Document Type


Degree Name

Doctor of Philosophy (PhD)



Program Name/Specialization

Cognitive Neuroscience


Faculty of Science

First Advisor

Jeffery A. Jones

Advisor Role

Thesis advisor


The purpose of this dissertation was to examine the contribution of phonological overlap to visual word recognition. More specifically, this study aimed at testing the phonological account of the cognate effect (i.e., faster and more accurate mental processing of cognates than noncognates) in visual word recognition in Persian and English, which are languages with different scripts. The phonological account attributes the cognate effect to the phonological similarity of cognates (form and semantically related words) in addition to the conceptual similarity that cognates and noncognates (semantically related words) have and to the degree of phonological similarity between cognates in two languages. Thus, the phonological account predicts that the size of the cognate effect correlates with the phonological similarity of cognates and the lack of this feature in noncognates. Another objective of this study was to examine and confirm the nonselectivity view of bilingual word recognition in late but proficient Persian-English bilinguals, which holds that bilinguals cannot avoid the nontarget language when reading in one language. Also, this study aimed to investigate whether the effect of the nontarget language, if any, would start earlier when the languages have different rather than similar scripts. This dissertation comprises three studies. In the first study (Chapter 2) a database was created that included the stimuli used in subsequent studies. Lexico-semantic features of the stimuli in the database were examined to determine the importance of these features in Persian and English. The second (Chapter 3) and third (Chapter 4) studies used a masked priming lexical decision task to collect response time (RT), accuracy, and event-related potentials (ERPs) to assess whether the Persian-English (Chapter 3) and English-Persian (Chapter 4) direction affected the processing of cognates and noncognates. A within-subjects analysis of variance supported the importance of high phonological similarity in visual word recognition in Persian-English bilinguals who know two different-script languages, as cognates with lower phonological similarity showed inconsistent effects and noncognates failed to show any priming effects in either direction in the experiments. Cognates with high phonological similarity were processed faster in both Persian and English and produced more correct responses in English. Finally, the event-related potential (ERP) analysis showed that high phonological similarity elicited a P100 in English and a smaller N150 in Persian. A better understanding of bilingual word recognition has theoretical implications for models of bilingual word processing and practical implications for language teaching, especially when the words have similarities in the first and the second language.

Convocation Year


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