初级视觉皮层在注意振荡中的作用

注意离散性是注意间歇性地采集外界信息的特性, 这种特性在行为中的表现被称为注意振荡。尽管有研究使用经典的线索靶子范式和视觉搜索范式发现行为数据中存在注意振荡, 证明了注意是离散的, 但其相应的神经机制, 即注意离散性与哪些脑区有关, 尚不明确。研究采用高时间分辨率的线索靶子范式和双眼分视技术, 基于人眼视觉通路的解剖学特性, 比较了线索靶子出现在双眼(实验1)、同眼和异眼(实验2)条件下的注意振荡, 考察初级视觉皮层对注意振荡的影响。结果发现：1)双眼分视会对注意振荡发生的频段产生影响, 非双眼分视条件下, 注意振荡出现在低频(2 Hz和8 Hz)。而双眼分视条件下, 注意振荡则出现在更高的频段(12.5 Hz)。2)无论线索靶子出现在同眼还是异眼, 注意振荡的频段无显著差异。结果表明V1区双眼视觉通路或者更高级的视觉区可能参与注意振荡, 为探明注意振荡的神经机制提供了重要的行为学证据。     

Two good reasons to say ‘change!’ – ensemble representations as well as item representations impact standard measures of VWM capacity

Visual working memory (VWM) is a central bottleneck in human information processing. Its capacity is most often measured in terms of how many individual‐item representations VWM can hold (k). In the standard task employed to estimate k, an array of highly discriminable colour patches is maintained and, after a short retention interval, compared to a test display (change detection). Recent research has shown that with more complex, structured displays, change‐detection performance is, in addition to individual‐item representations, supported by ensemble representations formed as a result of spatial subgroupings. Here, by asking participants to additionally localize the change, we reveal indication for an influence of ensemble representations even in the very simple, unstructured displays of the colour‐patch change‐detection task. Critically, pure‐item models from which standard formulae of k are derived do not consider ensemble representations and, therefore, potentially overestimate k. To gauge this overestimation, we develop an item‐plus‐ensemble model of change detection and change localization. Estimates of k from this new model are about 1 item (~30%) lower than the estimates from traditional pure‐item models, even if derived from the same data sets.     

两种教学方法对不同认知风格11岁儿童数学学习效果的影响

比较运用尝试教学法教学和常规教学法教学对小学五年级独立型和场依存型的学生在解决三种难度的百分数应用题中的效果.结果发现:(1)从整体上看,在高难度题的测试中,以尝试教学法教学的成绩明显高于以常规教学法教学的成绩,两者的差异达到显著水平.对场依存的学生,在低难度题测试时,两种教学方法取得的成绩无显著差异;在中难度题测试时,以常规教学法教学的成绩高于以尝试教学法教学的成绩,差异达到显著水平;在高难度题测试时,以尝试教学法教学的成绩高于以常规教学法教学的成绩,两者的差异达到显著水平.对场独立的学生在低难度题测试时,两种教学方法取得的成绩无显著差异;在中、高难度题测试时,以尝试教学法教学的成绩均高于以常规教学法教学的成绩,差异达到显著水平.(2)从整体来看,在题为高难度时男生的成绩高于女生,差异达到显著水平,而在低、中难度时无显著的性别差异.场依存者在题为低难度时女生的成绩高于男生差异达到显著水平,而中、高难度时无显著的性别差异.场独立者在高难度时男生的成绩高于女生,差异达到显著水平.     

视觉搜索中多目标追踪的研究

在视觉信息的选择加工过程中 ,只有很少信息能够通过注意系统得到进一步的认知加工 ,其中视觉搜索起着十分重要的作用。本研究基于动态视觉信息注意追踪的研究 ,采用 3× 2× 2的实验设计 ,从如下三方面对注意追踪的规律进行了探讨 :(1)分心物数量 (1,5和 9)的变化对多目标注意追踪的影响 ;(2 )目标的显著性 (特征变化和特征不变 )对多目标注意追踪的影响 ;(3)目标运动形式 (目标随机运动和目标运动形式不变 )对多目标注意追踪的影响。研究结果表明 :(1)分心物数量的增加对目标的注意识别没有抑制作用 ;(2 )特征变化目标的注意识别速度显著高于特征不变的目标 ;(3)运动形式不变的目标较运动形式变化目标的注意识别速度快。     

Arithmetic operation and working memory: differential suppression in dual tasks

The relationship between arithmetic function and working memory was examined using a dual-task paradigm for either phonological or visuo-spatial suppression. Simultaneous phonological rehearsal significantly delayed the performance of multiplication but not subtraction, whereas holding an image in the mind delayed subtraction but not multiplication. This result indicates that arithmetic function is related to working memory in a subsystem-specific manner: multiplication is more closely linked to phonological loop and subtraction to visuo-spatial sketchpad. Whereas this is not compatible with the notion that arithmetic is done on a unitary, amodal representation of numbers, it provides support for the triple-code and/or the modular processing models on human numerical cognition in which number representations are specific for input/output modality and arithmetic types.     

The development of visual search in infants and very young children.

In two experiments, 90 1- to 3-year-olds were trained in a new nonverbal task to touch a video screen that displayed a unique target resembling a popular television character. The target appeared among varying numbers of distractors that resembled another familiar television character and was either a uniquely colored shape (the feature search task) or a unique color-shape combination (the conjunction search task). Each correct response triggered a sound and produced four animated objects on the screen. Irrespective of age and experimental design (between-subjects or within-subjects), children's reaction time (RT) patterns resembled those obtained from adults in corresponding search tasks: The RT slope for feature search was flat and independent of distractor number, whereas the RT slope for conjunction search increased linearly with distractor number. These results extend visual search effects found with adults to infants and very young children and suggest that the basic perceptual processes underlying visual search are qualitatively invariant over ontogeny.     

Distinctive phonological features differ in relevance for both spoken and written word recognition

This paper discusses four experiments on Dutch which show that distinctive phonological features differ in their relevance for word recognition. The relevance of a feature for word recognition depends on its phonological stability, that is, the extent to which that feature is generally realized in accordance with its lexical specification in the relevant word position. If one feature value is uninformative, all values of that feature are less relevant for word recognition, with the least informative feature being the least relevant. Features differ in their relevance both in spoken and written word recognition, though the differences are more pronounced in auditory lexical decision than in self-paced reading.     

Phonological processing of words in right- and left-handers

It is commonly accepted that phonology is the exclusive domain of the left hemisphere. However, this pattern of lateralization, which posits a right visual field advantage, has been questioned by several studies. In fact, certain factors such as characteristics of the stimuli and subjects' handedness can modulate the right visual field advantage. Thus, the goal of this study was to compare the hemispheric dynamics of right-handers and left-handers during a divided visual field presentation of words that varied in terms of their phonological transparency. For non-transparent words, the left hemisphere seems more competent in both handedness groups. With regard to transparent words, the right hemisphere of both groups also appears competent. Surprisingly, left-handers achieved optimal processing with a functionally isolated left hemisphere, whereas right-handers needed the participation of both hemispheres. The pattern of performance cannot be fully explained by either the callosal or the direct access model.     

Queuing or sharing? A critical evaluation of the single-bottleneck notion

The model of a single central bottleneck for human information processing is critically examined. Most evidence cited in support of the model has been observed within the overlapping tasks paradigm. It is shown here that most findings obtained within that paradigm and that were used to support the model are also consistent with a simple resource model. The most prominent findings are the millisecond-for-millisecond slope at the left of the RT2-SOA curve, the high RT1-RT2 correlation, the additivity of the effects on RT2 of SOA and of the difficulty of selecting R2, and the washout of the effect of S2 discriminability on RT2 in a dual-task condition. In addition, the asymmetry of the effects of the dual-task requirement on RT1 and RT2 can be accounted for by the resource model provided that it assumes uneven allocation of resources, which is quite reasonable in view of the task asymmetry inherent in the demand characteristics of the paradigm. The same is true for two other findings that appear to support the single-bottleneck model-that in the dual-task condition, the demand of the first task affects equally RT1 and RT2 and that its effect on RT1 is the same as the corresponding effect in the single-task condition. Furthermore, the single-bottleneck model is hard to reconcile with a negative slope at the left of the RT1-SOA curve or a positive slope at the left of the IRI-SOA curve, unless augmented by ancillary assumptions that are yet to be substantiated. Representative data were fit by each of the models using its optimal set of parameters. Both models achieved quite good degrees of fit. It is further argued that since the overlapping tasks paradigm is heavily biased in favor of a speedy reaction to the stimulus that appears first, it is nonoptimal for testing the central bottleneck model. Finally, the bottleneck model is examined in terms of other scientific criteria.