutral sentences. Associative priming in sentence contexts only emerged when sentence prosody involved contrastive accents, or when sentences were terminated immediately after the prime. Associative priming is therefore not an automatic consequence of speech processing. In no experiment was there associative priming from embedded words (e.g., sedate-time), but there was inhibitory identity priming (e.g., sedate-date) from embedded primes in sentence contexts. Speech comprehension therefore appears to involve separate distinct activation both of token phonological word representations and of conceptual word representations. Furthermore, both of these types of representation are distinct from the long-term memory representations of word form and meaning.

Abstract

In four experiments, we examined the facilitation that occurs when spoken-word targets rhyme with preceding spoken primes. In Experiment 1, listeners’ lexical decisions were faster to words following rhyming words (e.g., ramp–LAMP) than to words following unrelated primes (e.g., pink–LAMP). No facilitation was observed for nonword targets. Targets that almost rhymed with their primes (foils; e.g., bulk–SULSH) were included in Experiment 2; facilitation for rhyming targets was severely attenuated. Experiments 3 and 4 were single-word shadowing variants of the earlier experiments. There was facilitation for both rhyming words and nonwords; the presence of foils had no significant influence on the priming effect. A major component of the facilitation in lexical decision appears to be strategic: Listeners are biased to say “yes” to targets that rhyme with their primes, unless foils discourage this strategy. The nonstrategic component of phonological facilitation may reflect speech perception processes that operate prior to lexical access.

Abstract

Participants made visual lexical decisions to upper-case words and nonwords, and then categorized an ambiguous N–H letter continuum. The lexical decision phase included different exposure conditions: Some participants saw an ambiguous letter “?”, midway between N and H, in N-biased lexical contexts (e.g., REIG?), plus words with unambiguousH(e.g., WEIGH); others saw the reverse (e.g., WEIG?, REIGN). The first group categorized more of the test continuum as N than did the second group. Control groups, who saw “?” in nonword contexts (e.g., SMIG?), plus either of the unambiguous word sets (e.g., WEIGH or REIGN), showed no such subsequent effects. Perceptual learning about ambiguous letters therefore appears to be based on lexical knowledge, just as in an analogous speech experiment (Norris, McQueen, & Cutler, 2003) which showed similar lexical influence in learning about ambiguous phonemes. We argue that lexically guided learning is an efficient general strategy available for exploitation by different specific perceptual tasks.

Abstract

We report two experiments in which vowels and steady-state consonants served as targets in a speeded detection task. In the first experiment, two vowels were compared with one voiced and once unvoiced fricative. Response times (RTs) to the vowels were longer than to the fricatives. The error rate was higher for the consonants. Consonants in word-final position produced the shortest RTs, For the vowels, RT correlated negatively with target duration. In the second experiment, the same two vowel targets were compared with two nasals. This time there was no significant difference in RTs, but the error rate was still significantly higher for the consonants. Error rate and length correlated negatively for the vowels only. We conclude that RT differences between phonemes are independent of vocalic or consonantal status. Instead, we argue that the process of phoneme detection reflects more finely grained differences in acoustic/articulatory structure within the phonemic repertoire.

Abstract

There is much evidence for the existence of multiple memory systems. However, it has been argued that tasks assumed to reflect different memory systems share basic processing components and are mediated by overlapping neural systems. Here we used multivariate analysis of PET-data to analyze similarities and differences in brain activity for multiple tests of working memory, semantic memory, and episodic memory. The results from two experiments revealed between-systems differences, but also between-systems similarities and within-system differences. Specifically, support was obtained for a task-general working-memory network that may underlie active maintenance. Premotor and parietal regions were salient components of this network. A common network was also identified for two episodic tasks, cued recall and recognition, but not for a test of autobiographical memory. This network involved regions in right inferior and polar frontal cortex, and lateral and medial parietal cortex. Several of these regions were also engaged during the working-memory tasks, indicating shared processing for episodic and working memory. Fact retrieval and synonym generation were associated with increased activity in left inferior frontal and middle temporal regions and right cerebellum. This network was also associated with the autobiographical task, but not with living/non-living classification, and may reflect elaborate retrieval of semantic information. Implications of the present results for the classification of memory tasks with respect to systems and/or processes are discussed.

Abstract

Memorializes Martin D. S. Braine, whose research on child language acquisition and on both child and adult thinking and reasoning had a major influence on modern cognitive psychology. Addressing meaning as well as position, Braine argued that children start acquiring language by learning narrow-scope positional formulas that map components of meaning to positions in the utterance. These proposals were critical in starting discussions of the possible universality of the pivot-grammar stage and of the role of syntax, semantics,and pragmatics in children's early grammar and were pivotal to the rise of approaches in which cognitive development in language acquisition is stressed.

Abstract

This dissertation documents the emergence of a new language, Light Warlpiri, in the multilingual community of Lajamanu in northern Australia. It then examines the acquisition of Light Warlpiri language, and of the heritage language, Lajamanu Warlpiri, by children. Light Warlpiri has arisen from contact between Lajamanu Warlpiri (a Pama-Nyungan language), Kriol (an English-based creole), and varieties of English. It is a Mixed Language, meaning that none of its source languages can be considered to be the sole parent language. Most verbs and the verbal morphology are from Aboriginal English or Kriol, while most nouns and the nominal morphology are from Warlpiri. The language input to children is complex. Adults older than about thirty speak Lajamanu Warlpiri and code-switch into Aboriginal English or Kriol. Younger adults, the parents of the current cohort of children, speak Light Warlpiri and code-switch into Lajamanu Warlpiri and into Aboriginal English or Kriol. Lajamanu Warlpiri and Light Warlpiri, the two main input languages to children, both indicate A arguments with ergative case-marking (and they share one allomorph of the marker), but Lajamanu Warlpiri includes the marker much more consistently than Light Warlpiri. Word order is variable in both languages. Children learn both languages from birth, but they target Light Warlpiri as the language of their everyday interactions, and they speak it almost exclusively until four to six years of age. Adults and children show similar patterns of ergative marking and word order in Light Warlpiri. But differences between age groups are found in ergative marking in Lajamanu Warlpiri - for the oldest group of adults, ergative marking is obligatory, but for younger adults and children, it is not. Determining when children differentiate between two input languages has been a major goal in the study of bilingual acquisition. The two languages in this study share lexical and grammatical properties, making distinctions between them quite subtle. Both adults and children distribute ergative marking differently in the two languages, but show similar word order patterns in both. However the children show a stronger correlation between ergative marking and word order patterns than do the adults, suggesting that they are spearheading processes of language change. In their comprehension of sentences in both Lajamanu Warlpiri and Light Warlpiri, adults use a case-marking strategy to identify the A argument (i.e. N+erg = A argument, N-erg = O argument). The children are not adult-like in using this strategy at age 5, when they also used a word order strategy, but they gradually move towards being adult-like with increased age.

Abstract

Do speakers use spontaneous gestures accompanying their speech for themselves or to communicate their message to their addressees? Two experiments show that speakers change the orientation of their gestures depending on the location of shared space, that is, the intersection of the gesture spaces of the speakers and addressees. Gesture orientations change more frequently when they accompany spatial prepositions such as into and out, which describe motion that has a beginning and end point, rather than across, which depicts an unbounded path across space. Speakers change their gestures so that they represent the beginning and end point of motion INTO or OUT by moving into or out of the shared space. Thus, speakers design their gestures for their addressees and therefore use them to communicate. This has implications for the view that gestures are a part of language use as well as for the role of gestures in speech production.

Abstract

In this paper we try to contribute to the body of knowledge about the acquisition of English epistemic modal verbs (e.g. Mary may/has to be at school). Semantically, these verbs encode possibility or necessity with respect to available evidence. Pragmatically, the use of epistemic modals often gives rise to scalar conversational inferences (Mary may be at school -> Mary doesn’t have to be at school). The acquisition of epistemic modals is challenging for children on both these levels. In this paper, we present findings from two studies which were conducted with 5-year-old children and adults. Our findings, unlike previous work, show that 5-yr-olds have mastered epistemic modal semantics, including the notions of necessity and possibility. However, they are still in the process of acquiring epistemic modal pragmatics.

Abstract

Dyslexia is one of the most prevalent childhood cognitive disorders, affecting approximately 5% of school-age children. We have recently identified a risk haplotype associated with dyslexia on chromosome 6p22.2 which spans the TTRAP gene and portions of THEM2 and KIAA0319. Here we show that in the presence of the risk haplotype, the expression of the KIAA0319 gene is reduced but the expression of the other two genes remains unaffected. Using in situ hybridization, we detect a very distinct expression pattern of the KIAA0319 gene in the developing cerebral neocortex of mouse and human fetuses. Moreover, interference with rat Kiaa0319 expression in utero leads to impaired neuronal migration in the developing cerebral neocortex. These data suggest a direct link between a specific genetic background and a biological mechanism leading to the development of dyslexia: the risk haplotype on chromosome 6p22.2 down-regulates the KIAA0319 gene which is required for neuronal migration during the formation of the cerebral neocortex.

Abstract

The relationship between synchronous neuronal activity as measured with EEG and the blood oxygenation level dependent (BOLD) signal as measured during fMRI is not clear. This work investigates the relationship by combining EEG and fMRI measures of the strong increase in beta frequency power following movement, the so-called post-movement beta rebound (PMBR). The time course of the PMBR, as measured by EEG, was included as a regressor in the fMRI analysis, allowing identification of a region of associated BOLD signal increase in the sensorimotor cortex, with the most significant region in the post-central sulcus. The increase in the BOLD signal suggests that the number of active neurons and/or their synaptic rate is increased during the PMBR. The duration of the BOLD response curve in the PMBR region is significantly longer than in the activated motor region, and is well fitted by a model including both motor and PMBR regressors. An intersubject correlation between the BOLD signal amplitude associated with the PMBR regressor and the PMBR strength as measured with EEG provides further evidence that this region is a source of the PMBR. There is a strong intra-subject correlation between the BOLD signal amplitude in the sensorimotor cortex during movement and the PMBR strength as measured by EEG, suggesting either that the motor activity itself, or somatosensory inputs associated with the motor activity, influence the PMBR. This work provides further evidence for a BOLD signal change associated with changes in neuronal synchrony, so opening up the possibility of studying other event-related oscillatory changes using fMRI.

Abstract

In this paper we follow two beginning learners of English, Andrea and Santo, over a period of 2 years as they develop means to structure the declarative utterances they produce in various production tasks, and then we look at the following problem: In the early stages of acquisition, both learners develop a common learner variety; during these stages, we see a picture of two learner varieties developing similar regularities determined by the minimal requirements of the tasks we examine. Andrea subsequently develops further morphosyntactic means to achieve greater cohesion in his discourse. But Santo does not. Although we can identify contexts where the grammaticalization of Andrea's production allows him to go beyond the initial constraints of his variety, it is much more difficult to ascertain why Santo, faced with the same constraints in the same contexts, does not follow this path. Some lines of investigation into this problem are then suggested.

Abstract

En este artículo se desarrolla un método automático de segmentación de fonemas no supervisado. Este método utiliza el algoritmo de agrupación de máximo margen [1] para realizar segmentación de fonemas sobre habla continua sin necesidad de información a priori para el entrenamiento del sistema.

Abstract

Literacy and education represent essential aspects of contemporary society and subserve important aspects of socialization and cultural transmission. The study of illiterate subjects represents one approach to investigate the interactions between neurobiological and cultural factors in cognitive development, individual learning, and their influence on the functional organization of the brain. In this chapter we review some recent cognitive, neuroanatomic, and functional neuroimaging results indicating that formal education influences important aspects of the human brain. Taken together this provides strong support for the idea that the brain is modulated by literacy and formal education, which in turn change the brains capacity to interact with its environment, including the individual's contemporary culture. In other words, the individual is able to participate in, interact with, and actively contribute to the process of cultural transmission in new ways through acquired cognitive skills.

Abstract

The irrelevant speech effect illustrates that sounds that are irrelevant to a visually presented short-term memory task still interfere with neuronal function. In the present study we explore the functional and effective connectivity of such interference. The functional connectivity analysis suggested an interaction between the level of irrelevant speech and the correlation between in particular the left superior temporal region, associated with verbal working memory, and the left medial temporal lobe. Based on this psycho-physiological interaction, and to broaden the understanding of this result, we performed a network analysis, using a simple network model for verbal working memory, to analyze its interaction with the medial temporal lobe memory system. The results showed dissociations in terms of network interactions between frontal as well as parietal and temporal areas in relation to the medial temporal lobe. The results of the present study suggest that a transition from phonological loop processing towards an engagement of episodic processing might take place during the processing of interfering irrelevant sounds. We speculate that, in response to the irrelevant sounds, this reflects a dynamic shift in processing as suggested by a closer interaction between a verbal working memory system and the medial temporal lobe memory system.

Abstract

It has been suggested that placebo analgesia involves both higher order cognitive networks and endogenous opioid systems. The rostral anterior cingulate cortex (rACC) and the brainstem are implicated in opioid analgesia, suggesting a similar role for these structures in placebo analgesia. Using positron emission tomography, we confirmed that both opioid and placebo analgesia are associated with increased activity in the rACC. We also observed a covariation between the activity in the rACC and the brainstem during both opioid and placebo analgesia, but not during the pain-only condition. These findings indicate a related neural mechanism in placebo and opioid analgesia.

Abstract

It has been suggested that placebo analgesia involves both higher order cognitive networks and endogenous opioid systems. The rostral anterior cingulate cortex (rACC) and the brainstem are implicated in opioid analgesia, suggesting a similar role for these structures in placebo analgesia. Using positron emission tomography, we confirmed that both opioid and placebo analgesia are associated with increased activity in the rACC. We also observed a covariation between the activity in the rACC and the brainstem during both opioid and placebo analgesia, but not during the pain-only condition. These findings indicate a related neural mechanism in placebo and opioid analgesia.

Abstract

Several functional imaging studies of pain, using a number of different experimental paradigms and a variety of reference states, have failed to detect activations in the somatosensory cortices, while other imaging studies of pain have reported significant activations in these regions. The role of the somatosensory areas in pain processing has therefore been debated. In the present study the left hand was immersed in painfully cold water (standard cold pressor test) and in nonpainfully cold water during 2 min, and PET-scans were obtained either during the first or the second minute of stimulation. We observed no significant increase of activity in the somatosensory regions when the painful conditions were directly compared with the control conditions. In order to better understand the role of the primary somatosensory cortex (S1) in pain processing we used a regression analysis to study the relation between a ROI (region of interest) in the somatotopic S1-area for the stimulated hand and other regions known to be involved in pain processing. We hypothesized that although no increased activity was observed in the S1 during pain, this region would change its covariation pattern during noxious input as compared to the control stimulation if it is involved in or affected by the processing of pain. In the nonpainful cold conditions widespread regions of the ipsilateral and contralateral somatosensory cortex showed a positive covariation with the activity in the S1-ROI. However, during the first and second minute of pain this regression was significantly attenuated. During the second minute of painful stimulation there was a significant positive covariation between the activity in the S1-ROI and the other regions that are known to be involved in pain processing. Importantly, this relation was significantly stronger for the insula and the orbitofrontal cortex bilaterally when compared to the nonpainful state. The results indicate that the S1-cortex may be engaged in or affected by the processing of pain although no differential activity is observed when pain is compared with the reference condition.

Abstract

Doubts have been cast on the strict dissociation between short- and long-term memory systems. Specifically, several neuroimaging studies have shown that the medial temporal lobe, a region almost invariably associated with long-term memory, is involved in active short-term memory maintenance. Furthermore, a recent study in hippocampally lesioned patients has shown that the hippocampus is critically involved in associating objects and their locations, even when the delay period lasts only 8 s. However, the critical feature that causes the medial temporal lobe, and in particular the hippocampus, to participate in active maintenance is still unknown. This study was designed in order to explore hippocampal involvement in active maintenance of spatial and non-spatial associations. Eighteen participants performed a delayed-match-to-sample task in which they had to maintain either object–location associations, color–number association, single colors, or single locations. Whole-brain activity was measured using event-related functional magnetic resonance imaging and analyzed using a random effects model. Right lateralized hippocampal activity was evident when participants had to maintain object–location associations, but not when they had to maintain object–color associations or single items. The present results suggest a hippocampal involvement in active maintenance when feature combinations that include spatial information have to be maintained online.

Abstract

In this study data from the first six months of 12 children s multiword speech were used to test the validity of Valian's (1991) syntactic perfor-mance-limitation account and Tomasello s (1992) verb-island account of early multiword speech with particular reference to the development of the English verb category. The results provide evidence for appropriate use of verb morphology, auxiliary verb structures, pronoun case marking, and SVO word order from quite early in development. However, they also demonstrate a great deal of lexical specificity in the children's use of these systems, evidenced by a lack of overlap in the verbs to which different morphological markers were applied, a lack of overlap in the verbs with which different auxiliary verbs were used, a disproportionate use of the first person singular nominative pronoun I, and a lack of overlap in the lexical items that served as the subjects and direct objects of transitive verbs. These findings raise problems for both a syntactic performance-limitation account and a strong verb-island account of the data and suggest the need to develop a more general lexiealist account of early multiword speech that explains why some words come to function as "islands" of organization in the child's grammar and others do not.

Abstract

This study investigates whether the acoustic durations of derivational affixes in Dutch are affected by the frequency of the word they occur in. In a word naming experiment, subjects were presented with a large number of words containing one of the affixes ge-, ver-, ont, or -lijk. Their responses were recorded on DAT tapes, and the durations of the affixes were measured using Automatic Speech Recognition technology. To investigate whether frequency also affected durations when speech rate was high, the presentation rate of the stimuli was varied. The results show that a higher frequency of the word as a whole led to shorter acoustic realizations for all affixes. Furthermore, affixes became shorter as the presentation rate of the stimuli increased. There was no interaction between word frequency and presentation rate, suggesting that the frequency effect also applies in situations in which the speed of articulation is very high.

Abstract

When assessing dangerousness of mentally ill persons with the objective of making a decision on civil commitment, medical and legal experts use information typically belonging to their professional frame of reference. This is investigated in two studies of the commitment decision. It is hypothesized that an ‘expertise bias’ may explain differences between the medical and the legal expert in defining the dangerousness concept (study 1), and in assessing the seriousness of the danger (study 2). Judges define dangerousness more often as harming others, whereas psychiatrists more often include harm to self in the definition. In assessing the seriousness of the danger, experts tend to be more tolerant with regard to false negatives, as the type of behavior is more familiar to them. The theoretical and practical implications of the results are discussed.

Abstract

Participants performed an artificial grammar learning task, in which the standard finite
state grammar (J. Verb. Learn. Verb. Behavior 6 (1967) 855) was extended with a recursive
rule generating self-embedded sequences. We studied the learnability of such a rule in two experiments.
The results verify the general hypothesis that recursivity can be learned in an artificial
grammar learning task. However this learning seems to be rather based on recognising
chunks than on abstract rule induction. First, performance was better for strings with more
than one level of self-embedding in the sequence, uncovering more clearly the self-embedding
pattern. Second, the infinite repeatability of the recursive rule application was not spontaneously
induced from the training, but it was when an additional cue about this possibility was
given. Finally, participants were able to verbalise their knowledge of the fragments making up
the sequences––especially in the crucial front and back positions––, whereas knowledge of the
underlying structure, to the extent it was acquired, was not articulatable. The results are discussed
in relation to previous studies on the implicit learnability of complex and abstract rules.

Abstract

Greek is a language with lexical stress that marks stress orthographically with a special diacritic. Thus, the orthography and the lexicon constitute potential sources of stress assignment information in addition to any possible general default metrical pattern. Here, we report two experiments with secondary education children reading aloud pseudo-word stimuli, in which we manipulated the availability of lexical (using stimuli resembling particular words) and visual (existence and placement of the diacritic) information. The reliance on the diacritic was found to be imperfect. Strong lexical effects as well as a default metrical pattern stressing the penultimate syllable were revealed. Reading models must be extended to account for multisyllabic word reading including, in particular, stress assignment based on the interplay among multiple possible sources of information.