Search

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cogpsych.2006.07.003 Byline: Athanassios Protopapas (a), Anastasia Archonti (b), Christos Skaloumbakas (c) Keywords: Stroop effect; Reading; Automaticity; Dyslexia; Computational modeling Abstract: Stroop interference is often taken as evidence for reading automaticity even though young and poor readers, who presumably lack reading automaticity, present strong interference. Here the relationship between reading skills and Stroop interference was studied in a 7th-grade sample. Greater interference was observed in children diagnosed with reading disability (dyslexia) than in unimpaired children. Moreover, poorer reading skills were found to correlate with greater Stroop interference in the general school population. In correlation and regression analyses, interference was primarily associated with reading speed, with an additional unique contribution of reading accuracy. Color naming errors were few and not comparably related to reading skills. The relation of reading skill to Stroop interference was examined in computational modeling simulations. The production model of Roelofs [Roelofs, A. (2003). Goal-referenced selection of verbal action: modeling attentional control in the Stroop task. Psychological Review, 110, 88-125], in which interference is primarily due to word stimuli having direct access to word form encoding whereas color naming must pass through concept activation and lemma selection, was found to account well for the human data after imposing covariation constraints on parameters controlling word processing and blocking latency, in modifications not affecting the model's previous fit to other data. The connectionist model of Cohen, Dunbar, and McClelland [Cohen, J. D., Dunbar, K., & McClelland, J. L. (1990). On the control of automatic processes: a parallel distributed processing account of the Stroop effect. Psychological Review, 97, 332-361], in which interference is caused by differential route strength, implementing an automaticity account, approximated the observed patterns with network-wide parameter manipulations not specific to reading, such as processing speed and response threshold, likely to affect previously optimized performance. On the basis of the empirical and modeling data we argue for a direct link between reading skill and interference, beyond the effects of executive functioning. Author Affiliation: (a) Institute for Language and Speech Processing/Athena, Artemidos 6 & Epidavrou, GR-15125 Maroussi, Greece (b) Panteion University, Greece (c) Children's Psychiatric Hospital of Attiki, Greece Article History: Accepted 21 July 2006 Article Note: (footnote) [star] We are grateful to A. Roelofs for providing code implementing his model and for his helpful comments. We also thank T. Carr for substantial editorial guidance, E. Altmann for help with the modeling literature, and R. Poldrack for comments on a previous version of this manuscript.

Abstract. Attempts to evaluate the cognitive-motivational profiles of students with reading comprehension difficulties have been scarce. The purpose of the present study was twofold: (a) to assess the discriminatory validity [...]

Exposure to modified speech has been shown to benefit children with language-learning impairments with respect to their language skills (M. M. Merzenich et al., 1998; P. Tallal et al., 1996). In the study by Tallal and colleagues, the speech modification consisted of both slowing down and amplifying fast, transitional elements of speech. In this study, we examined whether the benefits of modified speech could be extended to provide intelligibility improvements for children with severe-to-profound hearing impairment who wear sensory aids. In addition, the separate effects on intelligibility of slowing down and amplifying speech were evaluated. Two groups of listeners were employed: 8 severe-to-profoundly hearing-impaired children and 5 children with normal hearing. Four speech-processing conditions were tested: (1) natural, unprocessed speech; (2) envelope-amplified speech; (3) slowed speech; and (4) both slowed and envelope-amplified speech. For each condition, three types of speech materials were used: words in sentences, isolated words, and syllable contrasts. To degrade the performance of the normal-hearing children, all testing was completed with a noise background. Results from the hearing-impaired children showed that all varieties of modified speech yielded either equivalent or poorer intelligibility than unprocessed speech. For words in sentences and isolated words, the slowing-down of speech had no effect on intelligibility scores whereas envelope amplification, both alone and combined with slowing-down, yielded significantly lower scores. Intelligibility results from normal-hearing children listening in noise were somewhat similar to those from hearing-impaired children. For isolated words, the slowing-down of speech had no effect on intelligibility whereas envelope amplification degraded intelligibility. For both subject groups, speech processing had no statistically significant effect on syllable discrimination. In summary, without extensive exposure to the speech processing conditions, children with impaired hearing and children with normal hearing listening in noise received no intelligibility advantage from either slowed speech or envelope-amplified speech. KEY WORDS: speech perception, hearing-impaired listeners, lime-expansion of speech, envelope modification of speech, At oral schools for the deaf, such as Central Institute for the Deaf (CID), there is an obvious, critical need for speech to be delivered more intelligibly to children with [...]

Speech comprehension depends on the integrity of both the spectral content and temporal envelope of the speech signal. Although neural processing underlying spectral analysis has been intensively studied, less is known about the processing of temporal information. Most of speech information conveyed by the temporal envelope is confined to frequencies below 16 Hz, frequencies that roughly match spontaneous and evoked modulation rates of primary auditory cortex neurons. To test the importance of cortical modulation rates for speech processing, we manipulated the frequency of the temporal envelope of speech sentences and tested the effect on both speech comprehension and cortical activity. Magnetoencephalographic signals from the auditory cortices of human subjects were recorded while they were performing a speech comprehension task. The test sentences used in this task were compressed in time. Speech comprehension was degraded when sentence stimuli were presented in more rapid (more compressed) forms. We found that the average comprehension level, at each compression, correlated with (i) the similarity between the frequencies of the temporal envelopes of the stimulus and the subject's cortical activity ('stimulus-cortex frequency-matching') and (ii) the phase-locking (PL) between the two temporal envelopes ('stimulus-cortex PL'). Of these two correlates, PL was significantly more indicative for single-trial success. Our results suggest that the match between the speech rate and the a priori modulation capacities of the auditory cortex is a prerequisite for comprehension. However, this is not sufficient: stimulus-cortex PL should be achieved during actual sentence presentation. human | MEG | time compression | accelerated speech | phase-locking

M. A. Pitt, K. L. Smith, and J. M. Klein (1998) claimed that a baseline condition is necessary in experiments using the structural induction paradigm (S. A. Finney, A. Protopapas, & P. D. Eimas, 1996; C. Pallier, N. Sebastian-Galles, T. Felguera, A. Christophe, & J. Mehler, 1993) to correctly interpret interaction effects. In this article it is shown that this constitutes a misunderstanding of the interpretation of statistical interaction and that a baseline condition offers little unless comparisons between cells of different target types within induction conditions are necessary.

A broad battery of psychoacoustic measures and standard measures of reading and spelling were applied to 102 adults. The test group included individuals with a childhood history of reading difficulties and controls with no reported reading difficulties. Reading scores were variable in both groups. Poor auditory processing abilities were recorded in poor readers; particular difficulties were posed by tasks requiring spectral distinctions, the simplest of which was pure tone frequency discrimination. In absolute terms, the greatest deficits were recorded in tasks in which stimuli were presented in brief forms and in rapid succession. Auditory processing abilities accounted for more than 50% of the reading score variance in the control group, but their correlation with reading scores was lower in the group with childhood histories of reading difficulties. The additional variability in the latter group resulted largely from the prevalence of reading-compensated poor psychoacoustic performers, whose short-term word memory was also typically poor. Taken together, these findings support a link between impaired auditory resolution and poor reading. Psychoacoustic difficulties are largely retained through adulthood and may be the source of the retained reading difficulties.

Connectionist models of perception and cognition, including the process of deducing meaningful messages from patterns of acoustic waves emitted by vocal tracts, are developed and refined as human understanding of brain function, psychological processes, and the properties of massively parallel architectures advances. The present article presents several important contributions from diverse points of view in the area of connectionist modeling of speech perception and discusses their relative merits with respect to specific theoretical issues and empirical findings. TRACE, the Elman/Norris net, and Adaptive Resonance Theory constitute pivotal points exemplifying overall modeling success, progress in temporal representation, and plausible modeling of learning, respectively. Other modeling efforts are presented for the specific insights they offer, and the article concludes with a discussion of computational versus dynamic modeling of phonological processes.

The arguments for the orderly output constraint concern phylogenetic matters and do not address the ontogeny of combination-specific neurons and the corresponding processing mechanisms. Locus equations are too variable to be strongly predetermined and too inconsistent to be easily learned. Findings on the development of speech perception and underlying auditory processing must be taken into account in the formulation of neural encoding theories.

An experimental study involving five men belonging to the 1993 American Sagarmatha expedition to Mount Everest helps understand the effect of altitude on cognitive functions. The experiment proves that the voice onset timing separation width is shorter and that the response time to the difficult items of the Rhode Island test of language structure is longer at higher altitude, showing evidence of a mild anoxia of subcortical circuits to prefrontal cortex. The symptoms are similar to those found in persons with Parkinson's disease and may have been caused by disruption of subcortical basal ganglia pathways to prefrontal cortex.