Inter- and intra- hemispheric interactions in reading ambiguous words

The present study investigated how the brain processes words with multiple meanings. Specifically, we examined the inter- and intra-hemispheric connectivity of unambiguous words compared to two types of ambiguous words: homophonic homographs, which have multiple meanings mapped to a single phonological representation and orthography, and heterophonic homographs, which have multiple meanings mapped to different phonological representations but the same orthography. Using a semantic relatedness judgment task and effective connectivity analysis via Dynamic Causal Modeling (DCM) on previously published fMRI data (Bitan et al., 2017), we found that the two hemispheres compete in orthographic processing during the reading of unambiguous words. For heterophonic homographs, we observed increased connectivity within the left hemisphere, highlighting the importance of top-down re-activation of orthographic representations by phonological ones for considering alternative meanings. For homophonic homographs, we found a flow of information from the left to the right hemisphere and from the right to the left, indicating that the brain retrieves different meanings using different pathways. These findings provide novel insights into the complex mechanisms involved in language processing and shed light on the different communication patterns within and between hemispheres during the processing of ambiguous and unambiguous words.

Interactions of lexical and conceptual representations: Evidence from EEG

We examined whether meanings automatically activate linguistic forms, and whether these forms affect semantic decisions. Participants were presented sequentially with pairs of pictures and decided whether the objects in the pictures were related. At no point did they name the pictures. The object names of the experimental stimuli were ambiguous either in orthography (homographs), phonology (homophones), or both (homonyms), or unambiguous. We show that the lexical characteristics of the name of the objects affect a semantic decision about real world relations, in an online measure (N400), in addition to offline behavioral measures. We show a dissociation between conceptual and lexical recognition, where an earlier component (N230), was affected by relatedness, but was not sensitive to the lexical characteristics. We interpret this as supporting the hypothesis that semantic recognition occurs before the automatic lexical activation of the object name, but that once linguistic representations are activated, they affect semantic integration.

Interhemispheric transfer of visual information: Meaningfulness and response formation

We examined whether Redundancy Gain (RG) can be dissociated from the response stage of a go/nogo paradigm, and whether the meaningfulness of a stimulus modulates the stage at which interhemispheric transfer occurs. Experiment 1 used a lateralized match-to-category paradigm, taken from categories with varying meaningfulness. Experiment 2 presented a novel design, which separates the perceptual stage from response formation, in examination of RG. A sequence of two stimuli was presented. Participants responded by matching the category of the second stimulus to that of the first. The redundant stimulus could appear at the first or the second stage, thus redundancy gain could be separated from the response. Experiment 1 revealed that redundancy gain occurs earlier in the process of stimulus identification for highly meaningful stimuli than for less meaningful stimuli. The results of Experiment 2 support the hypothesis that redundancy gain results from interhemispheric integration of perceptual information, rather than response-formation. Results from both experiments suggest that redundancy gain arises from interhemispheric integration in the perceptual stage, and the efficiency of this integration depends on the meaningfulness of the stimulus. These results are relevant to current hypotheses about the physiological mechanisms underlying RG.

Competition in context: response selection within the supervisory attentional system model

We examined the effects of context bias and target exposure duration on error rates (ERR) and response times (RTs) in letter choice task within context. Surface Electromyography (sEMG) was recorded in both hands during context presentation, as a measure of readiness to respond. The goal was to affect the outcome of the task by manipulating relative schemata activation levels prior to target onset, as per the Supervisory Attentional System model. At short exposures, context bias and sEMG activity affected ERR, whereas at longer durations, RTs were affected. Context bias mediated the effect of sEMG activity. Increasing activity in both hands led to higher ERR and RTs in incongruent context. Non-increasing activity in the non-responding lead to lack of relationship between sEMG activity and behavior, irrespective of context. sEMG activity in both hands was found to be interrelated and context-sensitive. These results conform to the predictions of the Supervisory Attentional Model.

Phonology and orthography in deaf readers: Evidence from a lateralized ambiguity resolution paradigm

This study explored differences between the two hemispheres in processing written words among deaf readers. The main hypothesis was that impoverished phonological abilities of deaf readers may lead to atypical patterns of hemispheric involvement. To test this, deaf participants completed a metalinguistic awareness test to evaluate their orthographic and phonological awareness. Additionally, they were asked to read biased or neutral target sentences ending with an ambiguous homograph, with each sentence followed by the request to make a rapid lexical decision on a target word presented either to the left (LH) or right hemisphere (RH). Targets were either related to the more frequent, dominant, meaning of the homograph, to the less frequent, subordinate, meaning of the homograph or were not related at all. An Inverse Efficiency Score based on both response latency and accuracy was calculated and revealed that deaf readers' RH perform better than their LH. In contrast to hearing readers who in previous studies manifested left hemisphere dominance when completed the same research design. The apparent divergence of deaf readers' hemisphere lateralization from that of hearing counterparts seems to validate previous findings suggesting greater reliance on RH involvement among deaf individuals during visual word recognition.

Semantic and affective manifestations of ambi (valence)

People sometimes report both pleasant and unpleasant feelings when presented with affective stimuli. However, what is reported as "mixed emotions" might reflect semantic knowledge about the stimulus (Russell, J. A. (2017). Mixed emotions viewed from the psychological constructionist perspective. Emotion Review, 9(2), 111-117). The following research examines to what degree self-reported mixed emotions represent actual feelings compared to knowledge about the stimulus. In a series of three experiments, participants reported either their feelings or their knowledge in response to affective stimuli. In Experiment 1, we sampled the entire IAPS pictorial space and examined the proportion of mixed emotion ratings using feelings-focused and knowledge-focused self-reports. We found a higher degree of mixed emotions under knowledge-focused than feelings-focused self-reports. In Experiment 2, we used a priori selected pictures to elicit mixed emotions. The proportion of mixed emotions was again higher under knowledge-focused instructions. In Experiment 3, we used movie clips that were previously used to elicit mixed emotions. In contrast to Experiments 1 and 2, there was no difference between feelings-focused and knowledge-focused self-reports. The results suggest a strong semantic component and a weak experiential component of self-reports in the case of pictorial stimuli. However, ambivalent movie clips elicited a stronger experiential component, thus supporting the existence of mixed emotions at the level of feelings.

Separability of Lexical and Morphological Knowledge: Evidence from Language Minority Children

Lexical and morphological knowledge of school-aged children are correlated with each other, and are often difficult to distinguish. One reason for this might be that many tasks currently used to assess morphological knowledge require children to inflect or derive real words in the language, thus recruiting their vocabulary knowledge. The current study investigated the possible separability of lexical and morphological knowledge using two complementary approaches. First, we examined the correlations between vocabulary and four morphological tasks tapping different aspects of morphological processing and awareness, and using either real-word or pseudo-word stimuli. Thus, we tested the hypothesis that different morphological tasks recruit lexical knowledge to various degrees. Second, we compared the Hebrew vocabulary and morphological knowledge of 5th grade language minority speaking children to that of their native speaking peers. This comparison allows us to ask whether reduced exposure to the societal language might differentially influence vocabulary and morphological knowledge. The results demonstrate that indeed different morphological tasks rely on lexical knowledge to varying degrees. In addition, language minority students had significantly lower performance in vocabulary and in morphological tasks that recruited vocabulary knowledge to a greater extent. In contrast, both groups performed similarly in abstract morphological tasks with a lower vocabulary load. These results demonstrate that lexical and morphological knowledge may rely on partially separable learning mechanisms, and highlight the importance of distinguishing between these two linguistic components.

Phonological ambiguity modulates resolution of semantic ambiguity during reading: An fMRI study of Hebrew

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. (PsycINFO Database Record

The Role of Emergent Bilingualism in the Development of Morphological Awareness in Arabic and Hebrew

PURPOSE

The purpose of the present study was to investigate the role of dual language development and cross-linguistic influence on morphological awareness in young bilinguals' first language (L1) and second language (L2). We examined whether (a) the bilingual children (L1/L2 Arabic and L1/L2 Hebrew) precede their monolingual Hebrew- or Arabic-speaking peers in L1 and L2 morphological awareness, and (b) 1 Semitic language (Arabic) has cross-linguistic influence on another Semitic language (Hebrew) in morphological awareness.

METHOD

The study sample comprised 93 six-year-old children. The bilinguals had attended bilingual Hebrew-Arabic kindergartens for 1 academic year and were divided into 2 groups: home language Hebrew (L1) and home language Arabic (L1). These groups were compared to age-matched monolingual Hebrew speakers and monolingual Arabic speakers. We used nonwords similar in structure to familiar words in both target languages, representing 6 inflectional morphological categories.

RESULTS

L1 Arabic and L1 Hebrew bilinguals performed significantly better than Arabic- and Hebrew-speaking monolinguals in the respective languages. Differences were not found between the bilingual groups. We found evidence of cross-linguistic transfer of morphological awareness from Arabic to Hebrew in 2 categories-bound possessives and dual number-probably because these categories are more salient in Palestinian Spoken Arabic than in Hebrew.

CONCLUSIONS

We conclude that children with even an initial exposure to L2 reveal acceleration of sensitivity to word structure in both of their languages. We suggest that this is due to the fact that two Semitic languages, Arabic and Hebrew, share a common core of linguistic features, together with favorable contextual factors and instructional factors.

Controlled semantic processes within and between the two cerebral hemispheres

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.

The missing link in the embodiment of syntax: prosody

Neurolinguistic theories are challenged by the amodal abstract representations assumed by linguists. Embodied linguistics offers a conceptualization of the relationship between linguistic representation, experience, and the brain. Findings correlating brain activation patterns with referential features of words (e.g., body parts), suggest that the mechanism underlying linguistic embodiment is an "action-perception simulation". This mechanism accounts for embodied representation of words, but is harder to adapt to syntactic abstractions. We suggest that prosody is the missing link. Prosody is a sensory-motor phenomenon that can evoke an "action-perception simulation" that underpins the syntax-experience-brain association. Our review discusses different embodiment models and then integrates psycholinguistic and neurocognitive studies into a new approach to linguistic embodiment. We propose a novel implementation of the syntax-experience-brain relationship via the mapping between the temporo-spectral aspects of speech prosody and temporo-spectral patterns of synchronized behavior of neural populations. We discuss the potential implications for psycho- and neuro-linguistic research.

Fact retrieval and memory consolidation for a movement sequence: bidirectional effects of 'unrelated' cognitive tasks on procedural memory

The generation of long-term memory for motor skills can be modulated by subsequent motor experiences that interfere with the consolidation process. Recent studies suggest that even a non-motor task may adversely affect some aspects of motor sequence memory. Here we show that motor sequence memory can be either enhanced or reduced, by different cognitive tasks. Participants were trained in performing finger movement sequences. Fully explicit instructions about the target sequence were given before practice. The buildup of procedural knowledge was tested at three time-points: immediately before training (T1), after practice (T2), and 24 hours later (T3). Each participant performed the task on two separate occasions; training on a different movement sequence on each occasion. In one condition, interference, participants performed a non-motor task immediately after T2. Half the participants solved simple math problems and half performed a simple semantic judgment task. In the baseline condition there was no additional task. All participants improved significantly between T1 and T2 (within-session gains). In addition, in the baseline condition, performance significantly improved between T2 and T3 (delayed 'off-line' gains). Solving math problems significantly enhanced these delayed gains in motor performance, whereas performing semantic decisions significantly reduced delayed gains compared to baseline. Thus, procedural motor memory consolidation can be either enhanced or inhibited by subsequent cognitive experiences. These effects do not require explicit or implicit new learning. The retrieval of unrelated, non-motor, well established knowledge can modulate procedural memory.

Phonological and orthographic visual word recognition in the two cerebral hemispheres: Evidence from Hebrew

Studies on the cerebral mechanisms of reading have mostly used Latin-based writing systems and assume that the left, but not the right, cerebral hemisphere is capable of phonological processing. The present study used Hebrew as the test language to examine the effects of phonological and orthographic information in the two hemispheres. In unvoweled Hebrew script, words are read via consonant information alone. We used two naming tasks with an interference paradigm, where phonemically, orthographically, and figurally incorrect vowel information conflicted with the consonant information of words presented in the left, right, or central visual fields. Interference patterns indicated that the left hemisphere automatically transforms graphemes into phonemes (Experiments 1 and 2), whereas the right hemisphere processes vowel diacritics as visual objects (Experiment 1), although it possesses some phonological categories (Experiment 2). The significance of these findings for models of visual word recognition in the cerebral hemispheres is discussed.

The contribution of the two hemispheres to lexical decision in different languages

BACKGROUND

Both reading words and text in Arabic is slower than in other languages, even among skilled native Arabic speakers Previously we have shown that the right hemisphere (RH) had difficulty in matching Arabic letters, and suggested that it cannot contribute to word recognition in Arabic. In this study we tested this finding directly.

METHOD

We used the Divided Visual Field (DVF) lexical decision (LD) paradigm to assess hemispheric function during reading. The experiment had two conditions (unilateral and bilateral). In the unilateral condition, the target stimulus was presented unilaterally to the left or the right visual field. In the bilateral condition two stimuli were presented simultaneously, and participants were cued as to which one was the target. Three groups of participants were tested: Arabic speakers, Hebrew speakers, and English speakers. Each group was tested in their native language.

RESULTS

For Hebrew and English speakers, performance in both visual fields was significantly better in the unilateral than in the bilateral condition. For Arabic speakers, performance in the right visual field (RVF, where stimuli are presented directly to the left hemisphere) did not change in the two conditions. Performance in the LVF (when stimuli are presented directly to the right hemisphere) was at chance level in the bilateral condition, but not in the unilateral condition.

CONCLUSION

We interpret these data as supporting the hypothesis that in English and Hebrew, both hemispheres are involved in LD, whereas in Arabic, the right hemisphere is not involved in word recognition.

Neuropsychological psychopathology measures in women with eating disorders, their healthy sisters, and nonrelated healthy controls

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.

Perception of emotion and bilateral advantage in women with eating disorders, their healthy sisters, and nonrelated healthy controls

BACKGROUND

Eating disorders (EDs) are characterized not only by disordered eating, but also by other psychopathology. In this exploratory study, we examined the ability of women with different diagnoses of EDs, their unaffected sisters, and healthy unrelated controls to recognize their own and other's emotions. We also looked at interhemispheric integration of emotion recognition and its relationship with depression.

METHOD

Five groups of women participated: 1. anorexia nervosa restricting (AN-R) and 2. (AN-B/B) binge/purge, 3. bulimia nervosa binge/purge, (BN-B/P), 4. healthy sisters of women with ED, and 5. unrelated healthy controls. We used two questionnaires measuring alexithymia and depression, and two lateralized experimental tasks requiring recognition of facial emotion. Unilateral versus bilateral presentation allow the indexing of interhemispheric integration.

RESULTS

Alexithymia: All the ED groups were found to be more alexithymic and depressed on the self report scales compared to the two healthy groups. Depression completely mediated alexithymia in the AN-R group but not in the AN-B/P and BN-B/P patients. Sisters of ED women were more alexithymic than unrelated controls. Lateralized facial emotion recognition: ED women showed no deficits in recognizing basic emotions. However, the clinical groups did not show a bilateral advantage whereas the two healthy groups did so.

CONCLUSIONS

We present three conclusions: we show, for the first time, evidence for a deficit in hemispheric integration in EDs. This implies that EDs may be a disconnection syndrome; alexithymia characterizes women with EDs and members of their family; depression is manifested differently in AN-R, than in women who binge/purge.

Social cognition in eating disorders: encoding and representational processes in binging and purging patients

OBJECTIVE

The present study investigates social cognition impairments in 29 women with bingeing/purging spectrum eating disorders (ED) compared to 27 healthy controls.

METHOD

Measures were used to examine encoding and representational processes in relation to affect perception and affect attribution, as well as the ability to recognize mental causality in social relationships.

RESULTS

ED patients failed to correctly encode causality in interpersonal relations, exhibited deficits in their ability to ascribe behaviour to mental states, and showed a greater tendency to attribute negative affects in interpersonal relationships. Stepwise regression analyses suggested that ED symptoms could account for deficits in the recognition of causality in interpersonal relations.

CONCLUSIONS

In addition to addressing ED symptoms, social cognition deficits should be addressed in the psychological treatment of EDs.

The relationship between theory of mind and autobiographical memory in high-functioning autism and Asperger syndrome

The relationship between theory of mind (ToM) and autobiographical memory (AM) in high-functioning autism (HFA) and Asperger syndrome (AS) has never been investigated. Here, we show that ToM abilities could be predicted by levels of AM in HFA and AS as compared to controls, suggesting that difficulties in AM are closely related to ToM impairments in HFA and AS.

Listening with an accent: speech perception in a second language by late bilinguals

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.

Different laterality patterns of the error-related negativity in corrected and uncorrected errors

While measuring event-related brain potentials, a divided visual field paradigm was used to discern laterality patterns of the error-related negativity (ERN) in healthy human participants. Two tasks of hemispheric specialty were used (bargraph judgement, lexical decision) and a flanker task. For corrected errors in all tasks, stronger ERN amplitude was found following right visual field presentation. For corrected errors in the specialised tasks, shorter ERN latency was revealed on the side to which the stimulus was presented, while for uncorrected errors it was shorter on the other side. In the flanker task, ERN latency after corrected errors was shorter over the RH regardless of the side to which the stimulus was presented. Results are interpreted to reveal patterns of hemispheric specialisation, independence, and cooperation in error detection that depend on the type of error been committed.

Hemispheric sensitivities to lexical and contextual information: evidence from lexical ambiguity resolution

The present study examined the manner in which both hemispheres utilize prior semantic context and relative meaning frequency during the processing of homographs. Participants read sentences biased toward the dominant or the subordinate meaning of their final homograph, or unbiased neutral sentences, and performed a lexical decision task on lateralized targets presented 250ms after the onset of the sentence-final ambiguous prime. Targets were either related to the dominant or the subordinate meaning of the preceding homograph, or unrelated to it. Performance asymmetry was found in the absence of a biasing context: dominant-related targets were exclusively facilitated in the RVF/LH, whereas both dominant- and subordinate-related targets were facilitated in the LVF/RH. Performance symmetry was found in the presence of a biasing context: dominant-related targets were exclusively activated in dominant-biasing contexts, whereas both dominant- and subordinate-related targets were facilitated in subordinate-biasing contexts. The implications of the results for both general and hemispheric models of word processing are discussed.

Metalinguistic awareness and reading performance: a cross language comparison

The study examined two questions: (1) do the greater phonological awareness skills of billinguals affect reading performance; (2) to what extent do the orthographic characteristics of a language influence reading performance and how does this interact with the effects of phonological awareness. We estimated phonological metalinguistic abilities and reading measures in three groups of first graders: monolingual Hebrew speakers, bilingual Russian-Hebrew speakers, and Arabic-speaking children. We found that language experience affects phonological awareness, as both Russian-Hebrew bilinguals and the Arabic speakers achieved higher scores on metalinguistic tests than Hebrew speakers. Orthography affected reading measures and their correlation with phonological abilitites. Children reading Hebrew showed better text reading ability and significant correlations between phonological awareness and reading scores. Children reading Arabic showed a slight advantage in single word and nonword reading over the two Hebrew reading groups, and very weak relationships between phonological abilities and reading performance. We conclude that native Arabic speakers have more difficulty in processing Arabic orthography than Hebrew monolinguals and bilinguals have in processing Hebrew orthography, and suggest that this is due to the additional visual complexity of Arabic orthography.

Do the hemispheres watch each other? Evidence for a between-hemispheres performance monitoring

This study tested the hypothesis that when tasks are complex, response selection and performance monitoring are divided across the hemispheres, and when tasks are simple, response selection and error monitoring are done in the same hemisphere. Using a divided visual field paradigm, the authors presented a target and an interference stimulus, either to the same visual field or to different visual fields, and encouraged error correction. The interference stimulus was timed to interfere with posited error processing. Four tasks were used: bar graph identification, lexical decision, and complex and simple versions of the flankers task. The first three tasks revealed a pattern of contralateral interference, suggesting that error processing occurred in the hemisphere that did not process the initial target. The fourth task showed ipsilateral interference, suggesting that the same hemisphere processed the target and monitored itself. The authors conclude that the pattern of hemispheric cooperation in error processing is affected by task complexity.

Morphological structure and hemispheric functioning: The contribution of the right hemisphere to reading in different languages

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.

Brain correlates of discourse processing: an fMRI investigation of irony and conventional metaphor comprehension

Higher levels of discourse processing evoke patterns of cognition and brain activation that extend beyond the literal comprehension of sentences. We used fMRI to examine brain activation patterns while 16 healthy participants read brief three-sentence stories that concluded with either a literal, metaphoric, or ironic sentence. The fMRI images acquired during the reading of the critical sentence revealed a selective response of the brain to the two types of nonliteral utterances. Metaphoric utterances resulted in significantly higher levels of activation in the left inferior frontal gyrus and in bilateral inferior temporal cortex than the literal and ironic utterances. Ironic statements resulted in significantly higher activation levels than literal statements in the right superior and middle temporal gyri, with metaphoric statements resulting in intermediate levels in these regions. The findings show differential hemispheric sensitivity to these aspects of figurative language, and are relevant to models of the functional cortical architecture of language processing in connected discourse.

Does each hemisphere monitor the ongoing process in the contralateral one?

The present study was conducted to examine hemispheric division of labor in the initial processing and error monitoring in tasks for which hemispheric specialization exists. We used lexical decision as a left hemisphere task and bargraph judgment as a right hemisphere task, and manipulated cognitive load. Participants had to respond to one of two stimuli presented to both visual fields and were instructed to correct their errors. To achieve enough correctable errors, participants were encouraged to respond quickly by using a bonus system. The results showed the classical asymmetry for initial responses in both tasks and reversed asymmetry for corrections in the bargraph task at both load conditions, and in the lexical decision task at the high load condition. The results suggest that each hemisphere monitors the ongoing process in the contralateral one and that the dissociation of initial process and its monitoring grows with load of task.

Orthography and the Hemispheres: Visual and Linguistic Aspects of Letter Processing

Hebrew and Arabic are Semitic languages with a similar morphological structure and orthographies that differ in visual complexity. Two experiments explored the interaction of the characteristics of orthography and hemispheric abilities on lateralized versions of a letter-matching task (Experiment 1) and a global-local task (Experiment 2). In Experiment 1, native Hebrew readers and native Arabic readers fluent in Hebrew matched letters in the 2 orthographies. The results support the hypothesis that Arabic orthography is more difficult than Hebrew orthography for participants who can read both languages and that this difficulty has its strongest effects in the left visual field. In Experiment 2, native Arabic speakers performed a global-local letter detection task with Arabic letters with 2 types of inconsistent stimuli: different and similar. The results support the hypothesis that the right hemisphere of skilled Arabic readers cannot distinguish between similar Arabic letters, whereas the left hemisphere can.

The characteristics of arabic orthography slow its processing

The present study was designed to evaluate whether the complexity of Arabic orthography increases its perceptual load, thus slowing word identification. Adolescent Arabic speakers who mastered Hebrew as a second language completed oral and visual versions of the Trail Making Test (TMT; J. E. Parington & R. G. Lieter, 1949) in both languages. Oral TMT required declaiming consecutive numbers or alternation between numbers and letters. Visual TMT required connecting Arabic or Indian numbers and alternation between letters and numbers. Performance in Hebrew and Arabic oral TMT did not differ. Performance was significantly slower in Arabic visual TMT. These results indicate that Arabic speakers process Arabic orthography (1st language) slower than Hebrew orthography (2nd language) and suggest that this is due to the complexity of Arabic orthography.

Narrative analysis in developmental social and linguistic pathologies: dissociation between emotional and informational language use

This study examined the use of emotional and informational aspects of language in populations that demonstrate developmental social-emotional and linguistic pathologies. We tested high-functioning autistic (HFA) individuals because this group reveals deficiencies in social-emotional and informative aspects of language as well as abnormalities in sociability. We tested Williams syndrome (WS) individuals because of the claim that the social-emotional aspects of language use and sociability are differentially preserved in the context of mental retardation. We compared the performance of these two groups with two groups of control children (7- and 11-year-olds). All of the participants viewed a slide show depicting an event and were asked to retell the story. These narratives were coded for emotional and informational elements. The results showed that on measures of emotional elements, the WS group patterned with the control groups and only the HFA participants received lower scores, while on the informational elements, the two pathological groups did not differ, and both were lower than the controls. The results suggest that the preservation of language among WS individuals is specific for the emotional aspects of language.

Linguistic and nonlinguistic auditory processing of rapid vowel formant (F2) modulations in university students with and without developmental dyslexia

To help resolve the issue of whether developmental dyslexia (DD) is related to central auditory processing deficits or to language-specific processing deficits, we had nine dyslectic and nine nondyslectic right-handed undergraduate students perform linguistic (Experiment 1: phoneme identification) and nonlinguistic (Experiment 2: formant rate change detection) tasks. In Experiment 1, subjects listened to synthetic vowels whose second formant (F2) was modulated sinusoidally with F1, F3, and F4 held constant. F2 modulation rate (4-18 Hz) was manipulated within and across stimuli. The groups did not differ in phoneme identification. Experiment 2 was run three times and showed that the control subjects' performance improved across runs whereas the dyslexics' deteriorated across runs (p < .0001), suggesting practice and fatigue effects, respectively. Performance on the two experiments correlated significantly and negatively for the dyslexic subjects only. These results suggest that resource depletion or frontal lobe dysfunction may be implicated in developmental dyslexia.

The timing deficit hypothesis of dyslexia and its implications for Hebrew reading

Vast amounts of neuropsychological evidence have been collected in recent years in support of the hypothesis that developmental dyslexia is caused not only by phonological deficits, but also by timing deficits that affect all senses (e.g., Tallal, Miller, & Fitch, 1995; Stein & Walsh, 1997). In parallel, recent developments in the study of Hebrew reading place heavy emphasis on root awareness in the mental lexicon and early root extraction in the process of word identification (e.g., Frost, Forster, & Deutch, 1997). The present study creates a link between the timing hypothesis and the special demands of Hebrew reading. The performance of dyslexics and normally reading children is compared on tasks requiring visual extraction of trigrams that approximates extracting roots out of Hebrew words. Partial findings show that dyslexics take longer and make more errors while performing trigram extractions on all levels examined, and that sequentiality in the task affects dyslexics and skilled readers in different ways.

Cross-language tests of hemispheric strategies in reading nonwords

Four experiments explored the effects of specific language characteristics on hemispheric functioning in reading nonwords using a lateralized trigram identification task. Previous research using nonsense consonant-vowel-consonant (CVC) trigrams has shown that total error scores reveal a right visual field (RVF) advantage in Hebrew, Japanese, and English. Qualitative error patterns have shown that the right hemisphere uses a sequential strategy, whereas the left hemisphere uses a more parallel strategy in English but shows the opposite pattern in Hebrew. Experiment 1 tested whether this is due to the test language or to the native language of the participants. Results showed that native language had a stronger effect on hemispheric strategies than test language. Experiment 2 showed that latency to target letters in the CVCs revealed the same asymmetry as qualitative errors for Hebrew speakers but not for English speakers and that exposure duration of the stimuli affected misses differentially according to letter position. Experiment 3 used number trigrams to equate reading conventions in the 2 languages. Qualitative error scores still revealed opposing asymmetry patterns. Experiments 1-3 used vertical presentations. Experiment 4 used horizontal presentation, which eliminated sequential processing in both hemispheres in Hebrew speakers, whereas English speakers still showed sequential processing in both hemispheres. Comparison of the 2 presentations suggests that stimulus arrangement affected qualitative errors in the left visual field but not the RVF for English speakers and in both visual fields for Hebrew speakers. It is suggested that these differences result from orthographic and morphological differences between the languages: Reading Hebrew requires attention to be deployed to all the constituents of the stimulus in parallel, whereas reading English allows sequential processing of the letters in both hemispheres. Implications of cross-language studies for models of hemispheric function are discussed.

Cross-language tests of hemispheric strategies in reading nonwords

Four experiments explored the effects of specific language characteristics on hemispheric functioning in reading nonwords using a lateralized trigram identification task. Previous research using nonsense consonant-vowel-consonant (CVC) trigrams has shown that total error scores reveal a right visual field (RVF) advantage in Hebrew, Japanese, and English. Qualitative error patterns have shown that the right hemisphere uses a sequential strategy, whereas the left hemisphere uses a more parallel strategy in English but shows the opposite pattern in Hebrew. Experiment 1 tested whether this is due to the test language or to the native language of the participants. Results showed that native language had a stronger effect on hemispheric strategies than test language. Experiment 2 showed that latency to target letters in the CVCs revealed the same asymmetry as qualitative errors for Hebrew speakers but not for English speakers and that exposure duration of the stimuli affected misses differentially according to letter position. Experiment 3 used number trigrams to equate reading conventions in the 2 languages. Qualitative error scores still revealed opposing asymmetry patterns. Experiments 1-3 used vertical presentations. Experiment 4 used horizontal presentation, which eliminated sequential processing in both hemispheres in Hebrew speakers, whereas English speakers still showed sequential processing in both hemispheres. Comparison of the 2 presentations suggests that stimulus arrangement affected qualitative errors in the left visual field but not the RVF for English speakers and in both visual fields for Hebrew speakers. It is suggested that these differences result from orthographic and morphological differences between the languages: Reading Hebrew requires attention to be deployed to all the constituents of the stimulus in parallel, whereas reading English allows sequential processing of the letters in both hemispheres. Implications of cross-language studies for models of hemispheric function are discussed.

Individual differences in lateralization: effects of gender and handedness

Male and female left- and right-handers participated in 3 experiments designed to investigate 3 components of performance asymmetry in lateralized tasks. Experiment 1 used a consonant-vowel-consonant (CVC) identification task measuring quantitative differences in hemispheric abilities and hemispheric control and qualitative differences in hemispheric strategies. The quantitative data revealed that left-handers have a smaller performance asymmetry than do right-handers and that both groups have the same degree of increased accuracy when stimuli are presented bilaterally. Handedness affected the qualitative measures of men, not of women. Experiment 2 used nominal and physical letter-matching tasks with bilateral presentations and measured the flexibility of callosal function. The results suggest that left-handers have less flexible interhemispheric communication than do right-handers and show no effect of gender. Experiment 3 used a chair identification task indexing hemispheric arousal bias. Left-handers tended to have more aroused right than left hemispheres, whereas the distribution of right-handers was centered around 0 arousal bias. Intertask analyses revealed a relationship between arousal bias and metacontrol, where individuals with more aroused right hemispheres tended to use a right-hemisphere strategy in the bilateral condition of the CVC experiment. Intercorrelations between measures from the experiments revealed only a limited relationship between metacontrol patterns in the CVC task and a measure of callosal flexibility in the physical letter-matching task. The results are discussed in the context of the relationships between dimensions of hemispheric asymmetry.

Individual differences in lateralization: effects of gender and handedness

Male and female left- and right-handers participated in 3 experiments designed to investigate 3 components of performance asymmetry in lateralized tasks. Experiment 1 used a consonant-vowel-consonant (CVC) identification task measuring quantitative differences in hemispheric abilities and hemispheric control and qualitative differences in hemispheric strategies. The quantitative data revealed that left-handers have a smaller performance asymmetry than do right-handers and that both groups have the same degree of increased accuracy when stimuli are presented bilaterally. Handedness affected the qualitative measures of men, not of women. Experiment 2 used nominal and physical letter-matching tasks with bilateral presentations and measured the flexibility of callosal function. The results suggest that left-handers have less flexible interhemispheric communication than do right-handers and show no effect of gender. Experiment 3 used a chair identification task indexing hemispheric arousal bias. Left-handers tended to have more aroused right than left hemispheres, whereas the distribution of right-handers was centered around 0 arousal bias. Intertask analyses revealed a relationship between arousal bias and metacontrol, where individuals with more aroused right hemispheres tended to use a right-hemisphere strategy in the bilateral condition of the CVC experiment. Intercorrelations between measures from the experiments revealed only a limited relationship between metacontrol patterns in the CVC task and a measure of callosal flexibility in the physical letter-matching task. The results are discussed in the context of the relationships between dimensions of hemispheric asymmetry.

Language experience and right hemisphere tasks: the effects of scanning habits and multilingualism

This study explores the effects of multilingualism and reading scanning habits on right hemisphere (RH) abilities. Native Hebrew speakers and Arabic-Hebrew bilinguals performed three tasks. Experiment 1 employed an odd/even decision paradigm on lateralized displays of bar graphs. Both groups of subjects displayed the expected LVFA within the range previously reported for readers of English. Experiment 2 consisted of a chair identification task designed to tap asymmetry of hemispheric arousal and a chimeric face task designed to tap RH specialization for facial emotion. Neither scanning habits nor language experience affected performance on the chair task. Scanning habits seem to have affected performance on the chimeric faces task: there was no preference for the left smile in these right-to-left readers, as opposed to previous results in the literature using left-to-right readers. Correlations between measures from the three tasks and all the subject's scores on an English proficiency test and on a Hebrew test for the bilinguals reveal tentative relationships between proficiency in a second language and RH abilities. The results do not support the hypothesis that multilingualism can affect the manner in which these nonlanguage tasks are subserved by the RH. They do support the hypothesis that scanning habits particular to specific languages can affect performance asymmetries on some nonlanguage tasks that have been posited to reflect RH specialization.

Reading direction and attention: effects on lateralized ignoring

The effects of the scan for the first element in reading (leftmost in English, rightmost in Hebrew) on the ability of subjects to ignore irrelevant stimuli in one visual field more than in the other were investigated. The hypothesis tested was that English readers would have a harder time ignoring irrelevant stimuli in the left visual field than in the right visual field, with the opposite pattern predicted for readers of Hebrew. The paradigm employed by Banich (Banich & Belger, 1990) was used with two letter matching tasks. The results showed that when an irrelevant letter was present, English readers responded more slowly in the right than in the left visual field, and Hebrew readers showed the opposite pattern (Experiment 1). This interaction did not occur when the irrelevant letter was deleted (Experiment 2). These findings are discussed in terms of their relation to eye movements and covert attention and to the use of bilateral displays in neuropsychological experiments.

Individual variation in hemispheric asymmetry: multitask study of effects related to handedness and sex

Functional hemispheric asymmetries were examined for right- or left-handed men and women. Tasks involved (a) auditory processing of verbal material, (b) processing of emotions shown on faces, (c) processing of visual categorical and coordinate spatial relations, and (d) visual processing of verbal material. Similar performance asymmetries were found for the right-handed and left-handed groups, but the average asymmetries tended to be smaller for the left-handed group. For the most part, measures of performance asymmetry obtained from the different tasks did not correlate with each other, suggesting that individual subjects cannot be simply characterized as strongly or weakly lateralized. However, ear differences obtained in Task 1 did correlate significantly with certain visual field differences obtained in Task 4, suggesting that both tasks are sensitive to hemispheric asymmetry in similar phonetic or language-related processes.

Individual variation in hemispheric asymmetry: multitask study of effects related to handedness and sex

Functional hemispheric asymmetries were examined for right- or left-handed men and women. Tasks involved (a) auditory processing of verbal material, (b) processing of emotions shown on faces, (c) processing of visual categorical and coordinate spatial relations, and (d) visual processing of verbal material. Similar performance asymmetries were found for the right-handed and left-handed groups, but the average asymmetries tended to be smaller for the left-handed group. For the most part, measures of performance asymmetry obtained from the different tasks did not correlate with each other, suggesting that individual subjects cannot be simply characterized as strongly or weakly lateralized. However, ear differences obtained in Task 1 did correlate significantly with certain visual field differences obtained in Task 4, suggesting that both tasks are sensitive to hemispheric asymmetry in similar phonetic or language-related processes.

Nominal and physical decision criteria in same-different judgments

We propose a model in which the physical and nominal dimensions of letter pairs are compared independently of whether subjects use physical (shape task) or nominal (name task) identity as the decision criterion. We attempt to explain the fast-same effect, the preponderance of false-different errors, and the nominal-physical disparity as results of congruent and incongruent outputs of physical and nominal comparison devices that function in both tasks. Subjects performed both tasks with and without response deadlines. The stimuli were presented foveally or unilaterally to one or the other hemisphere. With foveal presentations, the nominal-physical disparity disappeared when congruent and incongruent cells were compared, the fast-same effect occurred only in the shape task, and there was a preponderance of false-different errors only in the name task. Response times and error patterns from centrally presented trials conformed to the predictions of the model. Performance patterns from the lateralized trials conformed only partially. The implications of the data are discussed in the context of several theoretical models of same/different judgments.