Neural basis of lexical-semantic processing and integration of symbolic gestures with words

Three studies investigated the relation between symbolic gestures and words, aiming at discover the neural basis and behavioural features of the lexical semantic processing and integration of the two communicative signals. The first study aimed at determining whether elaboration of communicative signals (symbolic gestures and words) is always accompanied by integration with each other and, if present, this integration can be considered in support of the existence of a same control mechanism. Experiment 1 aimed at determining whether and how gesture is integrated with word. Participants were administered with a semantic priming paradigm with a lexical decision task and pronounced a target word, which was preceded by a meaningful or meaningless prime gesture. When meaningful, the gesture could be either congruent or incongruent with word meaning. Duration of prime presentation (100, 250, 400 ms) randomly varied. Voice spectra, lip kinematics, and time to response were recorded and analyzed. Formant 1 of voice spectra, and mean velocity in lip kinematics increased when the prime was meaningful and congruent with the word, as compared to meaningless gesture. In other words, parameters of voice and movement were magnified by congruence, but this occurred only when prime duration was 250 ms. Time to response to meaningful gesture was shorter in the condition of congruence compared to incongruence. Experiment 2 aimed at determining whether the mechanism of integration of a prime word with a target word is similar to that of a prime gesture with a target word. Formant 1 of the target word increased when word prime was meaningful and congruent, as compared to meaningless congruent prime. Increase was, however, present for whatever prime word duration. In the second study, experiment 3 aimed at determining whether symbolic prime gesture comprehension makes use of motor simulation. Transcranial Magnetic Stimulation was delivered to left primary motor cortex 100, 250, 500 ms after prime gesture presentation. Motor Evoked Potential of First Dorsal Interosseus increased when stimulation occurred 100 ms post-stimulus. Thus, gesture was understood within 100ms and integrated with the target word within 250 ms. Experiment 4 excluded any hand motor simulation in order to comprehend prime word. The effect of the prior presentation of a symbolic gesture on congruent target word processing was investigated in study 3. In experiment 5, symbolic gestures were presented as primes, followed by semantically congruent target word or pseudowords. In this case, lexical-semantic decision was accompanied by a motor simulation at 100ms after the onset of the verbal stimuli. Summing up, the same type of integration with a word was present for both prime gesture and word. It was probably subsequent to understanding of the signal, which used motor simulation for gesture and direct access to semantics for words. However, gesture and words could be understood at the same motor level through simulation if words were preceded by an adequate gestural context. Results are discussed in the prospective of a continuum between transitive actions and emblems, in parallelism with language; the grounded/symbolic content of the different signals evidences relation between sensorimotor and linguistic systems, which could interact at different levels.

The influence of intention on masked priming: A study with semantic classification of words

Unconscious perception is commonly described as a phenomenon that is not under intentional control and relies on automatic processes. We challenge this view by arguing that some automatic processes may indeed be under intentional control, which is implemented in task-sets that define how the task is to be performed. In consequence, those prime attributes that are relevant to the task will be most effective. To investigate this hypothesis, we used a paradigm which has been shown to yield reliable short-lived priming in tasks based on semantic classification of words. This type of study uses fast, well practised classification responses, whereby responses to targets are much less accurate if prime and target belong to a different category than if they belong to the same category. In three experiments, we investigated whether the intention to classify the same words with respect to different semantic categories had a differential effect on priming. The results suggest that this was indeed the case: Priming varied with the task in all experiments. However, although participants reported not seeing the primes, they were able to classify the primes better than chance using the classification task they had used before with the targets. When a lexical task was used for discrimination in experiment 4, masked primes could however not be discriminated. Also, priming was as pronounced when the primes were visible as when they were invisible. The pattern of results suggests that participants had intentional control on prime processing, even if they reported not seeing the primes.

Changes in cortical and sub-cortical patterns of activity associated with aging during the performance of a lexical set-shifting task

Bien que le passage du temps altère le cerveau, la cognition ne suit pas nécessairement le même destin. En effet, il existe des mécanismes compensatoires qui permettent de préserver la cognition (réserve cognitive) malgré le vieillissement. Les personnes âgées peuvent utiliser de nouveaux circuits neuronaux (compensation neuronale) ou des circuits existants moins susceptibles aux effets du vieillissement (réserve neuronale) pour maintenir un haut niveau de performance cognitive. Toutefois, la façon dont ces mécanismes affectent l’activité corticale et striatale lors de tâches impliquant des changements de règles (set-shifting) et durant le traitement sémantique et phonologique n’a pas été extensivement explorée. Le but de cette thèse est d’explorer comment le vieillissement affecte les patrons d’activité cérébrale dans les processus exécutifs d’une part et dans l’utilisation de règles lexicales d’autre part. Pour cela nous avons utilisé l’imagerie par résonance magnétique fonctionnelle (IRMf) lors de la performance d’une tâche lexicale analogue à celle du Wisconsin. Cette tâche a été fortement liée à de l’activité fronto-stritale lors des changements de règles, ainsi qu’à la mobilisation de régions associées au traitement sémantique et phonologique lors de décisions sémantiques et phonologiques, respectivement. Par conséquent, nous avons comparé l’activité cérébrale de jeunes individus (18 à 35 ans) à celle d’individus âgés (55 à 75 ans) lors de l’exécution de cette tâche. Les deux groupes ont montré l’implication de boucles fronto-striatales associées à la planification et à l’exécution de changements de règle. Toutefois, alors que les jeunes semblaient activer une « boucle cognitive » (cortex préfrontal ventrolatéral, noyau caudé et thalamus) lorsqu’ils se voyaient indiquer qu’un changement de règle était requis, et une « boucle motrice » (cortex postérieur préfrontal et putamen) lorsqu’ils devaient effectuer le changement, les participants âgés montraient une activation des deux boucles lors de l’exécution des changements de règle seulement. Les jeunes adultes tendaient à présenter une augmentation de l’activité du cortex préfrontal ventrolatéral, du gyrus fusiforme, du lobe ventral temporale et du noyau caudé lors des décisions sémantiques, ainsi que de l’activité au niveau de l’aire de Broca postérieur, de la junction temporopariétale et du cortex moteur lors de décisions phonologiques. Les participants âgés ont montré de l’activité au niveau du cortex préfrontal latéral et moteur durant les deux types de décisions lexicales. De plus, lorsque les décisions sémantiques et phonologiques ont été comparées entre elles, les jeunes ont montré des différences significatives au niveau de plusieurs régions cérébrales, mais pas les âgés. En conclusion, notre première étude a montré, lors du set-shifting, un délai de l’activité cérébrale chez les personnes âgées. Cela nous a permis de conceptualiser l’Hypothèse Temporelle de Compensation (troisième manuscrit) qui consiste en l’existence d’un mécanisme compensatoire caractérisé par un délai d’activité cérébrale lié au vieillissement permettant de préserver la cognition au détriment de la vitesse d’exécution. En ce qui concerne les processus langagiers (deuxième étude), les circuits sémantiques et phonologiques semblent se fusionner dans un seul circuit chez les individus âgés, cela représente vraisemblablement des mécanismes de réserve et de compensation neuronales qui permettent de préserver les habilités langagières.

Native speakers and task performance: comparing effects on complexity, fluency, and lexical diversity

This article argues that a native-speaker baseline is a neglected dimension of studies into second language (L2) performance. If we investigate how learners perform language tasks, we should distinguish what performance features are due to their processing an L2 and which are due to their performing a particular task. Having defined what we mean by “native speaker,” we present the background to a research study into task features on nonnative task performance, designed to include native-speaker data as a baseline for interpreting nonnative-speaker performance. The nonnative results, published in this journal (Tavakoli & Foster, 2008) are recapitulated and then the native-speaker results are presented and discussed in the light of them. The study is guided by the assumption that limited attentional resources impact on L2 performance and explores how narrative design features—namely complexity of storyline and tightness of narrative structure— affect complexity, fluency, accuracy, and lexical diversity in language. The results show that both native and nonnative speakers are prompted by storyline complexity to use more subordinated language, but narrative structure had different effects on native and nonnative fluency. The learners, who were based in either London or Tehran, did not differ in their performance when compared to each other, except in lexical diversity, where the learners in London were close to native-speaker levels. The implications of the results for the applicability of Levelt’s model of speaking to an L2 are discussed, as is the potential for further L2 research using native speakers as a baseline.

Assessing multilingual lexical incorporation hypotheses through a primed picture-naming task

The incorporation of new representations into the mental lexicon has raised numerous questions about the organisational principles that govern the process. A number of studies have argued that similarity between the new L3 items and existing representations in the L1 and L2 is the main incorporating force (Hall & Ecke, 2003; Herwig, 2001). Experimental evidence obtained through a primed picture-naming task with L1 Polish-L2 English learners of L3 Russian supports Hall and Ecke’s Parasitic Model of L3 vocabulary acquisition, displaying a significant main effect for both priming and proficiency. These results complement current models of vocabulary acquisition and lexical access in multilingual speakers.

What were they thinking? An exploration of child sexual offenders' beliefs using a lexical decision task

Cognitive distortions have been afforded a key role in the offending behaviour of child sexual offenders. While the mechanisms underlying cognitive distortions are not fully understood, they are generally thought to reflect entrenched beliefs that distinguish child sexual offenders from other individuals. We investigated this hypothesis using a robust experimental technique called the lexical decision task. Child sexual offenders, offender controls, and non-offender controls completed a lexical decision task in which they responded to words that completed sentences in either an offence-supportive or nonoffence-supportive manner. Contrary to predictions, child sexual offenders did not respond faster to words that were consistent with offence-supportive beliefs, relative to controls. However, they did show accelerated recognition for word stems supporting external locus of control beliefs. These results highlight the need to use cognitive experimental methods to study child sexual offenders' beliefs, and the importance of investigating potential alternative drivers of cognitive distortions.

The time-course of lexical activation in Japanese morphographic word recognition: Evidence for a character-driven processing model

This lexical decision study with eye tracking of Japanese two-kanji-character words investigated the order in which a whole two-character word and its morphographic constituents are activated in the course of lexical access, the relative contributions of the left and the right characters in lexical decision, the depth to which semantic radicals are processed, and how nonlinguistic factors affect lexical processes. Mixed-effects regression analyses of response times and subgaze durations (i.e., first-pass fixation time spent on each of the two characters) revealed joint contributions of morphographic units at all levels of the linguistic structure with the magnitude and the direction of the lexical effects modulated by readers’ locus of attention in a left-to-right preferred processing path. During the early time frame, character effects were larger in magnitude and more robust than radical and whole-word effects, regardless of the font size and the type of nonwords. Extending previous radical-based and character-based models, we propose a task/decision-sensitive character-driven processing model with a level-skipping assumption: Connections from the feature level bypass the lower radical level and link up directly to the higher character level.

A demonstration of attentional bias, using a novel dual task paradigm, towards clinically salient material in recovering alcohol abuse patients?

Background. This study examined whether alcohol abuse patients are characterized either by enhanced schematic processing of alcohol related cues or by an attentional bias towards the processing of alcohol cues. Method. Abstinent alcohol abusers (N = 25) and non-clinical control participants (N = 24) performed a dual task paradigm in which they had to make an odd/even decision to a centrally presented number while performing a peripherally presented lexical decision task. Stimuli on the lexical decision task comprised alcohol words, neutral words and non-words. In addition, participants completed an incidental recall task for the words presented in the lexical decision task. Results. It was found that, in the presence of alcohol related words, the performance of patients on the odd/even decision task was poorer than in the presence of other stimului. In addition, patients displayed slower lexical decision times for alcohol related words. Both groups displayed better recall for alcohol words than for other stimuli. Conclusions. These results are interpreted as supporting neither model of drug cravings. Rather, it is proposed that, in the presence of alcohol stimuli, alcohol abuse patients display a breakdown in the ability to focus attention.

The representation of delayed intentions: a prospective subject-performed task?

To-be-enacted material is more accessible in tests of recognition and lexical decision than material not intended for action (T. Goschke J. Kuhl, 1993; R. L. Marsh, J. L. Hicks, & M. L. Bink, 1998). This finding has been attributed to the superior status of intention-related information. The current article explores an alternative (action-superiority) account that draws parallels between the intended enactment effect (IEE) and the subject-performed task effect. Using 2 paradigms, the authors observed faster recognition latencies for both enacted and to-be-enacted material. It is crucial to note that there was no evidence of an IEE for items that had already been executed during encoding. The IEE was also eliminated when motor processing was prevented after verbal encoding. These findings suggest an overlap between overt and intended enactment and indicate that motor information may be activated for verbal material in preparation for subsequent execution.

Visual motion interferes with lexical decision on motion words

Embodied theories of cognition propose that neural substrates used in experiencing the referent of a word, for example perceiving upward motion, should be engaged in weaker form when that word, for example ‘rise’, is comprehended. Motivated by the finding that the perception of irrelevant background motion at near-threshold, but not supra-threshold, levels interferes with task execution, we assessed whether interference from near-threshold background motion was modulated by its congruence with the meaning of words (semantic content) when participants completed a lexical decision task (deciding if a string of letters is a real word or not). Reaction times for motion words, such as ‘rise’ or ‘fall’, were slower when the direction of visual motion and the ‘motion’ of the word were incongruent — but only when the visual motion was at nearthreshold levels. When motion was supra-threshold, the distribution of error rates, not reaction times, implicated low-level motion processing in the semantic processing of motion words. As the perception of near-threshold signals is not likely to be influenced by strategies, our results support a close contact between semantic information and perceptual systems.

Lexical access across languages: a multinomial model of auditory distraction

Recall in many types of verbal memory task is reliably disrupted by the presence of auditory distracters, with verbal distracters frequently proving the most disruptive (Beaman, 2005). A multinomial processing tree model (Schweickert, 1993) is applied to the effects on free recall of background speech from a known or an unknown language. The model reproduces the free recall curve and the impact on memory of verbal distracters for which a lexical entry exists (i.e., verbal items from a known language). The effects of semantic relatedness of distracters within a language is found to depend upon a redintegrative factor thought to reflect the contribution of the speech-production system. The differential impacts of known and unknown languages cannot be accounted for in this way, but the same effects of distraction are observed amongst bilinguals, regardless of distracter-language.

Lexical access, story re-telling and sequencing skills in adults who clutter and those who do not

Cluttering is a rate-based disorder of fluency, the scope of whose diagnostic criteria currently remains unclear. This paper reports preliminary findings from a larger study which aims to determine whether cluttering can be associated with language disturbances as well as motor and rate based ones. Subtests from the Mt Wilga High Level Language Test (MWHLLT) were used to determine whether people who clutter (PWC) have word finding difficulties, and use significantly more maze behaviours compared to controls, during story re-telling and simple sequencing tasks. Independent t tests showed that PWC were significantly slower than control participants in lexical access and sentence completion tasks, but returned mixed findings when PWCs were required to name items within a semantic category. PWC produced significantly more maze behaviour than controls in a task where participants were required to explain how to undertake commonly performed actions, but no difference in use of maze behaviour was found between the two groups when retelling a story from memory. The implications of these findings are discussed

Assessing L2 task performance: understanding effects of task design

The overarching aim of the research reported here was to investigate the effects of task structure and storyline complexity of oral narrative tasks on second language task performance. Participants were 60 Iranian language learners of English who performed six narrative tasks of varying degree of structure and storyline complexity in an assessment setting. A number of analytic detailed measures were employed to examine whether there were any differences in the participants’ performances elicited by the different tasks in terms of their accuracy, fluency, syntactic complexity and lexical diversity. Results of the data analysis showed that performance in the more structured tasks was more accurate and to a great extent more fluent than that in the less structured tasks. The results further revealed that syntactic complexity of L2 performance was related to the storyline complexity, i.e. more syntactic complexity was associated with narratives that had both foreground and background storylines. These findings strongly suggest that there is some unsystematic variance in the participants’ performance triggered by the different aspects of task design.

Task design and second language performance: the effect of narrative type on learner output

This article reports on a detailed empirical study of the way narrative task design influences the oral performance of second-language (L2) learners. Building on previous research findings, two dimensions of narrative design were chosen for investigation: narrative complexity and inherent narrative structure. Narrative complexity refers to the presence of simultaneous storylines; in this case, we compared single-story narratives with dual-story narratives. Inherent narrative structure refers to the order of events in a narrative; we compared narratives where this was fixed to others where the events could be reordered without loss of coherence. Additionally, we explored the influence of learning context on performance by gathering data from two comparable groups of participants: 60 learners in a foreign language context in Teheran and 40 in an L2 context in London. All participants recounted two of four narratives from cartoon pictures prompts, giving a between-subjects design for narrative complexity and a within-subjects design for inherent narrative structure. The results show clearly that for both groups, L2 performance was affected by the design of the task: Syntactic complexity was supported by narrative storyline complexity and grammatical accuracy was supported by an inherently fixed narrative structure. We reason that the task of recounting simultaneous events leads learners into attempting more hypotactic language, such as subordinate clauses that follow, for example, while, although, at the same time as, etc. We reason also that a tight narrative structure allows learners to achieve greater accuracy in the L2 (within minutes of performing less accurately on a loosely structured narrative) because the tight ordering of events releases attentional resources that would otherwise be spent on finding connections between the pictures. The learning context was shown to have no effect on either accuracy or fluency but an unexpectedly clear effect on syntactic complexity and lexical diversity. The learners in London seem to have benefited from being in the target language environment by developing not more accurate grammar but a more diverse resource of English words and syntactic choices. In a companion article (Foster & Tavakoli, 2009) we compared their performance with native-speaker baseline data and see that, in terms of nativelike selection of vocabulary and phrasing, the learners in London are closing in on native-speaker norms. The study provides empirical evidence that L2 performance is affected by task design in predictable ways. It also shows that living within the target language environment, and presumably using the L2 in a host of everyday tasks outside the classroom, confers a distinct lexical advantage, not a grammatical one.

Immediate auditory repetition of words and nonwords: An ERP study of lexical and sublexical processing

ERPs were elicited to (1) words, (2) pseudowords derived from these words, and (3) nonwords with no lexical neighbors, in a task involving listening to immediately repeated auditory stimuli. There was a significant early (P200) effect of phonotactic probability in the first auditory presentation, which discriminated words and pseudowords from nonwords; and a significant somewhat later (N400) effect of lexicality, which discriminated words from pseudowords and nonwords. There was no reliable effect of lexicality in the ERPs to the second auditory presentation. We conclude that early sublexical phonological processing differed according to phonotactic probability of the stimuli, and that lexically-based redintegration occurred for words but did not occur for pseudowords or nonwords. Thus, in online word recognition and immediate retrieval, phonological and/or sublexical processing plays a more important role than lexical level redintegration.