Wim Van den Broeck

Segmenting two-phoneme syllables: developmental differences in relation with early reading skills.

This study explored developmental differences in childrens segmentation skills of VC and CV syllables (e.g., /af/ and /fa/) in relation to their early reading abilities. To this end, we followed a subgroup of Dutch speaking prereaders who participated in, and replicated the segmentation task in first grade, at the outset of phonics reading instruction. Reading abilities were assessed after 6 and 9 months. First, we confirmed that VCs offer an easier context to isolate phonemes than CVs. Second, matching analyses showed that this development from VC to CV segmentation posed comparatively increasing difficulties for poor segmenters. Third, this qualitatively different development was reflected in early reading performance. Our data emphasize the importance of phonetic factors and instruction-based experiences in phonological development.

The Misconception of the Regression-Based Discrepancy Operationalization in the Definition and Research of Learning Disabilities

In this article, I argue that the regression-based discrepancy method used in the diagnosis of learning disabilities is invalid because it is inconsistent with the underlying underachievement concept of which it is intended to be the operationalization. I mathematically demonstrate that the regression-based discrepancy method largely reflects achievement-specific determinants, thereby defeating its own object of describing aptitude-achievement discrepancies. The implications for research examining the role of intelligence in learning disabilities are outlined.In this article, I argue that the regression-based discrepancy method used in the diagnosis of learning disabilities is invalid because it is inconsistent with the underlying underachievement concept of which it is intended to be the operationalization. I mathematically demonstrate that the regression-based discrepancy method largely reflects achievement-specific determinants, thereby defeating its own object of describing aptitude-achievement discrepancies. The implications for research examining the role of intelligence in learning disabilities are outlined.

Factorial validity and measurement invariance across intelligence levels and gender of the overexcitabilities questionnaire-II (OEQ-II).

The concept of overexcitability, derived from Dabrowskis theory of personality development, offers a promising approach for the study of the developmental dynamics of giftedness. The present study aimed at (a) examining the factorial structure of the Overexcitabilities Questionnaire-II scores (OEQ-II) and (b) testing measurement invariance of these scores across intelligence and gender. A sample of 641 Dutch-speaking adolescents from 11 to 15 years old, 363 girls and 278 boys, participated in this study. Results showed that a model without cross-loadings did not fit the data well (using confirmatory factor analysis), whereas a factor model in which all cross-loadings were included yielded fit statistics that were in support of the factorial structure of the OEQ-II scores (using exploratory structural equation modeling). Furthermore, our findings supported the assumption of (partial) strict measurement invariance of the OEQ-II scores across intelligence levels and across gender. Such levels of measurement invariance allow valid comparisons between factor means and factor relationships across groups. In particular, the gifted group scored significantly higher on intellectual and sensual overexcitability (OE) than the nongifted group, girls scored higher on emotional and sensual OE than boys, and boys scored higher on intellectual and psychomotor OE than girls.

No solid empirical evidence for the SOLID (serial order learning impairment) hypothesis of dyslexia.

This article reports on 2 studies that attempted to replicate the findings of a study by Szmalec, Loncke, Page, and Duyck (2011) on Hebb repetition learning in dyslexic individuals, from which these authors concluded that dyslexics suffer from a deficit in long-term learning of serial order information. In 2 experiments, 1 on adolescents (N = 59) and 1 on children (N = 57), no empirical evidence was obtained for impaired Hebb learning in dyslexics, whether the same data-analytical procedure as Szmalec et al. was used or whether some methodological improvements were applied (e.g., using a more sensitive index of Hebb learning, and equating groups on filler performance with state trace analysis). In an additional state trace analysis, aggregating data over participants, it was shown that performance on the repeated Hebb sequences was almost perfectly predictable from performance on the nonrepeated sequences (fillers). The implications of these findings are outlined for the current discussion on the mechanisms for encoding immediate serial recall and long-term sequence learning and for computational models attempting to simulate these mechanisms.

Order short-term memory is not impaired in dyslexia and does not affect orthographic learning

This article reports two studies that investigate short-term memory (STM) deficits in dyslexic children and explores the relationship between STM and reading acquisition. In the first experiment, 36 dyslexic children and 61 control children performed an item STM task and a serial order STM task. The results of this experiment show that dyslexic children do not suffer from a specific serial order STM deficit. In addition, the results demonstrate that phonological processing skills are as closely related to both item STM and serial order STM. However, non-verbal intelligence was more strongly involved in serial order STM than in item STM. In the second experiment, the same two STM tasks were administered and reading acquisition was assessed by measuring orthographic learning in a group of 188 children. The results of this study show that orthographic learning is exclusively related to item STM and not to order STM. It is concluded that serial order STM is not the right place to look for a causal explanation of reading disability, nor for differences in word reading acquisition.

The nonword-reading deficit of disabled readers: a developmental interpretation.

This article presents empirical evidence challenging the received wisdom that a nonword-reading deficit is a characteristic trait of disabled readers. On the basis of 2 large-scale empirical studies using the reading-level match design, we argue that a nonword-reading deficit is the consequence of normal developmental differences in word-specific knowledge between disabled readers and younger normal readers (both groups being matched on real-word reading). The first study shows that the nonword-reading deficit varies as a function of age and reading level and that this deficit is not typical for disabled readers. The second study demonstrates that a nonword-reading deficit crucially depends on the sensitivity of the matching word reading task to detect age-related differences in word-specific knowledge between disabled and normal readers. We clarify how these findings can be interpreted within the current framework of the phonological deficit hypothesis and discuss implications for theories of reading development.

Orthographic Learning and the Role of Text-to-Speech Software in Dutch Disabled Readers:

In this study, we examined whether orthographic learning can be demonstrated in disabled readers learning to read in a transparent orthography (Dutch). In addition, we tested the effect of the use of text-to-speech software, a new form of direct instruction, on orthographic learning. Both research goals were investigated by replicating Share’s self-teaching paradigm. A total of 65 disabled Dutch readers were asked to read eight stories containing embedded homophonic pseudoword targets (e.g., Blot/Blod), with or without the support of text-to-speech software. The amount of orthographic learning was assessed 3 or 7 days later by three measures of orthographic learning. First, the results supported the presence of orthographic learning during independent silent reading by demonstrating that target spellings were correctly identified more often, named more quickly, and spelled more accurately than their homophone foils. Our results support the hypothesis that all readers, even poor readers of transparent orthographies, are capable of developing word-specific knowledge. Second, a negative effect of text-to-speech software on orthographic learning was demonstrated in this study. This negative effect was interpreted as the consequence of passively listening to the auditory presentation of the text. We clarify how these results can be interpreted within current theoretical accounts of orthographic learning and briefly discuss implications for remedial interventions.

A Specific Implicit Sequence Learning Deficit as an Underlying Cause of Dyslexia? Investigating the Role of Attention in Implicit Learning Tasks.

Objective: Recently, a general implicit sequence learning deficit was proposed as an underlying cause of dyslexia. This new hypothesis was investigated in the present study by including a number of methodological improvements, for example, the inclusion of appropriate control conditions. The second goal of the study was to explore the role of attentional functioning in implicit and explicit learning tasks. Method: In a 2 × 2 within-subjects design 4 tasks were administered in 30 dyslexic and 38 control children: an implicit and explicit serial reaction time (RT) task and an implicit and explicit contextual cueing task. Attentional functioning was also administered. The entire learning curves of all tasks were analyzed using latent growth curve modeling in order to compare performances between groups and to examine the role of attentional functioning on the learning curves. Results: The amount of implicit learning was similar for both groups. However, the dyslexic group showed slower RTs throughout the entire task. This group difference reduced and became nonsignificant after controlling for attentional functioning. Both implicit learning tasks, but none of the explicit learning tasks, were significantly affected by attentional functioning. Conclusions: Dyslexic children do not suffer from a specific implicit sequence learning deficit. The slower RTs of the dyslexic children throughout the entire implicit sequence learning process are caused by their comorbid attention problems and overall slowness. A key finding of the present study is that, in contrast to what was assumed for a long time, implicit learning relies on attentional resources, perhaps even more than explicit learning does.

Will the Real Discrepant Learning Disability Please Stand Up

Willson and Reynolds (in this issue) challenged my thesis that the regression-based discrepancy method (RDM) is not a valid tool to detect aptitude-achievement discrepancies. In this response, I show that the statistical and theoretical counterarguments of Willson and Reynolds are based on a misreading of the statistical models presented. Furthermore, I demonstrate that the regression adjustment, which is largest for lower correlations, is the direct source of the lack of validity of the RDM procedure. Nevertheless, RDM can be considered a valid method to measure an achievement component that is unrelated to intelligence.Willson and Reynolds (in this issue) challenged my thesis that the regression-based discrepancy method (RDM) is not a valid tool to detect aptitude-achievement discrepancies. In this response, I show that the statistical and theoretical counterarguments of Willson and Reynolds are based on a misreading of the statistical models presented. Furthermore, I demonstrate that the regression adjustment, which is largest for lower correlations, is the direct source of the lack of validity of the RDM procedure. Nevertheless, RDM can be considered a valid method to measure an achievement component that is unrelated to intelligence.