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According to the Simple View of Reading (SVR; Gough & Tunmer, 1986; Hoover & Gough, 1991), all variation in reading can be accounted for by two component skills; decoding and language comprehension. However, these skills also need to be considered in the context of orthography. Languages differ considerably in terms of their orthographic structure; inconsistent orthographies have an inconsistent grapheme-phoneme conversion, like that of English, and consistent orthographies consist of a consistent conversion, like that of Italian or Spanish. The Orthographic Depth Hypothesis (Katz & Frost, 1992) claims that efficient reading requires readers to adapt reading strategies to meet the demands of the orthography being read. Languages with varying depths of orthographies may require distinct reading strategies that drive the development of specific reading skills and may affect a bilingual's ability to efficiently comprehend texts in languages of varying orthographic depths. Further, inconsistent orthographies may place higher demands on word reading than consistent orthographies. According to the Hypothesis of Granularity and Transparency (Wydell & Butterworth, 1999), orthography can be broken down into two main features that may be responsible for incidences of phonological dyslexia; 'transparency' and 'granularity'. The HGT argues that transparent languages will yield fewer instances of phonological dyslexia than opaque orthographies. However, even in opaque orthographies, if the smallest graphemic unit representing sound is equal to a whole character or a whole word (i.e., coarse grain), as opposed to a syllable or phoneme (i.e., fine grain), it will not produce a high prevalence of phonological dyslexia. English dyslexics are known to have poor decoding skills, which may cause them to engage in compensatory eye-movement patterns during reading. The current experiment used eye-tracking techniques to compare reading strategies in three groups: native-English monolingual readers with and without developmental dyslexia (DD) and Spanish-English bilinguals reading in both their native and second language.

The primary focus of the current research program concerns visual word recognition and reading aloud as a function of orthographic transparency to inform current debates about the nature of visual word recognition. Within this thesis, this topic is explored using several different approaches with Turkish as the medium of choice. Additionally, the extreme orthographic transparency of Turkish serves as an excellent medium to test theories of visual word recognition. Any universal framework would need to account for the variation found in the writing systems of the Turkic family. Using a computational linguistic method, Chapter 2 explores current definitions of orthographic transparency and novel means of quantifying orthography, extending this approach to Turkish. The result was the production of four language models that take into account the different phoneme inventories used in Turkish, as well as the two main strategies (Word-onset vs whole-word), employed to investigate the quantification of Turkish. The models produced stipulate that Turkish is more transparent than any other alphabetic orthography that has been quantified to date. The chapter also highlights the superiority of whole-word approaches in capturing a full range of variation within an orthography despite some of the current cross-linguistic limitations of using such a method. Chapter 3 examines the currently available resources for Turkish psycholinguistic research and in response to the discovery of a lack of resources in the domain, has led to the creation of the Turkish Lexicon database. The new resource is a sizeable psycholinguistic database that includes several measures of word frequency, contextual diversity and orthographic neighbourhood density as well as providing lexical information such as word and syllable length, bigram and trigram frequency. The Turkish Lexicon was validated using a lexical decision task and also produced a subcorpus for use in future psycholinguistic studies with children. Furthermore, there has been hardly any empirical research investigating linguistic, metalinguistic, and cognitive processes involved in reading the highly transparent orthography of Turkish. To address this, Chapters 4 and 5 investigate how these skills might impact Turkish children who are learning to read and also aims to uncover how developmental dyslexia might manifest itself in Turkish. As such, the current research has the potential to add to our understanding of the cognitive mechanisms that underlie reading in alphabetic languages. It is envisaged that the findings of this study will add to the current debate concerning the distinct influence of universal principles and specific variations in writing systems on cognitive reading processes. In addition, the research will provide conceivably the most comprehensive account of typical and atypical reading development in Turkish-speaking children to date which has huge potential practical implications. Chapter 4 examines the reading strategies of monolingual Turkish schoolchildren while they completed both a single-word naming and oral reading fluency task amongst a battery of cognitive tasks. The findings of the rapid development of phonology as well as the use of two distinct strategies in single-word reading lend support to the weak versions of the phonological and orthographic depth hypothesis of reading. Chapter 5 continues to pursue this question by examining reading disorder, i.e., Developmental Dyslexia in Turkish children. According to Wydell and Butterworth's (1999) Hypothesis of Transparency and Granularity, transparent orthographies such as Turkish should not manifest with a high incidence of phonological dyslexia. The findings of Chapter 5 lend support to this position as well as being in line with multiple deficit models of dyslexia (Pennington, 2006). In Chapter 6, the behavioural data of this doctoral thesis is supplemented with the development of a computational model of visual word recognition in Turkish, the first of its kind. The model builds on the recent incorporation of a self-teaching algorithm (Pritchard, 2012) in the Dual Route Cascaded model of reading aloud and word recognition (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). Simulations include exposing the model to vocabularies of varying size to simulate different stages of vocabulary growth in reading development. In addition, Chapter 6 took preliminary steps in investigating the manifestation of developmental dyslexia in Turkish from a computational perspective.

Objective: This study aims to explore the traumatic experiences and to estimate prevalence and predictor factors for PTSD, depression and general psychiatric morbidity amongst Palestinian adults living in the Gaza Strip. Method: A total of 500 Palestinian adults were recruited from four areas of the Gaza Strip using a snowball sampling. The same sample was used for both quantitative studies. Four scales were employed to identify predictors for trauma, PTSD, depression and general mental health. Participants were divided into three age groups: young adults (18 to 25 years), adults (26 to 49 years) and older adults (50 to 65 years). The third qualitative study was aimed at exploring the traumatic experiences of adults living in the Gaza Strip to expand upon the outcomes from the quantitative studies. Results: For Studies 1 and 2, the prevalence rate of PTSD symptoms was 90% and 36.7% met the criteria of DSM-IV for PTSD. Study 2 found depression was 38.4%, and general mental health comorbidity was 67.1%. Study 2 revealed significant differences in PTSD between age groups. Novel results were found amongst adults and older adults on the re-experiencing subscale for PTSD. Participants who lived in Gaza City scored significantly higher on the PTSD subscale for hyperarousal compared to those living in the middle Gaza region. Study 3 expanded on the psychometric data through interviewing members of the Gaza community. When analysed five main themes were identified: Siege related stressors; war related trauma; psychological negative effects; re-experiencing initial event and coping strategies. Conclusions: The findings indicated that blockade was the predominant cause of the increased prevalence rate of PTSD. These studies found that the Palestinian adult participants in Gaza had been exposed to a variety of traumatic events on an ongoing basis that was having a detrimental impact on their mental health.

The aim of this thesis was to better understand English as second language Nigerian children’s reading comprehension attainment, the first such study to be conducted in Nigeria. In the thesis three studies were conducted to investigate the influence of cognitive and decoding/reading skills on the children’s reading comprehension attainment, namely the preliminary study (Chapter-3) with one primary school in Nigeria, the main study (Chapter-4) with 13 state-run primary schools, and the control study (Chapter-5) including four primary schools in London, respectively. It was found that English as second language children’s reading comprehension performance is significantly influenced by cognitive, decoding and chronological age. The development of cognitive skills which is necessary for success in reading comprehension development is also dependent upon chronological age. That is, age-related increase in cognitive skills brings about increased engagement and more efficient reading comprehension attainment in the children. The normal cognitive development of the children had a positive role also on the children’s performance on language tests necessary for text comprehension. The study found that school socioeconomic background played a significant impact in the performance of Nigerian English as second language children – the better the socioeconomic background of the school the higher the reading comprehension attainment of the children. Furthermore gender was not a factor in the performance and development of reading comprehension by English as Second Language Nigerian children. This implies that parents, teachers and schools motivate and support children irrespective of being boys or girls to realise their full potentials without any discrimination. Having reviewed few theories of reading acquisition/development, the Simple view of reading (SVR) was found to be more appropriate for adoption in this study of Nigerian English as second language children’s reading comprehension attainment. The theory postulates that text comprehension is achieved when children have decoding skills and linguistic comprehension knowledge. The results obtained in Chapters 3 and 4 were in line with the Simple view of reading’s assertion – text comprehension depends on decoding and cognitive skills.

At a perceptual level, faces and voices consist of very different sensory inputs and therefore, information processing from one modality can be independent of information processing from another modality (Adolphs & Tranel, 1999). However, there may also be a shared neural emotion network that processes stimuli independent of modality (Peelen, Atkinson, & Vuilleumier, 2010) or emotions may be processed on a more abstract cognitive level, based on meaning rather than on perceptual signals. This thesis therefore aimed to examine emotion recognition across two separate modalities in a within-subject design, including a cognitive Chapter 1 with 45 British adults, a developmental Chapter 2 with 54 British children as well as a cross-cultural Chapter 3 with 98 German and British children, and 78 German and British adults. Intensity ratings as well as choice reaction times and correlations of confusion analyses of emotions across modalities were analysed throughout. Further, an ERP Chapter investigated the time-course of emotion recognition across two modalities. Highly correlated rating profiles of emotions in faces and voices were found which suggests a similarity in emotion recognition across modalities. Emotion recognition in primary-school children improved with age for both modalities although young children relied mainly on faces. British as well as German participants showed comparable patterns for rating basic emotions, but subtle differences were also noted and Germans perceived emotions as less intense than British. Overall, behavioural results reported in the present thesis are consistent with the idea of a general, more abstract level of emotion processing which may act independently of modality. This could be based, for example, on a shared emotion brain network or some more general, higher-level cognitive processes which are activated across a range of modalities. Although emotion recognition abilities are already evident during childhood, this thesis argued for a contribution of ‘nurture’ to emotion mechanisms as recognition was influenced by external factors such as development and culture.

Understanding the process of language acquisition is a challenge that many researchers spanning different disciplines (e.g. linguistics, psychology, neuroscience) have grappled with for centuries. One which has in recent years attracted a lot of attention has been in the area of non-native phoneme acquisition. Speech sounds that contain multiple phonetic cues are often difficult for foreign-language learners, especially if certain cues are weighted differently in the foreign and native languages. Greek adult and child speakers of English were studied to determine which cues (duration or spectral) they were using to make discrimination and identification judgments for an English vowel contrast pair. To this end, two forms of identification and discrimination tasks were used: natural (unedited) stimuli and another ‘modified’ vowel duration stimuli which were edited so that there were no duration differences between the vowels. Results show the Greek speakers were particularly impaired when they were unable to use the duration cue as compared to the native English speakers. Similar results were also obtained in control experiments where there was no orthographic representation or where the stimuli were cross-spliced to modify the phonetic neighborhood. Further experiments used high-variability training sessions to enhance vowel perception. Following training, performance improved for both Greek adult and child groups as revealed by post training tests. However the improvements were most pronounced for the child Greek speaker group. A further study examined the effect of different orthographic cues that might affect rhyme and homophony judgment. The results of that study showed that Greek speakers were in general more affected by orthography and regularity (particularly of the vowel) in making these judgments. This would suggest that Greek speakers were more sensitive to irrelevant orthographic cues, mirroring the results in the auditory modality where they focused on irrelevant acoustic cues. The results are discussed in terms of current theories of language acquisition, with particular reference to acquisition of non-native phonemes.

This thesis examined the cognitive processes and neural correlates involved in reading Spanish (a transparent orthography), English (an intermediate orthography) and Hebrew (an opaque orthography) by bilinguals and trilinguals. The main objectives of the five experiments were to: (i) extend previous findings which demonstrated that orthographic transparency influences the degree of reliance on lexical and sublexical processing, and (ii) assess the effects of orthographic transparency and language proficiency on strategies employed for reading in a second and third language. Word/non-word naming tasks undertaken by Spanish-English bilinguals, Hebrew-English bilinguals and English monolinguals, where frequency, length and lexicality were manipulated, showed a predominant reliance on sublexical processing in Spanish, lexical processing in Hebrew, and a balanced interplay in English. Effects of language proficiency were also observed as slower naming and lower accuracy in English as a second language. Concurrently, while showing an efficient adaptation of reading strategy to the level of orthographic transparency of English, Hebrew bilinguals appeared to show stronger reliance on sublexical processing than Spanish bilinguals, suggesting a compensatory mechanism. fMRI experiments showed that reading in all languages was associated with a common network of predominantly left-lateralised cerebral regions. Reading in each language was associated with some preferential activation within regions implicated in lexical and sublexical processing, in keeping with their graded levels of orthographic transparency. Effects of language proficiency were demonstrated as increased activation within medial frontal regions implicated in attentional processes as well as right-lateralised homologous language-processing regions. Furthermore, the patterns of activation seen in Hebrew readers in English strengthened the notion of a compensatory mechanism. Finally, a trilingual experiment replicated findings observed in bilinguals, revealed the acute complexity of reading in Hebrew as an additional language and further strengthened the concept of a compensatory mechanism in English and Spanish. The present findings further contribute to current knowledge on teaching methods, diagnostic tools and therapeutic strategies for developmental and acquired reading disorders.