Zihin ve beyin araştırmaları: İkinci dilde biçimbilimsel hazırlamanın davranışsal ve sinirbilimsel değerlendirilmesi

The main goal of this thesis was to investigate the temporal and spatial properties of early morphological processing in a second language (L2). For this purpose, a computer-based masked-priming lexical decision task was implemented, which was followed by a functional magnetic resonance imaging (fMRI) experiment with minimal differences in the data collection procedure. The first experiment was completed by 122 L2 learners of English (L1: Turkish) and the participants of the fMRI study were a subgroup of the former experiment (n. 49). Additionally, in order to test whether L2 early morphological processing was modulated by individual differences, a series of tasks was administered at the end of the first experiment to classify participants according to their level of overall proficiency, spelling accuracy and vocabulary size. The results exhibited a morpho-orthographic decomposition pattern in L2 similar to the findings of the L1 literature. Overall proficiency was also found to be among the determining factors of visual word recognition in L2. As for the analyses of the fMRI data; unlike the L1 literature, left-frontal areas (BA6) were observed to be activated only in the processing of lexical items with links in the surface form but not in the meaning-based associations between primes and targets. Behavioral results laid emphasis on the significant effect of frequency and proficiency on the early stages of morphological processing. On the other hand, neural findings of this thesis referred to the hemodynamic reflections in L2 on the basis of the distinctive properties of morpheme types.