Hemispheric asymmetries in the split-fovea model of semantic processing

We report a series of neural network models of semantic processing of single English words in the left and the right hemispheres of the brain. We implement the foveal splitting of the visual field and assess the influence of this splitting on a mapping from orthography to semantic representations in single word reading. The models were trained on English four-letter words, presented according to their frequency in all positions encountered during normal reading. The architecture of the model interacted with the training set to produce processing asymmetries comparable to those found in behavioral studies. First, the cueing effects of dominant and subordinate meanings of ambiguous words were different for words presented to the left or to the right of the input layer. Second, priming effects of groups of related words were stronger in the left input than the right input of the model. These effects were caused by coarser-coding in the right half compared with the left half of the model, an emergent effect of the split model interacting with informational asymmetries in the left and right parts of words in the lexicon of English. Some or all of the behavioral data for reading single words in English may have a similar origin.     

Principles and practice in reporting structural equation analyses

Principles for reporting analyses using structural equation modeling are reviewed, with the goal of supplying readers with complete and accurate information. It is recommended that every report give a detailed justification of the model used, along with plausible alternatives and an account of identifiability. Nonnormality and missing data problems should also be addressed. A complete set of parameters and their standard errors is desirable, and it will often be convenient to supply the correlation matrix and discrepancies, as well as goodness-of-fit indices, so that readers can exercise independent critical judgment. A survey of fairly representative studies compares recent practice with the principles of reporting recommended here.     

Involuntary listening aids seeing: evidence from human electrophysiology

It is well known that sensory events of one modality can influence judgments of sensory events in other modalities. For example, people respond more quickly to a target appearing at the location of a previous cue than to a target appearing at another location, even when the two stimuli are from different modalities. Such cross-modal interactions suggest that involuntary spatial attention mechanisms are not entirely modality-specific. In the present study, event-related brain potentials (ERPs) were recorded to elucidate the neural basis and timing of involuntary, cross-modal spatial attention effects. We found that orienting spatial attention to an irrelevant sound modulates the ERP to a subsequent visual target over modality-specific, extrastriate visual cortex, but only after the initial stages of sensory processing are completed. These findings are consistent with the proposal that involuntary spatial attention orienting to auditory and visual stimuli involves shared, or at least linked, brain mechanisms.     

Eye movements reveal the on-line computation of lexical probabilities during reading

Skilled readers are able to derive meaning from a stream of visual input with remarkable efficiency. In this article, we present the first evidence that statistical information latent in the linguistic environment can contribute to an account of reading behavior. In two eye-tracking studies, we demonstrate that the transitional probabilities between words have a measurable influence on fixation durations, and using a simple Bayesian statistical model, we show that lexical probabilities derived by combining transitional probability with the prior probability of a word's occurrence provide the most parsimonious account of the eye movement data. We suggest that the brain is able to draw upon statistical information in order to rapidly estimate the lexical probabilities of upcoming words: a computationally inexpensive mechanism that may underlie proficient reading.     

Early adolescents' experiences with, and views of, Barbie

There has been a great deal of debate over the influence of Barbie dolls on girls' developing self-concept and body image. Two qualitative studies were conducted to gather information about early adolescents' experiences with, and perspectives on, the controversial toy. In Study 1, focus groups with twenty 6th-grade girls suggested that they have ambiguous feelings toward the doll and the feminine sexualized image it represents. Study 2 gathered essay responses from fifty 7th- and 8th-grade boys and girls regarding their experiences with, and opinions on, Barbie dolls. Participants reported both positive and negative feelings toward the doll and its influence on girls' development.     

The potential contribution of preplanned refixations to the preferred viewing location

On the basis of recent evidence for the preplanning of refixation saccades in reading-like tasks (e.g., Beauvillain, Vergilino, & Dukic, 2000), we proposed that for a proportion of words refixated during natural reading, the refixation sequence is planned before the word is fixated, and that the saccade target for these cases is near the beginning of the word. The preferred viewing location (PVL) phenomenon can then be explained as a mixture of two populations of planned saccades: those that initiate a multiple-fixation sequence and single fixations. This account supplants saccadic undershooting as the primary determinant of the PVL. We used a corpus of eye movement data to show that the probability of refixation is strongly correlated with the estimated perceptibility of the target word from the current fixation location, and that the observed (re-)fixation behavior is justified when assessed in terms of a lexical uncertainty measure. Refixations may be preplanned in order to increase the chances of successful word identification.     

Identifying the nature of impairments in executive functioning and working memory of children with severe difficulties in arithmetic

An age-matched achievement-matched design was used to examine whether the executive functioning and working memory impairments exhibited by children with severe difficulties in arithmetic (SDA) are better viewed as developmental lags or as cognitive deficits. Three groups of children were included: 20 SDA children, 20 typically achieving children (CM) matched in chronological age with the SDA children, and 20 younger typically achieving children (AM) matched in achievement with the SDA group. While children with SDA did not exhibit impairments in color-word inhibition and verbal working memory, they did demonstrate impairments in shifting, quantity-digits inhibition, and visuospatial working memory. As children with SDA did not perform more poorly than their AM counterparts on any of these tasks, impairments in specific areas of executive functioning and working memory appear to reflect developmental lags rather than cognitive deficits.     

Interspersing easy math problems among challenging problems: detection of interspersal effects in whole-class applications

Interspersing easy problems among challenging problems has been shown to both increase students’ preference for completing math worksheets and the fluency with which they complete challenging problems. Although early research examining the interspersal procedure in mathematics was conducted with college-age students, there are a growing number of studies utilizing the interspersal procedure in elementary and secondary school settings. A particular concern with existing research however is whether the beneficial effects are maintained across multiple sessions and whether effects generalize when implemented with large groups of students. The current study addressed this concern by administering both control and interspersal math worksheets consisting of instructionally relevant problems to 75 fourth grade students across four sessions. Because students’ instructional levels differed, analyses were conducted separately for students identified as fluent and less fluent based upon student performance on the control worksheet administered during session 1. Dependent measures included digits correct and problems correct as well as students’ responses to four preference questions following each session. Although results differ from previous research in that students completed significantly more digits correct on control worksheets, explanations of these differences are examined and implications are discussed.     

Links between behavioral regulation and preschoolers' literacy, vocabulary, and math skills

This study investigated predictive relations between preschoolers' (N=310) behavioral regulation and emergent literacy, vocabulary, and math skills. Behavioral regulation was assessed using a direct measure called the Head-to-Toes Task, which taps inhibitory control, attention, and working memory, and requires children to perform the opposite of what is instructed verbally. Hierarchical linear modeling (HLM) was utilized because children were nested in 54 classrooms at 2 geographical sites. Results revealed that behavioral regulation significantly and positively predicted fall and spring emergent literacy, vocabulary, and math skills on the Woodcock Johnson Tests of Achievement (all ps<.05). Moreover, growth in behavioral regulation predicted growth in emergent literacy, vocabulary, and math skills over the prekindergarten year (all ps<.05), after controlling for site, child gender, and other background variables. Discussion focuses on the role of behavioral regulation in early academic achievement and preparedness for kindergarten.