The unexplained nature of reading.

The effects of properties of words on their reading aloud response times (RTs) are 1 major source of evidence about the reading process. The precision with which such RTs could potentially be predicted by word properties is critical to evaluate our understanding of reading but is often underestimated due to contamination from individual differences. We estimated this precision without such contamination individually for 4 people who each read 2,820 words 50 times each. These estimates were compared to the precision achieved by a 31-variable regression model that outperforms current cognitive models on variance-explained criteria. Most (around 2/3) of the meaningful (non-first-phoneme, non-noise) word-level variance remained unexplained by this model. Considerable empirical and theoretical-computational effort has been expended on this area of psychology, but the high level of systematic variance remaining unexplained suggests doubts regarding contemporary accounts of the details of the mechanisms of reading at the level of the word. Future assessment of models can take advantage of the availability of our precise participant-level database

Letters in words are read simultaneously, not in left-to-right sequence

The identification of individual letters is necessary for reading words in alphabetic script (Pelli, Farell, & Moore, 2003). Sequential models of letter processing (Whitney, 2001) in reading words posit an initial left-to-right sequence of letter processing (in left-to-right languages, such as English), each letter taking 10–25 ms to process before the next is processed. In contrast, simultaneous models of letter processing (e.g., Tydgat & Grainger, 2009) in reading words posit that information about the identity of each letter starts to be extracted at the same time point, regardless of horizontal position. Here we show that people reading four-letter words do not extract identity information for any letter from an 18 ms display of the word, but some information about all four letters is available from 24 ms of display. Our results indicate that a left-to-right sequence of attention across letters is not used in establishing the cognitive representation of words. Instead, all letters are processed simultaneously

Word naming at the individual level

Megastudies of visual word recognition—assessing large numbers of items averaged over individuals—are increasingly being used to test hypotheses and models. They are useful because they offer a more precise and powerful window onto the relevant cognitive processes than do item-selection designs. However, they are not without limitations, of which some relate to individual differences: Models are not asked to produce the full range of effect sizes produced by participants, and averaged curves do not always reproduce the curves in individual participant data. Models may therefore be asked to produce an (artifactual) functional form that is exhibited by no participant. Here, we present sufficient word naming data on 4 participants who may each be treated as a separate experiment. These data provide (1) evidence for individual differences, which suggests that some effects are not universal, and (2) more stringent R2 targets for models to meet

Individual differences in reading aloud : a mega-study, item effects, and some models

Normal individual differences are rarely considered in the modelling of visual word recognition – with item response time effects and neuropsychological disorders being given more emphasis – but such individual differences can inform and test accounts of the processes of reading. We thus had 100 participants read aloud words selected to assess theoretically important item response time effects on an individual basis. Using two major models of reading aloud – DRC and CDP+ – we estimated numerical parameters to best model each individual’s response times to see if this would allow the models to capture the effects, individual differences in them and the correlations among these individual differences. It did not. We therefore created an alternative model, the DRC-FC, which successfully captured more of the correlations among individual differences, by modifying the locus of the frequency effect. Overall, our analyses indicate that (i) even after accounting for individual differences in general speed, several other individual difference in reading remain significant; and (ii) these individual differences provide critical tests of models of reading aloud. The database thus offers a set of important constraints for future modelling of visual word recognition, and is a step towards integrating such models with other knowledge about individual differences in reading

Warwick oral reading differences project

Neuropsychological and developmental differences in reading have long informed visual word recognition theories. For instance, identification of whole-word readers (i.e., phonological dyslexics, Chinese-style readers) and part-word readers (i.e., surface dyslexics, Phoenician-style readers) has constrained visual word recognition theories. The influence of variability in normal readers’ cognitive abilities on visual word recognition is yet to be explored. Differences in visual and attentional processes, long- and short-term memory, verbal and nonverbal cognitive ability, and auditory and phonological processing could influence lexical processing, which should constrain such theories. We describe the Warwick Oral Reading Differences project, which seeks to relate these factors to the strength of lexical effects on the response times typically observed in normal adult naming experiments (i.e., word frequency, length, neighborhood size, regularity, and consistency) to further constrain the interpretation of these effects and, thus, model development. Findings from the project are presented

Eye Tracking Reveals Impaired Attentional Disengagement Associated with Sensory Response Patterns in Children with Autism

This study used a gap-overlap paradigm to examine the impact of distractor salience and temporal overlap on the ability to disengage and orient attention in 50 children (4–13 years) with ASD, DD and TD, and associations between attention and sensory response patterns. Results revealed impaired disengagement and orienting accuracy in ASD. Disengagement was impaired across all groups during temporal overlap for dynamic stimuli compared to static, but only ASD showed slower disengagement from multimodal relative to unimodal dynamic stimuli. Attentional disengagement had differential associations with distinct sensory response patterns in ASD and DD. Atypical sensory processing and temporal binding appear to be intertwined with development of disengagement in ASD, but longitudinal studies are needed to unravel causal pathways