Petroula Mousikou

Common Patterns of Prediction of Literacy Development in Different Alphabetic Orthographies

Previous studies have shown that phoneme awareness, letter-sound knowledge, rapid automatized naming (RAN), and verbal memory span are reliable correlates of learning to read in English. However, the extent to which these different predictors have the same relative importance in different languages remains uncertain. In this article, we present the results from a 10-month longitudinal study that began just before or soon after the start of formal literacy instruction in four languages (English, Spanish, Slovak, and Czech). Longitudinal path analyses showed that phoneme awareness, letter-sound knowledge, and RAN (but not verbal memory span) measured at the onset of literacy instruction were reliable predictors, with similar relative importance, of later reading and spelling skills across the four languages. These data support the suggestion that in all alphabetic orthographies, phoneme awareness, letter-sound knowledge, and RAN may tap cognitive processes that are important for learning to read.

Validation of the Emotiv EPOC® EEG gaming system for measuring research quality auditory ERPs

Background. Auditory event-related potentials (ERPs) have proved useful in investigating the role of auditory processing in cognitive disorders such as developmental dyslexia, specific language impairment (SLI), attention deficit hyperactivity disorder (ADHD), schizophrenia, and autism. However, laboratory recordings of auditory ERPs can be lengthy, uncomfortable, or threatening for some participants – particularly children. Recently, a commercial gaming electroencephalography (EEG) system has been developed that is portable, inexpensive, and easy to set up. In this study we tested if auditory ERPs measured using a gaming EEG system (Emotiv EPOC®, www.emotiv.com) were equivalent to those measured by a widely-used, laboratory-based, research EEG system (Neuroscan). Methods. We simultaneously recorded EEGs with the research and gaming EEG systems, whilst presenting 21 adults with 566 standard (1000 Hz) and 100 deviant (1200 Hz) tones under passive (non-attended) and active (attended) conditions. The onset of each tone was marked in the EEGs using a parallel port pulse (Neuroscan) or a stimulus-generated electrical pulse injected into the O1 and O2 channels (Emotiv EPOC®). These markers were used to calculate research and gaming EEG system late auditory ERPs (P1, N1, P2, N2, and P3 peaks) and the mismatch negativity (MMN) in active and passive listening conditions for each participant. Results. Analyses were restricted to frontal sites as these are most commonly reported in auditory ERP research. Intra-class correlations (ICCs) indicated that the morphology of the research and gaming EEG system late auditory ERP waveforms were similar across all participants, but that the research and gaming EEG system MMN waveforms were only similar for participants with non-noisy MMN waveforms (N = 11 out of 21). Peak amplitude and latency measures revealed no significant differences between the size or the timing of the auditory P1, N1, P2, N2, P3, and MMN peaks. Conclusions. Our findings suggest that the gaming EEG system may prove a valid alternative to laboratory ERP systems for recording reliable late auditory ERPs (P1, N1, P2, N2, and the P3) over the frontal cortices. In the future, the gaming EEG system may also prove useful for measuring less reliable ERPs, such as the MMN, if the reliability of such ERPs can be boosted to the same level as late auditory ERPs.

Can the dual-route cascaded computational model of reading offer a valid account of the masked onset priming effect?

The masked onset priming effect (MOPE) refers to the empirical finding that target naming is faster when the target (SIB) is preceded by a briefly presented masked prime that starts with the same letter/phoneme (suf) than when it does not (mof; Kinoshita, 2000, Experiment 1). The dual-route cascaded (DRC) computational model of reading (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001) has offered an explanation for how the MOPE might occur in humans. However, there has been some empirical discrepancy regarding whether for nonword items the effect is limited to the first-letter/phoneme overlap between primes and targets or whether orthographic/phonological priming effects occur beyond the first letter/phoneme. Experiment 1 tested these two possibilities. The human results, which were successfully simulated by the DRC model, showed priming beyond the first letter/phoneme. Nevertheless, two recent versions of the DRC model made different predictions regarding the nature of these priming effects. Experiment 2 examined whether it is facilitatory, inhibitory, or both, in order to adjudicate between the two versions of the model. The human results showed that primes exert both facilitatory and inhibitory effects.

Is the orthographic/phonological onset a single unit in reading aloud?

Two main theories of visual word recognition have been developed regarding the way orthographic units in printed words map onto phonological units in spoken words. One theory suggests that a string of single letters or letter clusters corresponds to a string of phonemes (Coltheart, 1978; Venezky, 1970), while the other suggests that a string of single letters or letter clusters corresponds to coarser phonological units, for example, onsets and rimes (Treiman & Chafetz, 1987). These theoretical assumptions were critical for the development of coding schemes in prominent computational models of word recognition and reading aloud. In a reading-aloud study, we tested whether the human reading system represents the orthographic/phonological onset of printed words and nonwords as single units or as separate letters/phonemes. Our results, which favored a letter and not an onset-coding scheme, were successfully simulated by the dual-route cascaded (DRC) model (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). A separate experiment was carried out to further adjudicate between 2 versions of the DRC model.

A letter visual-similarity matrix for Latin-based alphabets

Indicators of letter visual similarity have been used for controlling the design of empirical and neuropsychological studies and for rigorously determining the factors that underlie reading ability and literacy acquisition. Additionally, these letter similarity/confusability matrices have been useful for studies examining more general aspects of human cognition, such as perception. Despite many letter visual-similarity matrices being available, they all have two serious limitations if they are to be used by researchers in the reading domain: (1) They have been constructed using atypical reading data obtained from speeded reading-aloud tasks and/or under degraded presentation conditions; (2) they only include letters from the English alphabet. Although some letter visual-similarity matrices have been constructed using data gathered from normal reading conditions, these either are based on old fonts, which may not resemble the letters found in modern print, or were never published. For the first time, this article presents a comprehensive letter visual-similarity/confusability matrix that has been constructed based on untimed responses to clearly presented upper- and lowercase letters that are present in many languages that use Latin-based alphabets, including Catalan, Dutch, English, French, Galician, German, Italian, Portuguese, and Spanish. Such a matrix will be useful for researchers interested in the processes underpinning reading and literacy acquisition.

Computational modelling of the masked onset priming effect in reading aloud

The masked onset priming effect (MOPE) was first defined by Forster and Davis (1991) as the finding that human naming latencies are faster when a target word (e.g., BREAK) is preceded by a briefly presented masked prime word that shares its initial sound with the target (e.g., belly) compared to when it does not (e.g., merry) or when it rhymes with it (e.g., stake). The present paper presents a review of empirical findings on the MOPE in the English language and their simulations by the DRC computational model of reading (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001), which offers an explicit account of how the effect might occur in humans. A new version of DRC, called DRC 1.2, which differs from the previous downloadable DRC version mainly in the way its nonlexical route operates, has been recently developed. The performance of DRC 1.2 on simulating the MOPE is evaluated in this paper.

Lexical frequency effects on articulation: a comparison of picture naming and reading aloud

The present study investigated whether lexical frequency, a variable that is known to affect the time taken to utter a verbal response, may also influence articulation. Pairs of words that differed in terms of their relative frequency, but were matched on their onset, vowel, and number of phonemes (e.g., map vs. mat, where the former is more frequent than the latter) were used in a picture naming and a reading aloud task. Low-frequency items yielded slower response latencies than high-frequency items in both tasks, with the frequency effect being significantly larger in picture naming compared to reading aloud. Also, initial-phoneme durations were longer for low-frequency items than for high-frequency items. The frequency effect on initial-phoneme durations was slightly more prominent in picture naming than in reading aloud, yet its size was very small, thus preventing us from concluding that lexical frequency exerts an influence on articulation. Additionally, initial-phoneme and whole-word durations were significantly longer in reading aloud compared to picture naming. We discuss our findings in the context of current theories of reading aloud and speech production, and the approaches they adopt in relation to the nature of information flow (staged vs. cascaded) between cognitive and articulatory levels of processing.

Masked Primes Activate Feature Representations in Reading Aloud

Theories of reading aloud are silent about the role of subphonemic/subsegmental representations in translating print to sound. However, there is empirical evidence suggesting that feature representations are activated in speech production and visual word recognition. In the present study, we sought to determine whether masked primes activate feature representations in reading aloud using a variation of the masked onset priming effect (MOPE). We found that target nonwords (e.g., BAF) were read aloud faster when preceded by masked nonword primes that shared their initial phoneme with the target (e.g., bez), or primes whose initial phoneme shared all features except voicing with the first phoneme of the target (e.g., piz), compared with unrelated primes (e.g., suz). We obtained the same result in 2 experiments that used different participants and prime durations (around 60 ms in Experiment 1 and 50 ms in Experiment 2). The significant masked feature priming effect that was observed in both experiments converges with the empirical evidence in the speech production and visual word recognition domains indicating a functional role for features in reading aloud. Our findings motivate the further development of current theories of reading aloud and have important implications for extant theories of speech production.

Cues to stress assignment in reading aloud

Research seeking to uncover the mechanisms by which we read aloud has focused almost exclusively on monosyllabic items presented in isolation. Consequently, important challenges that arise when considering polysyllabic word reading, such as stress assignment, have been ignored, while little is known about how important sentence-level stress cues, such as syntax and rhythm, may influence word reading aloud processes. The present study seeks to fill these gaps in the literature by (a) documenting the individual influences of major sublexical cues that readers use to assign stress in single-word reading in English and (b) determining how these cues may interact with contextual stress factors in sentence reading. In Experiments 1, 2, and 3 we investigated the effects of prefixation, orthographic weight (i.e., number of letters in a syllable), and vowel length on stress assignment by asking participants to read aloud carefully-constructed nonwords that varied on the presence of these cues. Results revealed individual effects of all three cues on the assignment of second-syllable stress. In Experiment 4, we tested the effects of these cues on stress assignment in the context of sentence reading. Results showed that sublexical cues influenced stress assignment over and above higher-level syntactic and rhythmic cues. We consider these findings in the framework of extant rule-based, distributed-connectionist, and Bayesian approaches to stress assignment in reading aloud, and we discuss their applications to understanding reading development and acquired and developmental reading disorders.

The Locus of Serial Processing in Reading Aloud: Orthography-to-Phonology Computation or Speech Planning?

Dual-route theories of reading posit that a sublexical reading mechanism that operates serially and from left to right is involved in the orthography-to-phonology computation. These theories attribute the masked onset priming effect (MOPE) and the phonological Stroop effect (PSE) to the serial left-to-right operation of this mechanism. However, both effects may arise during speech planning, in the phonological encoding process, which also occurs serially and from left to right. In the present paper, we sought to determine the locus of serial processing in reading aloud by testing the contrasting predictions that the dual-route and speech planning accounts make in relation to the MOPE and the PSE. The results from three experiments that used the MOPE and the PSE paradigms in English are inconsistent with the idea that these effects arise during speech planning, and consistent with the claim that a sublexical serially operating reading mechanism is involved in the print-to-sound translation. Simulations of the empirical data on the MOPE with the dual route cascaded (DRC) and connectionist dual process (CDP++) models, which are computational implementations of the dual-route theory of reading, provide further support for the dual-route account.