Assessment of working memory components at 6years of age as predictors of reading achievements a year later

The ability of working memory skills (measured by tasks assessing all four working memory components), IQ, language, phonological awareness, literacy, rapid naming, and speed of processing at 6 years of age, before reading was taught, to predict reading abilities (decoding, reading comprehension, and reading time) a year later was examined in 97 children. Among all working memory components, phonological complex memory contributed most to predicting all three reading abilities. A capacity measure of phonological complex memory, based on passing a minimum threshold in those tasks, contributed to the explained variance of decoding and reading comprehension. Findings suggest that a minimal ability of phonological complex memory is necessary for children to attain a normal reading level. Adding assessment of phonological complex memory, before formal teaching of reading begins, to more common measures might better estimate children’s likelihood of future academic success.     

An Extension of SIC Predictions to the Wiener Coactive Model

The survivor interaction contrasts (SIC) is a powerful measure for distinguishing among candidate models of human information processing. One class of models to which SIC analysis can apply are the coactive, or channel summation, models of human information processing. In general, parametric forms of coactive models assume that responses are made based on the first passage time across a fixed threshold of a sum of stochastic processes. Previous work has shown that the SIC for a coactive model based on the sum of Poisson processes has a distinctive down-up-down form, with an early negative region that is smaller than the later positive region. In this note, we demonstrate that a coactive process based on the sum of two Wiener processes has the same SIC form.     

Learning to learn: From within-modality to cross-modality transfer during infancy

One critical aspect of learning is the ability to apply learned knowledge to new situations. This ability to transfer is often limited, and its development is not well understood. The current research investigated the development of transfer between 8 and 16 months of age. In Experiment 1, 8- and 16-month-olds (who were established to have a preference to the beginning of a visual sequence) were trained to attend to the end of a sequence. They were then tested on novel visual sequences. Results indicated transfer of learning, with both groups changing baseline preferences as a result of training. In Experiment 2, participants were trained to attend to the end of a visual sequence and were then tested on an auditory sequence. Unlike Experiment 1, only older participants exhibited transfer of learning by changing baseline preferences. These findings suggest that the generalization of learning becomes broader with development, with transfer across modalities developing later than transfer within a modality.     

Working memory components as predictors of children's mathematical word problem solving

This study determined the working memory (WM) components (executive, phonological loop, and visual–spatial sketchpad) that best predicted mathematical word problem-solving accuracy of elementary school children in Grades 2, 3, and 4 (N = 310). A battery of tests was administered to assess problem-solving accuracy, problem-solving processes, WM, reading, and math calculation. Structural equation modeling analyses indicated that (a) all three WM components significantly predicted problem-solving accuracy, (b) reading skills and calculation proficiency mediated the predictive effects of the central executive system and the phonological loop on solution accuracy, and (c) academic mediators failed to moderate the relationship between the visual–spatial sketchpad and solution accuracy. The results support the notion that all components of WM play a major role in predicting problem-solving accuracy, but basic skills acquired in specific academic domains (reading and math) can compensate for some of the influence of WM on children’s mathematical word problem solving.     

Number of sense effects of Chinese disyllabic compounds in the two hemispheres

The current study manipulated the visual field and the number of senses of the first character in Chinese disyllabic compounds to investigate how the related senses (polysemy) of the constituted character in the compounds were represented and processed in the two hemispheres. The ERP results in experiment 1 revealed crossover patterns in the left hemisphere (LH) and the right hemisphere (RH). The sense facilitation in the LH was in favor of the assumption of single-entry representation for senses. However, the patterns in the RH yielded two possible interpretations: (1) the nature of hemispheric processing in dealing with sublexical sense ambiguity; (2) the semantic activation from the separate-entry representation for senses. To clarify these possibilities, experiment 2 was designed to push participants to a deeper level of lexical processing by the word class judgment. The results revealed the sense facilitation effect in the RH. In sum, the current study was in support of the single-entry account for related senses and demonstrated that two hemispheres processed sublexical sense ambiguity in a complementary way.     

Exploring an integrative model of infant behavior: what is the relationship among temperament, sensory processing, and neurobehavioral measures?

Traditionally, developmental psychology, occupational/physical therapy, and behavioral pediatrics view similar infant behaviors from temperament, sensory processing, or neurobehavioral theoretical perspectives. This study examined the relations between similar and unique summary scores of three infant assessments (Early Infancy Temperament Questionnaire - EITQ, the Infant Sensory Profile - ISP, and the NICU Network Neurobehavioral Scale - NNNS) in a healthy sample of 100, one-month-old infants. A Principal Components Analysis of selected subscale scores derived from the three assessments suggested a three-factor model. Temperament and sensory summary scores had the strongest relations on two factors: Sensory-Affective Reactivity and Engagement. A third factor had strong relations between state regulation and motor competence. This new integrative model also validates an existing model and expands explanation of infant behavior across disciplines and methods which have significant implications for assessment, intervention, and management practices.     

Are historic years understood as numbers or events? An fMRI study of numbers with semantic associations

While numbers generally cue processing of quantity or order, they can also contain semantic information, as in the case of historic years (e.g., “1492” calls forth associations of Columbus sailing the ocean blue). Whether these dates are processed as quantities or events may depend on the context in which they occur. We examined such “ambiguous number” processing in two different contexts using a paired-comparison task, recording both behavioral responses and brain activity. Participants were either asked to think of all items as numbers and to choose the larger number, or were told to treat the comparators as events and to choose the later event. Behaviorally, all events showed a normal distance effect, establishing that they may be understood and compared in an ordinal sequence. Functional magnetic resonance imaging (fMRI) demonstrated significant differences between years when treated as numbers versus as events. Dates in both contexts shared activity in parietal lobe regions previously implicated in number processing. Dates as numbers showed no extra-numeric activity, while dates thought of as events evoked activity in temporal semantic processing and frontal semantic retrieval areas. These differences suggest that extra-numeric information may be easily accessed and incorporated during processing when supported by even a weak context. This work supports previous studies showing a dissociation between quantity and meaning, and illustrates the brain areas involved in these different aspects.     

Does a sensory processing deficit explain counting accuracy on rapid visual sequencing tasks in adults with and without dyslexia?

The experiments conducted aimed to investigate whether reduced accuracy when counting stimuli presented in rapid temporal sequence in adults with dyslexia could be explained by a sensory processing deficit, a general slowing in processing speed or difficulties shifting attention between stimuli. To achieve these aims, the influence of the inter-stimulus interval (ISI), stimulus duration, and sequence length were evaluated in two experiments. In the first that used skilled readers only, significantly more errors were found with presentation of long sequences when the ISI or stimulus durations were short. Experiment 2 used a wider range of ISIs and stimulus durations. Compared to skilled readers, a group with dyslexia had reduced accuracy on two-stimulus sequences when the ISI was short, but not when the ISI was long. Although reduced accuracy was found on all short and long sequences by the group with dyslexia, when performance on two-stimulus sequences was used as an index of sensory processing efficiency and controlled, group differences were found with presentation of stimuli of short duration only. We concluded that continuous, repetitive stimulation to the same visual area can produce a capacity limitation on rapid counting tasks in all readers when the ISIs or stimulus durations are short. While reduced accuracy on rapid sequential counting tasks can be explained by a sensory processing deficit when the stimulus duration is long, slower processing speed in the group with dyslexia explains the greater inaccuracy found as sequence length is increased when the stimulus duration is short.     

Do conscious perception and unconscious processing rely on independent mechanisms? A meta-contrast study

There is currently no consensus regarding what measures are most valid to demonstrate perceptual processing without awareness. Likewise, whether conscious perception and unconscious processing rely on independent mechanisms or lie on a continuum remains a matter of debate. Here, we addressed these issues by comparing the time courses of subjective reports, objective discrimination performance and response priming during meta-contrast masking, under similar attentional demands. We found these to be strikingly similar, suggesting that conscious perception and unconscious processing cannot be dissociated by their time course. Our results also demonstrate that unconscious processing, indexed by response priming, occurs, and that objective discrimination performance indexes the same conscious processes as subjective visibility reports. Finally, our results underscore the role of attention by showing that how much attention the stimulus receives relative to the mask, rather than whether processing is measured by conscious discrimination or by priming, determines the time course of meta-contrast masking.