zohar eviatar | University of Haifa (original) (raw)

Papers by zohar eviatar

Comprehensive Psychiatry, 2011

Objective: To assess the familial influence on neuropsychological dysfunction in eating disorders... more Objective: To assess the familial influence on neuropsychological dysfunction in eating disorders (ED) patients by comparing 16 patients with restricting type anorexia nervosa (AN-R), 18 patients with bingeing purging type anorexia nervosa, 20 patients with bulimia nervosa binge-purge type, 21 of the patients' nonaffected sisters, and 20 nonrelated healthy controls. Methods: Self-report questionnaires assessing psychopathology and 2 computerized cognitive tasks measuring hemispheric asymmetry for language and visuospatial abilities were administered to all participant groups. Results: On the self-report questionnaires, ED patients scored significantly more pathological than the healthy controls, whereas the healthy sisters were similar to the nonrelated healthy control group. For both of the computerized tasks, the behavior pattern of the sisters was similar to that of all, or most ED groups, and were significantly different from the nonrelated healthy controls. In addition, AN-R patients performed significantly worse on the visuospatial task than the other ED groups. Conclusions: The dissociation between the performance on the cognitive tasks and psychopathology measures in healthy sisters, when compared to the ED and nonrelated healthy control groups, suggests that disturbances in neurocognitive functioning in ED patients are not necessarily the result of ED-related dysfunction. Rather, this may indicate general individual differences in cognitive processes that may run in families irrespective of the ED condition of the family member. The findings, with respect to the AN-R patients, support a neurocognitive continuum model of EDs in which AN-R represents the most severe form of the illness.

A model of certain aspects of the cortex related to reading is developed corresponding to ongoing... more A model of certain aspects of the cortex related to reading is developed corresponding to ongoing exploration of psychophysical and computational experiments on how the two hemispheres work in humans. The connectivity arrangements between modelled areas of orthography, phonology and semantics are according to the theories of Eviatar and Peleg, in particular with distinctions between the connectivity in the right and left hemisphere. The two hemispheres are connected and interact both in training and testing in a reasonably "natural" way. We found that the RH (right hemisphere) serves to maintain alternative meanings under this arrangement longer than the LH for homophones. This corresponds to the usual theories (about homographs) while, surprisingly, the LH maintains alternative meanings longer then the RH for heterophones. This allows the two hemispheres, working together to resolve ambiguities regardless of when the disambiguating information arrives. Human experiments c...

Reading and Writing, 2018

Neuropsychology, 2017

Objectives: The current fMRI study examined the role of phonology in the extraction of meaning fr... more Objectives: The current fMRI study examined the role of phonology in the extraction of meaning from print in each hemisphere by comparing homophonic and heterophonic homographs (ambiguous words in which both meanings have the same or different sounds respectively, e.g., bank or tear). The analysis distinguished between the first phase, in which participants read ambiguous words without context, and the second phase in which the context resolves the ambiguity. Method: Native Hebrew readers were scanned during semantic relatedness judgments on pairs of words in which the first word was either a homophone or a heterophone and the second word was related to its dominant or subordinate meaning. Results: In Phase 1 there was greater activation for heterophones in left inferior frontal gyrus (IFG), pars opercularis, and more activation for homophones in bilateral IFG pars orbitalis, suggesting that resolution of the conflict at the phonological level has abolished the semantic ambiguity for heterophones. Reduced activation for all ambiguous words in temporo-parietal regions suggests that although ambiguity enhances controlled lexical selection processes in frontal regions it reduces reliance on bottom-up mapping processes. After presentation of the context, a larger difference between the dominant and subordinate meaning was found for heterophones in all reading-related regions, suggesting a greater engagement for heterophones with the dominant meaning. Conclusions: Altogether these results are consistent with the prominent role of phonological processing in visual word recognition. Finally, despite differences in hemispheric asymmetry between homophones and heterophones, ambiguity resolution, even toward the subordinate meaning, is largely left lateralized.

Memory & Cognition, 2015

Laterality: Asymmetries of Body, Brain and Cognition, 2015

To test the separate and combined abilities of the two cerebral hemispheres to perform controlled... more To test the separate and combined abilities of the two cerebral hemispheres to perform controlled semantic selection and integration processes, Hebrew readers saw pairs of words and had to decide whether the two words were semantically related. The first word in each pair was presented centrally. The second word was presented in the left, right, or central visual field (LVF, RVF, and CVF). We compared response latencies for related pairs in two conditions: In the ambiguous condition, the first word was a homograph (either homophonic or heterophonic) and the second word was related to either its dominant or subordinate meaning. In the unambiguous condition, homographs were replaced with unambiguous control words. Irrespective of VF or homograph type, response times for ambiguous pairs were significantly longer than for unambiguous pairs only when targets were related to the subordinate meaning of the homograph. In the left hemisphere (RVF/LH), this ambiguity effect was larger for heterophones than for homophones, whereas in the right hemisphere (LVF/RH), similar patterns were observed for both types of homographs. Finally, performance patterns in the CVF revealed the same patterns as those in the RVF/LH, and were different from those in the LVF/RH. The implications of these results are discussed.

Writing Systems Research, 2011

Previous research has suggested that reading Arabic is slower than reading Hebrew or English, eve... more Previous research has suggested that reading Arabic is slower than reading Hebrew or English, even among native Arabic readers. We tested the hypothesis that at least part of the difficulty in reading Arabic is due to the visual complexity of Arabic orthography. Third-and sixth-grade native readers of Arabic who were studying Hebrew in school were asked to detect a vowel diacritic in the context of Hebrew words and nonwords, Arabic words and nonwords (including connected and unconnected Arabic letters), and nonletter stimuli that resembled Arabic or Hebrew letters. Participants were better at detecting target vowels in Hebrew than in any of the Arabic conditions. Moreover, target detection in Arabic was better for letter strings containing connected letters than for those containing unconnected letters. The findings extend previous results on Hebrew versus Arabic reading and support a perceptual load account of the source of processing difficulty in reading Arabic. Performance in the Arabic conditions did not reveal a word superiority effect, suggesting that even by sixth grade, reading is not automatized to the point where it can compensate for the the visual complexity of the orthography.

The goal of the present study was to extend the models explaining the missing-letter effect (MLE)... more The goal of the present study was to extend the models explaining the missing-letter effect (MLE) to an additional language and orthography, and to test the role of phonology in silent reading in Arabic. We also examined orthographic effects such as letter position and letter shape, morphological effects such as pseudo-prefixes, and phonological effects such as pronounceability. The results showed that readers miss letters more often in function words and prefixes than in content words, more in second position than in first position, more often when the letters are silent than pronounced, and less often when the letter shape is more symmetric and stable. The results show that these aspects of the missing letter effect can be generalized over writing systems that are not alphabetic, suggesting that the models proposed to explain the MLE in all the orthographies tested may reflect a universal aspect of reading.

Lecture Notes in Computer Science, 2007

Neuropsychology, 2007

This study examined the relationship between morphological structure of languages and performance... more This study examined the relationship between morphological structure of languages and performance asymmetries of native speakers in lateralized tasks. In 2 experiments, native speakers of English (concatenative morphology stem plus affix) and of Hebrew and Arabic (nonconcatenative root plus word-form morphology) were presented with lateralized lexical decision tasks, in which the morphological structure of both words and nonwords was manipulated. In the 1st study, stimuli were presented unilaterally. In the 2nd study, 2 stimuli were presented bilaterally, and participants were cued to respond to 1 of them. Three different indexes of hemispheric integration were tested: processing dissociation, effects of distractor status, and the bilateral effect. Lateralization patterns in the 3 languages revealed both common and language-specific patterns. For English speakers, only the left hemisphere (LH) was sensitive to morphological structure, consistent with the hypothesis that the LH processes right visual field stimuli independently but that the right hemisphere uses LH abilities to process words in the left visual field. In Hebrew and Arabic, both hemispheres are sensitive to morphological structure, and interhemispheric transfer of information may be more symmetrical than in English. The relationship between universal and experience-specific effects on brain organization is discussed.

Journal of Psycholinguistic Research, 2009

The goal of the present study was to examine functioning of late bilinguals in their second langu... more The goal of the present study was to examine functioning of late bilinguals in their second language. Specifically, we asked how native and non-native Hebrew speaking listeners perceive accented and native-accented Hebrew speech. To achieve this goal we used the gating paradigm to explore the ability of healthy late fluent bilinguals (Russian and Arabic native speakers) to recognize words in L2 (Hebrew) when they were spoken in an accent like their own, a native accent (Hebrew speakers), or another foreign accent (American accent). The data revealed that for Hebrew speakers, there was no effect of accent, whereas for the two bilingual groups (Russian and Arabic native speakers), stimuli with an accent like their own and the native Hebrew accent, required significantly less phonological information than the other foreign accents. The results support the hypothesis that phonological assimilation works in a similar manner in these two different groups.

Journal of Neurolinguistics, 2010

Brain and Cognition, 2012

Research investigating hemispheric asymmetries in meaning selection using homophonic homographs (... more Research investigating hemispheric asymmetries in meaning selection using homophonic homographs (e.g., bank), suggests that the left hemisphere (LH) quickly selects contextually relevant meanings, whereas the right hemisphere (RH) maintains a broader spectrum of meanings including those that are contextually irrelevant (e.g., Faust & Chiarello, 1998). The present study investigated cerebral asymmetries in maintaining the multiple meanings of two types of Hebrew homographs: homophonic homographs and heterophonic homographs (e.g., tear). Participants read homographs preceded by a biasing, or a non-biasing sentential context, and performed a lexical decision task on targets presented laterally, 1000 ms after the onset of the sentence-final ambiguous prime. Targets were related to either the dominant or the subordinate meaning of the preceding homograph, or unrelated to it. When targets were presented in the LVF/RH, dominant and subordinate meanings, of both types of homographs, were retained only when they were supported by context. In a non-biasing context, only dominant meanings of homophonic homographs were retained. Alternatively, when targets were presented in the RVF/LH, priming effects for homophonic homographs were only evident when meanings were supported by both context and frequency (i.e., when context favored the dominant meaning). In contrast, heterophonic homographs resulted in activation of dominant meanings, in all contexts, and activation of subordinate meanings, only in subordinate-biasing contexts. The results challenge the view that a broader spectrum of meanings is maintained in the right than in the left hemisphere and suggest that hemispheric differences in the time course of meaning selection (or decay) may be modulated by phonology.

Brain and Cognition, 2009

The present study investigated cerebral asymmetries in accessing multiple meanings of two types o... more The present study investigated cerebral asymmetries in accessing multiple meanings of two types of homographs: homophonic homographs (e.g., bank) and heterophonic homographs (e.g., tear). Participants read homographs preceded by either a biasing or a non-biasing sentential context and performed a lexical decision on lateralized targets presented 150 ms after onset of the sentence-final ambiguous prime. Targets were either related to the dominant or the subordinate meaning of the preceding homograph or were unrelated to it. In the case of homophonic homographs-our results converge with previous findings: both activation and selection processes are faster in the LH than in the RH. Importantly, however, in the case of heterophonic homographs-opposite asymmetries were found. These results suggest that semantic asymmetries are modulated by phonology. They are discussed in the context of a model of functional architecture of reading in the two hemispheres in which orthography, phonology and semantics are fully interconnected in the LH, whereas in the RH, orthography and phonology are not directly connected, such that phonological processes are mediated by semantics.

Behavioral and Brain Functions, 2012

Annals of Mathematics and Artificial Intelligence, 2010

A computational model for reading that takes into account the different processing abilities of t... more A computational model for reading that takes into account the different processing abilities of the two cerebral hemispheres is presented. This dual hemispheric reading model closely follows the original computational lines due to Kowamoto (J Mem Lang 32:474-516, 1993) but postulates a difference in architecture between the right and left hemispheres. Specifically it is assumed that orthographic, phonological and semantic units are completely connected in the left hemisphere, while there are no direct connections between phonological and orthographic units in the right hemisphere. It is claimed that this architectural difference results in hemisphere asymmetries in resolving lexical ambiguity and more broadly in the processing of written words. Simulation results bear this out. First, we show that the two networks successfully simulate the time course of lexical selection in the two cerebral hemispheres. Further, we were able to see a computational advantage of two separate networks, when information is transferred from the right hemisphere network to the left hemisphere network. Finally, beyond

Writing Systems Research, 2013