First and second language vowel perception in early bilinguals

Previous research has shown that the perception of speech sounds is strongly influenced by the internal structure of maternal language categories. Specifically, it has been shown that stimuli judged as good exemplars of a phonemic category are more difficult to discriminate from similar sounds than bad exemplars from equally similar sounds. This effect seems to be restricted to phonemes present in the maternal language, and is acquired in the first months of life. The present study investigates the malleability of speech acquisition by analysing the discrimination capacities for L2 phonemes in highly proficient Spanish-Catalan bilinguals born in monolingual families. In Experiment I subjects were required to give goodness of fit judgments to establish the best exemplars corresponding to three different vowel categories (Catalan /e/ and /ε/ Spanish /e/). In Experiments 2 and 3, bilinguals were asked to perform a discrimination task with materials in their maternal language (Exp. 2) and in their second language (Exp. 3). Results reveal that bilinguals show a reduced discrimination capacity only for good exemplars of their maternal language, but not for good exemplars of their second language. The same pattern of results was obtained in Experiment 4, using a within-subjects design and a bias-free discrimination measure (d'). These findings support the hypothesis that phonemic categories are not only acquired early in life, but under some circumstances, the acquisition of new phonemic categories can be seriously compromised, in spite of early and extensive exposure to L2.     

A dissociation between the sense of familiarity and access to semantic information concerning familiar people

In the current study we examined the relationship between working memory capacity, inhibition/susceptibility to interference and fluid intelligence, measured by the Raven's Progressive Matrices (PM38), comparing groups of young (aged 18–35), young-old (aged 65–74), and old-old (aged 75–86) participants. Groups were administered two working memory tasks tapping into different mechanisms involved in working memory. The ability to control for irrelevant information was measured both considering memory errors (intrusion errors) in a working memory task and an index of susceptibility to interference obtained with a variant of the Brown-Peterson task. Regression analyses showed that the classical working memory measure was the most potent predictors of the Raven's score. Susceptibility to interference and intrusions errors contributed, but to a lower extent, to the Raven explained variance. These results confirm that working memory shares cognitive aspects with the fluid intelligence measure considered, whereas the role of inhibition to Raven scores is still in need of better evidence.     

More than a surprise: The bivalency effect in task switching

When switching tasks, if stimuli are presented that contain features that cue two of the tasks in the set (i.e., bivalent stimuli), performance slowing is observed on all tasks. This generalized slowing extends to tasks in the set which have no features in common with the bivalent stimulus and is referred to as the bivalency effect. In previous work, the bivalency effect was invoked by presenting occasionally occurring bivalent stimuli; therefore, the possibility that the generalized slowing is simply due to surprise (as opposed to bivalency) has not yet been discounted. This question was addressed in two task switching experiments where the occasionally occurring stimuli were either bivalent (bivalent version) or merely surprising (surprising version). The results confirmed that the generalized slowing was much greater in the bivalent version of both experiments, demonstrating that the magnitude of this effect is greater than can be accounted for by simple surprise. This set of results confirms that slowing task execution when encountering bivalent stimuli may be fundamental for efficient task switching, as adaptive tuning of response style may serve to prepare the cognitive system for possible future high conflict trials.     

Voluntary language switching in English–Spanish bilingual children

Although bilingual children frequently switch between languages, the psycholinguistic mechanisms underlying the emerging ability to control language choice are unknown. We examined the mechanisms of voluntary language switching in English–Spanish bilingual children during a picture-naming task under two conditions: (1) single-language naming in English and in Spanish; (2) either-language naming, when the children could use whichever language they wanted. The mechanism of inhibitory control was examined by analysing local switching costs and global mixing costs. The mechanism of lexical accessibility was examined by analysing the properties of the items children chose to name in their non-dominant language. The children exhibited significant switching costs across both languages and asymmetrical mixing costs; they also switched into their non-dominant language most frequently on highly accessible items. These findings suggest that both lexical accessibility and inhibition contribute to language choice during voluntary language switching in children.     

The other modality: Auditory stimuli in language switching

Language switching studies typically implement visual stimuli and visual language cues to trigger a concept and a language response, respectively. In the present study we set out to generalise this to another stimulus modality by investigating language switching with auditory stimuli next to visual stimuli. The results showed that switch costs can be obtained with both auditory and visual stimuli. Yet, switch costs were relatively larger with visual stimuli than with auditory stimuli. Both methodological and theoretical implications of these findings are discussed.     

Automatic shifts of attention in the Dimensional Change Card Sort task: Subtle changes in task materials lead to flexible switching

Two experiments tested a hypothesis that reducing demands on executive control in a Dimensional Change Card Sort task will lead to improved performance in 3-year-olds. In Experiment 1, the shape dimension was represented by two dissimilar values (stars and flowers), and the color dimension was represented by two similar values (red and pink). This configuration of stimuli rendered shape more salient than color. In Experiment 2, attentional weights of each dimension value were manipulated by using two versus four values to represent the dimensions of shape and color. The results indicated that increasing saliency of the postswitch dimension (Experiment 1) and reducing attentional weights of individual dimension values (Experiment 2) lead to a marked improvement in the postswitch sorting accuracy in 3-year-olds.     

准备时间和预先信息对任务切换的影响

两个实验采用任务线索范式,考察了准备时间和预先信息对任务切换的影响。实验1的准备时间为可预测,实验2的为不可预测,以考察准备时间的可预测性对任务切换的影响。以被试执行重复任务、切到任务和切离任务的正确反应时为主要指标,结果：（1）在准备时间可预测和不可预测两种条件下,准备时间和预先信息之间存在显著交互作用。在可预测条件中,重复和切到任务的反应时随着准备时间的增加而减少,但切到代价无显著变化,切离任务的反应时不受准备时间的影响,切离代价表现出反准备效应;不可预测条件下,三种任务的反应时都随着准备时间的增加而减少,但是切到和切离代价表现出反准备效应;（2）切离任务的反应时和代价显著高于切到任务的反应时和代价;（3）在这两种条件下,都没有出现切换代价的准备效应     

汉-英双语者言语理解中语码切换的机制——来自亚词汇水平的证据

以汉字义符和英文词后缀为对象,考察了汉-英双语者语码切换的机制及切换代价的来源。结果表明:(1)在亚词汇水平上,汉字义符和英文词后缀影响字词认知的过程,但对语码切换代价的影响不显著,支持语码切换与任务转换的发生机制相同的观点。(2)语言熟练程度是影响语码切换代价及切换代价不对称性的主要原因。整个研究表明,在亚词汇水平上,语码切换与任务转换的实质相同。参考任务转换中切换代价的来源,归纳了语码切换代价的可能来源。