Robin L. Peterson

Lexical Selection Is Not by Competition: A Reinterpretation of Semantic Interference and Facilitation Effects in the Picture-Word Interference Paradigm

The dominant view in the field of lexical access in speech production maintains that selection of a word becomes more difficult as the levels of activation of nontarget words increase--selection by competition. The authors tested this prediction in two sets of experiments. First, the authors show that participants are faster to name pictures of objects (e.g., bed) in the context of semantically related verb distractors (e.g., sleep) compared with unrelated verb distractors (e.g., shoot). In the second set of experiments, the authors show that target naming latencies (e.g., horse) are, if anything, faster for within--category semantically close distractor words (e.g., zebra) than for within--category semantically far distractor words (e.g., whale). In the context of previous research, these data ground a new empirical generalization: As distractor words become semantically closer to the target concepts--all else being equal--target naming is facilitated. This fact means that lexical selection does not involve competition, and consequently, that the semantic interference effect does not reflect a lexical level process. This conclusion has important implications for models of lexical access and interpretations of Stroop-like interference effects.

Seminar: Developmental Dyslexia

Dyslexia is a neurodevelopmental disorder that is characterised by slow and inaccurate word recognition. Dyslexia has been reported in every culture studied, and mounting evidence draws attention to cross-linguistic similarity in its neurobiological and neurocognitive bases. Much progress has been made across research specialties spanning the behavioural, neuropsychological, neurobiological, and causal levels of analysis in the past 5 years. From a neuropsychological perspective, the phonological theory remains the most compelling, although phonological problems also interact with other cognitive risk factors. Work confirms that, neurobiologically, dyslexia is characterised by dysfunction of the normal left hemisphere language network and also implicates abnormal white matter development. Studies accounting for reading experience demonstrate that many recorded neural differences show causes rather than effects of dyslexia. Six predisposing candidate genes have been identified, and evidence shows gene by environment interaction.

Subtypes of developmental dyslexia: testing the predictions of the dual-route and connectionist frameworks.

We investigated the phonological and surface subtypes of developmental dyslexia in light of competing predictions made by two computational models of single word reading, the Dual-Route Cascaded Model (DRC; Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001) and Harm and Seidenbergs connectionist model (HS model; Harm & Seidenberg, 1999). The regression-outlier procedure was applied to a large sample to identify children with disproportionately poor phonological coding skills (phonological dyslexia) or disproportionately poor orthographic coding skills (surface dyslexia). Consistent with the predictions of the HS model, children with pure phonological dyslexia, who did not have orthographic deficits, had milder phonological impairments than children with relative phonological dyslexia, who did have secondary orthographic deficits. In addition, pure cases of dyslexia were more common among older children. Consistent with the predictions of the DRC model, surface dyslexia was not well conceptualized as a reading delay; both phonological and surface dyslexia were associated with patterns of developmental deviance. In addition, some results were problematic for both models. We identified a small number of individuals with severe phonological dyslexia, relatively intact orthographic coding skills, and very poor real word reading. Further, a subset of controls could read normally despite impaired orthographic coding. The findings are discussed in terms of improvements to both models that might help better account for all cases of developmental dyslexia.

Statistical Learning, Letter Reversals, and Reading.

Reversal errors play a prominent role in theories of reading disability. We examined reversal errors in the writing of letters by 5- to 6-year-old children. Of the 130 children, 92 had a history of difficulty in producing speech sounds, a risk factor for reading problems. Children were more likely to reverse letter forms that face left, such as and , than forms that face right, such as and . We propose that this asymmetry reflects statistical learning: Children implicitly learn that the right-facing pattern is more typical of Latin letters. The degree of asymmetry that a child showed was not related to the child’s reading skill at Time 2, 2¾ years later. Although children who went on to become poorer readers made more errors in the letter writing task than children who went on to become better readers, they were no more likely to make reversal errors.

Adolescents' internalizing problems following traumatic brain injury are related to parents' psychiatric symptoms

Background:A small body of previous research has demonstrated that pediatric traumatic brain injury (TBI) increases risk for internalizing problems, but findings have varied regarding their predictors and correlates. Methods:We examined the level and correlates of internalizing symptoms in 130 teens who had sustained a complicated mild to severe TBI within the past 1 to 6 months. Internalizing problems were measured via both maternal- and paternal-report Child Behavior Checklist. We also measured family functioning, parent psychiatric symptoms, and postinjury teen neurocognitive function. Results:Mean parental ratings of internalizing problems were within the normal range. Depending on informant, 22% to 26% of the sample demonstrated clinically elevated internalizing problems. In multiple and binary logistic regression models, only parent psychiatric symptoms consistently provided unique prediction of teen internalizing symptoms. For maternal but not paternal report, female gender was associated with greater internalizing problems. Conclusion:Parent and teen emotional problems are associated following adolescent TBI. Possible reasons for this relationship, including the effects of TBI on the family unit, are discussed.

Longitudinal Stability of Phonological and Surface Subtypes of Developmental Dyslexia

Limited evidence supports the external validity of the distinction between developmental phonological and surface dyslexia. We previously identified children ages 8 to 13 meeting criteria for these subtypes (Peterson, Pennington, & Olson, 2013) and now report on their reading and related skills approximately 5 years later. Longitudinal stability of subtype membership was fair and appeared stronger for phonological than surface dyslexia. Phonological dyslexia was associated with a pronounced phonological awareness deficit, but subgroups otherwise had similar cognitive profiles. Subtype did not inform prognosis. Results provide modest evidence for the validity of the distinction, although not for its clinical utility.

The Development of Global and Local Processing: A Comparison of Children to Adults.

In light of the adult model of a hemispheric asymmetry of global and local processing, we compared children (M age = 8.4 years) to adults in a global-local reaction time (RT) paradigm. Hierarchical designs (large shapes made of small shapes) were presented randomly to each visual field, and participants were instructed to identify either the global or the local level in each of two blocks. We obtained evidence of a global-local processing asymmetry, with stronger effects for children than for adults. In both children and adults, responses were faster and more accurate for global identification in the right hemisphere and for local identification in the left hemisphere. Similarly, a significant asymmetry of global and local interference was obtained in children but not in adults. Interference reflects the RT cost of conflicting information at the nonattended level. For example, local interference indicates the degree to which inconsistency at the local level slows global identification. Stronger evidence for lateralized processing in children is discussed within the framework of increasing interhemispheric transfer. That is, as interhemispheric transfer increases, cost of presentation to the nonpreferred hemisphere (e.g., local identification in the right hemisphere) is reduced.

An Essential Neuroanatomy Reference: Thoroughly Updated But Not Exactly Revised

In 2002, Hal Blumenfeld published the first edition of Neuroanatomy Through Clinical Cases. Both the erudition and the sheer effort reflected in this comprehensive text are suggestive of a professor who is at once a scientist, a clinician, and a deeply committed teacher. It is easy to imagine that Blumenfeld spent countless hours in medical school classrooms conveying the information that would eventually be organized into the impressive volume. As a testament to both the author’s accomplishment and the rising interdisciplinary demand for accessible, authoritative sources in the neurosciences, students and practitioners across a range of fields soon adopted the text. In the neuropsychology community today, Blumenfeld’s text is considered to be one of the finest neuroanatomy volumes available, widely recognized as an invaluable everyday reference, teaching tool, and board examination resource. In 2002, reviewers praised the clarity of writing, organization, extensive illustrations, tables, and imaging examples, all of which have been preserved or improved in the second edition. In both editions, key terms and concepts are clearly delineated through the use of boldface type and headers. Helpful mnemonics (e.g., HEAL to remember the hypothalamic functions of Homeostatic mechanisms, Endocrine control, Autonomic control, and Limbic mechanisms), typically several per chapter, are marked with an icon depicting the hippocampus. Each chapter also contains several interactive review exercises designed to support learning of the dense, detailed information included in the now more than 1000-page text. Supplemental on-line information available at no extra change