Divided Visual Field Paradigm Research Articles

Hemispheric functional asymmetries and sex effects in visual bistable perception

This study investigates bistable perception as a function of the presentation side of the ambiguous figures and of participants’ sex, to evaluate left–right hemispheric (LH-RH) asymmetries related to consciousness. In two experiments using the divided visual field paradigm, two Rubin's vase-faces figures were projected simultaneously and continuously 180 s long to the left (LVF) and right (RVF; Experiment 1) or to the upper (UVF) and lower (DVF; Experiment 2) visual hemifields of 48 healthy subjects monitored with eye-tracker. Experiment 1 enables stimulus segregation from the LVF to the RH and from the RVF to the LH, whereas Experiment 2 does not. Results from Experiment 1 show that males perceived the face profiles for more time in the LVF than in the RVF, with an opposite trend for the vase, whereas females show a similar pattern of perception in the two hemifields. A related result confirmed the previously reported possibility to have simultaneously two different percepts (qualia) in the two hemifields elicited by the two identic ambiguous stimuli, which was here observed to occur more frequently in males. Similar effects were not observed in Experiment 2. These findings suggest that the percepts display the processing abilities of the hemisphere currently processing the stimulus eliciting them (e.g., RH-faces), and that females and males reflect in bistable perception, a genuine manifestation of consciousness, the well-known hemispheric asymmetry differences they show in ordinary perception.

Processing objects of perceptual expertise: Differential interhemispheric transmission efficiency but similar transmission direction advantages

Faces and Chinese characters are both objects of perceptual expertise. In this study, we investigated the characteristics of interhemispheric transmission times (IHTTs) in both transmission direction and transmission efficiency during the processing of objects of perceptual expertise. A total of 112 participants engaged in a divided visual field paradigm for faces, Chinese characters, and houses in both upright and inverted orientations. The N170 amplitudes elicited by the objects of perceptual expertise (faces and Chinese characters) involved in this study were larger than those elicited by the non-perceptual expertise objects (houses). We used the latencies of the N170 component of the event-related potential (ERP) recorded in the left and right hemispheres to calculate the IHTTs. For all objects, the N170-related IHTTs from the right to the left hemispheres were shorter than those in the opposite direction. Essentially, the N170-related IHTTs for faces were shorter, that is, more efficient than those for Chinese characters and houses. This result indicates that the IHTTs during perceptual expertise and non-perceptual expertise object processing share a common transmission direction advantage, but transmission efficiency is face-specific.

Lateralization of word and face processing in developmental dyslexia and developmental prosopagnosia

In right-handed adults, face processing is lateralized to the right hemisphere and visual word processing to the left hemisphere. According to the many-to-many account (MTMA) of functional cerebral organization this lateralization pattern is partly dependent on the acquisition of literacy. Hence, the MTMA predicts that: (i) processing of both words and faces should show no or at least less lateralization in individuals with developmental dyslexia compared with controls, and (ii) lateralization in word processing should be normal in individuals with developmental prosopagnosia whereas lateralization in face processing should be absent. To test these hypotheses, 21 right-handed adults with developmental dyslexia and 21 right-handed adults with developmental prosopagnosia performed a divided visual field paradigm with delayed matching of faces, words and cars. Contrary to the predictions, we find that lateralization effects in face processing are within the normal range for both developmental dyslexics and prosopagnosics. Moreover, the group with developmental dyslexia showed right hemisphere lateralization for word processing. We argue that these findings are incompatible with the specific predictions of the MTMA.

Task-domain and hemisphere-asymmetry effects in cisgender and transmale individuals.

The present research examined the extent to which transmale individuals’ functional brain organization resembles that of their assigned sex or gender identity. Cisgender-female, cisgender-male, and transmale participants, who were assigned female sex but did not have a female gender identity, were compared in terms of effects that have been observed in cisgender individuals: task-domain effects, in which males perform better than females on spatial tasks and females perform better than males on verbal tasks; and hemisphere-asymmetry effects, in which males show larger differences between the left and right hemispheres than females. In addition, the present research measured participants’ intelligence in order to control for potential moderating effects. Participants performed spatial (mental rotation) and verbal (lexical decision) tasks presented to each hemisphere using a divided-visual field paradigm, and then completed an intelligence assessment. In the mental-rotation task, cismale and transmale participants performed better than cisfemale participants, however this group difference was explained by intelligence scores, with higher scores predicting better performance. In the lexical-decision task, cismale and transmale participants exhibited a greater left-hemisphere advantage than cisfemales, and this difference was not affected by intelligence scores. Taken together, results do not support task-domain effects when intelligence is accounted for; however, they do demonstrate a hemisphere-asymmetry effect in the verbal domain that is moderated by gender identity and not assigned sex.

Left Hemisphere Dominance for Negative Facial Expressions: The Influence of Task.

Major theories of hemisphere asymmetries in facial expression processing predict right hemisphere dominance for negative facial expressions of disgust, fear, and sadness, however, some studies observe left hemisphere dominance for one or more of these expressions. Research suggests that tasks requiring the identification of six basic emotional facial expressions (angry, disgusted, fearful, happy, sad, and surprised) are more likely to produce left hemisphere involvement than tasks that do not require expression identification. The present research investigated this possibility in two experiments that presented six basic emotional facial expressions to the right or left hemisphere using a divided-visual field paradigm. In Experiment 1, participants identified emotional expressions by pushing a key corresponding to one of six labels. In Experiment 2, participants detected emotional expressions by pushing a key corresponding to whether an expression was emotional or not. In line with predictions, fearful facial expressions exhibited a left hemisphere advantage during the identification task but not during the detection task. In contrast to predictions, sad expressions exhibited a left hemisphere advantage during both identification and detection tasks. In addition, happy facial expressions exhibited a left hemisphere advantage during the detection task but not during the identification task. Only angry facial expressions exhibited a right hemisphere advantage, and this was only observed when data from both experiments were combined. Together, results highlight the influence of task demands on hemisphere asymmetries in facial expression processing and suggest a greater role for the left hemisphere in negative expressions than predicted by previous theories.

Brain lateralization of face recognition in hearing-impairedindividuals

<p indent=0mm>Adults show the left-visual field/right-hemisphere advantage for the recognition of face. The experience of auditory deprivation and sign language in hearing-impaired individuals could reshape the function and structure of brain. Previous studies suggest that hearing-impaired individuals demonstrate the right-visual field or left-hemisphere superiority for visuospatial attention, visual motion information processing and facial expression processing. The present study aims to further investigate the brain lateralization for face processing in hearing-impaired adults by using behavioral and ERP measures. In experiment 1, the divided visual field paradigm was used and the accuracies and corrected reaction times of face processing in the left-visual field were found to be significantly higher and shorter than those in the right-visual field for hearing individuals, whereas there were no significant differences between left- and right-visual field in hearing-impaired individuals. However, both hearing and hearing-impaired individuals showed the same left-visual field superiority for word processing efficiency. In experiment 2, One-back task and ERPs were used to investigate the brain lateralization of face recognition in hearing and hearing-impaired individuals. The results showed that the N170 amplitude for face processing in the right hemisphere was significantly larger than that in the left hemisphere for hearing individuals. However, there was no significant difference in N170 amplitude between the left and right hemispheres for hearing-impaired individuals. As for word processing, hearing and hearing-impaired individuals both showed a bilateral activation. Therefore, the current study provided converging evidence that the left-visual field or right hemisphere superiority for face processing in hearing-impaired individuals disappeared. These findings not only expand our understanding of the face processing in hearing-impaired individuals, but also help us understand the hemispheric organization for face recognition.

An Electrophysiological Abstractness Effect for Metaphorical Meaning Making.

Neuroimaging studies show that metaphors activate sensorimotor areas. These findings were interpreted as metaphors contributing to conceptual thought by mapping concrete, somatosensory information onto abstract ideas. But is sensorimotor information a necessary constituent of figurative meaning? The present study employed event-related potentials (ERPs) in a divided visual field paradigm with healthy adults to explore the role of sensorimotor feature processing in the comprehension of novel metaphors via the electrophysiological concreteness effect. Participants read French, novel adjective-noun expressions that were either metaphorical (“fat sentence”) or literal (“fat hip”). While literal expressions evoked a typical concreteness effect, an enhanced frontal negativity during right hemisphere (RH) as opposed to left hemisphere (LH) presentation, metaphors showed no such sign of sensorimotor feature processing. Relative to literals, they evoked a sustained frontal negativity during LH presentation and similar amplitudes during RH presentation, but both of these effects were the greater the more abstract the metaphors were. It is the first time such an electrophysiological abstractness effect is reported, just the opposite of a concreteness effect. It is particularly noteworthy that ERPs evoked by metaphors were not contingent on figurativeness, novelty, meaningfulness, imageability, emotional valence, or arousal, only on abstractness. When compared with similarly novel literal expressions, metaphors did not evoke a typical N400 and did not activate the RH either. The findings shed new light on the neurocognitive machinery of figurative meaning construction, pervasive in everyday communication. Contrary to embodied cognition, the conceptual system might be organized around abstract representations and not sensorimotor information, even for lush, metaphorical language.

Hemispheric processing of predictive inferences: the effects of textual constraint and metacomprehension monitoring competence

Previous research into predictive inferences making showed that textual constraint influenced hemispheric processing of the inferences. However, the relationship between metacomprehension monitoring competence (MMC) and hemispheric processing of predictive inferences has rarely been investigated. The present study employed a divided visual field (DVF) paradigm to examine the effects of textual constraint and MMC on hemispheric processing of predictive inferences with Chinese native speakers during Chinese text reading. Results showed that neither response time nor facilitation effects indicated any significant interaction for our MMC groups. MMC was unlikely to play a role in hemispheric processing of predictive inferences. The results were consistent with those of the very rare relevant previous research, in which readers’ judgments of learning failed to have significant effects on inference making performance while judgments of inferencing had. Future investigation could focus more on the study of an inference-specific dimension of metacomprehension monitoring that might be more closely related to inference making. Results also indicated that the left hemisphere (LH) showed greater facilitation for strongly constrained predictive inferences than for weakly constrained predictive inferences, and that the right hemisphere (RH) showed greater levels of facilitation for weakly constrained predictive inferences. Taken together, MMC did not seem to have a positive impact on hemispheric predictive inference making. There was a RH facilitation advantage for weakly constrained texts and an LH advantage for strongly constrained texts.

Independent perceptual reversals for simultaneously presented ambiguous figures.

In two successive experiments using the divided visual field paradigm with vertical or horizontal division, two ambiguous figures, the Rubin's vase-face or the Necker cube, were projected to the right and left or to the upper and lower visual hemifields of 108 healthy volunteers. Stimulation time was 120s. The main hypotheses were (a) that different percepts of the same ambiguous figure may be simultaneously experienced in the two hemifields and (b) that the type (vertical vs. horizontal) of visual field division influences the reversal frequency and the temporal interdependence of the percepts. Results from the first experiment showed that the temporal interdependence of reversals was very low for both ambiguous figures, suggesting that during part of the stimulation time the subjects could experience different percepts of the same figure (e.g. a vase in the right and face profiles in the left visual hemifields). The second experiment showed that this perceptual dissociation occurred on average during one third of the stimulation time. In both experiments the type of visual field division did not influence either frequency or temporal interdependence of the reversals. When one single ambiguous figure was presented in the centre of the screen, the number of reversals was approximately the sum of the reversals observed with two figures presented simultaneously each in one hemifield.

Emotion Words' Effect on Visual Awareness and Attention of Emotional Faces.

To explore whether the meaning of a word changes visual processing of emotional faces (i.e., visual awareness and visual attention), we performed two complementary studies. In Experiment 1, we presented participants with emotion and control words and then tracked their visual awareness for two competing emotional faces using a binocular rivalry paradigm. Participants experienced the emotional face congruent with the emotion word for longer than a word-incongruent emotional face, as would be expected if the word was biasing awareness toward the (unseen) face. In Experiment 2, we similarly presented participants with emotion and control words prior to presenting emotional faces using a divided visual field paradigm. Emotion words were congruent with either the emotional face in the right or left visual field. After the presentation of faces, participants saw a dot in either the left or right visual field. Participants were slower to identify the location of the dot when it appeared in the same visual field as the emotional face congruent with the emotion word. The effect was limited to the left hemisphere (RVF), as would be expected for linguistic integration of the word with the face. Since the task was not linguistic, but rather a simple dot-probe task, participants were slower in their responses under these conditions because they likely had to disengage from the additional linguistic processing caused by the word-face integration. These findings indicate that emotion words bias visual awareness for congruent emotional faces, as well as shift attention toward congruent emotional faces.

Right hemisphere involvement for pun processing – Effects of idiom decomposition

Abstract The present study investigated hemispheric processing of puns involving decomposable idioms (e.g. Old skiers never die, they just go downhill) and non-decomposable ones (e.g., Old cleaners never die, they just bite the dust) using a divided visual field paradigm. In two cross-modal priming experiments, participants listened to puns and made lexical decisions for targets presented either in the left or right visual fields. To investigate hemispheric asymmetries at different processing stages (early vs. late), the prime-target inter-stimulus interval was 0 ms in Experiment 1 and was increased to 750 ms in Experiment 2. The results from both experiments demonstrated a left hemisphere advantage for processing puns triggered by non-decomposable idioms; puns motivated by decomposable idioms were processed equally fast in both hemispheres, suggesting that this type of pun induced right hemisphere involvement and led to bilateral processing. We discuss the results in light of predictions derived from the ‘graded salience’ hypothesis and the ‘fine-coarse coding’ hypothesis and argue that the data are more consistent with the graded salience hypothesis.

Lateralized Affective Word Priming and Gender Effect.

Affective priming research suggests that processing of affective words is a quick and short lived process. Using the divided visual field (DVF) paradigm, investigations of the lateralization of affective word processing have yielded inconsistent results. However, research on semantic processing of words generally suggests that the left hemisphere (LH) is the location where rapid processing occurs. We investigated the processing of affective (emotional) words using a combination of the DVF and affective priming paradigms, and four stimulus onset asynchronies (SOAs)—0, 150, 300, and 750 ms. The priming pattern yielded by males (n = 32) showed quick priming (at 0-ms SOA) of affective words in the LH; there was slower right hemisphere (RH) priming of affective words (at 750-ms SOA). In females (n = 28), both hemispheres were associated with quick priming of affective words (at 300-ms SOA in the LH and at 150-ms SOA in the RH). Results demonstrate the capability of both cerebral hemispheres in the processing of words with affective meaning, along with leading role of the left hemisphere in this process. This is similar to the results of semantic research that suggest access to word meanings occurs in both hemispheres, but different mechanisms might be involved. While the LH seems to prime affective words quickly regardless of gender, gender differences are likely in the RH in that affective word processing probably occurs slowly in males but rapidly in females. This gender difference may result from increased sensitivity to the emotional feature of affective words in females.

Hemispheric processing of lexical information in Chinese character recognition and its relationship to reading performance

Hemispheric predominance has been well documented in the visual perception of alphabetic words. However, the hemispheric processing of lexical information in Chinese character recognition and its relationship to reading performance are far from clear. In the divided visual field paradigm, participants were required to judge the orthography, phonology, or semantics of Chinese characters, which were presented randomly in the left or right visual field. The results showed a right visual field/left hemispheric superiority in the phonological judgment task, but no hemispheric advantage in the orthographic or semantic task was found. In addition, reaction times in the right visual field for phonological and semantic tasks were significantly correlated with the reading test score. These results suggest that both hemispheres involved in the orthographic and semantic processing of Chinese characters, and that the left lateralized phonological processing is important for Chinese fluent reading.

The Own-Race Bias and the cerebral hemispheres

ABSTRACTThe Own-Race Bias (ORB) is the ability to better recognize and categorize a face when the depicted person belongs to the observer’s ethnicity group. The relationship between the ORB and hemispheric asymmetries has been poorly explored, and the present study was aimed at investigating this relationship, as well as that between the ORB and the bias to better recognize own gender faces. Female and male Caucasian participants categorized the ethnicity of Caucasian and Asian female and male facial stimuli in a divided visual field paradigm. In a control experiment the same stimuli were presented centrally, confirming the ORB. Importantly, the lateralized presentation reversed the bias with higher accuracy and shorter response times in the categorization of Asian than Caucasian faces. This reversed bias was significant for female and male faces, and it was observed when stimuli were presented in the left but not in the right visual field, revealing the crucial role of the right hemisphere in face processing. These results shed new light on the hemispheric abilities in the categorization of facial features, and they are compared to previous evidence of cerebral asymmetries for facial age, gender and identity, both in healthy participants and in neurological patients.

Increased reliance on a right hemispheric mechanism during idiom processing in adults with dyslexia

ABSTRACTPrevious studies on adults with dyslexia (DYS) have indicated difficulties in the comprehension of figurative language. Using the divided visual field paradigm, the present study investigated the hemispheric processing of idioms among 22 adults with DYS and 21 regular reader (RR) adults. Participants performed a lexical decision task for a target word related to either a literal or a figurative interpretation of an idiom. The results show that whereas the RR group demonstrated a bilateral pattern of hemispheric processing of idiomatic meanings, the DYS group showed a right hemisphere (RH) advantage. Furthermore, both groups demonstrated the typical RH advantage in processing the literal meanings of idioms. Our findings indicate increased recruitment of the RH in dyslexia, probably due to differences in cerebral language areas or weaker LH semantic processing.

Individual Differences and Hemispheric Asymmetries for Language and Spatial Attention.

Language and spatial processing are cognitive functions that are asymmetrically distributed across both cerebral hemispheres. In the present study, we compare left- and right-handers on word comprehension using a divided visual field paradigm and spatial attention using a landmark task. We investigate hemispheric asymmetries by assessing the participants’ behavioral metrics; response accuracy, reaction time and their laterality index. The data showed that right-handers benefitted more from left-hemispheric lateralization for language comprehension and right-hemispheric lateralization for spatial attention than left-handers. Furthermore, left-handers demonstrated a more variable distribution across both hemispheres, supporting a less focal profile of functional brain organization. Taken together, the results underline that handedness distinctively modulates hemispheric processing and behavioral performance during verbal and nonverbal tasks. In particular, typical lateralization is most prevalent for right-handers whereas atypical lateralization is more evident for left-handers. These insights contribute to the understanding of individual variation of brain asymmetries and the mechanisms related to changes in cerebral dominance.

One is all you need: intrahemispheric processing benefits nonverbal visual recognition

ABSTRACTSeveral attempts have been made to understand when and how the two hemispheres of the brain work together to encode and retrieve information during memory tasks, but it remains unclear whether they are equally capable of encoding and retrieval, particularly when the stimuli do not evoke a leftward processing asymmetry. Using a divided visual field paradigm, we presented nonverbal visual stimuli to one visual field/hemisphere at encoding, and at retrieval presented the stimuli either to the same or opposite visual field/hemisphere. Recognition responses were faster and more accurate when the stimuli were initially presented at encoding and retrieval to the same hemisphere (Experiment 1), even when delay intervals between study and test were short (Experiment 2). Taken together, these findings suggest that recognition decisions for stimuli initially presented to a single hemisphere occur more quickly at shorter lags, perhaps due to a stronger memory representation in the original hemisphere of input compared to the indirectly activated hemisphere. Our results are significant because they demonstrate that each hemisphere of the brain can function to encode and retrieve memory representations equally well, as long as the stimuli contain no linguistic information.

When is the right hemisphere holistic and when is it not? The case of Chinese character recognition

Holistic processing (HP) has long been considered a characteristic of right hemisphere (RH) processing. Indeed, holistic face processing is typically associated with left visual field (LVF)/RH processing advantages. Nevertheless, expert Chinese character recognition involves reduced HP and increased RH lateralization, presenting a counterexample. Recent modeling research suggests that RH processing may be associated with an increase or decrease in HP, depending on whether spacing or component information was used respectively. Since expert Chinese character recognition involves increasing sensitivity to components while deemphasizing spacing information, RH processing in experts may be associated with weaker HP than novices. Consistent with this hypothesis, in a divided visual field paradigm, novices exhibited HP only in the LVF/RH, whereas experts showed no HP in either visual field. This result suggests that the RH may flexibly switch between part-based and holistic representations, consistent with recent fMRI findings. The RH’s advantage in global/low spatial frequency processing is suggested to be relative to the task relevant frequency range. Thus, its use of holistic and part-based representations may depend on how attention is allocated for task relevant information. This study provides the first behavioral evidence showing how type of information used for processing modulates perceptual representations in the RH.

DiViDu – An Open Source Solution for Dual Task Experiments with Integrated Divided Visual Field Paradigm

We here present DiViDu, a research software, which we developed for a dual task experiment with an integrated divided visual field paradigm. The dual task experiment consists of a lexical decision task with different semantic verb categories, and a complex tapping task with either the left or right hand. The software allows researchers the replication of our experiment, as well as the reconfiguration for further dual task experiments with alternative tapping tasks and stimuli (e.g., word classes, semantic classes, task languages) as well as adjusted experimental settings. Furthermore, with only slight modifications to the source code, researchers can implement various new experimental setups including a large variety of language tasks (e.g., silent and aloud reading, naming, verbal fluency) and non-verbal tasks. The software DiViDu is implemented using the .NET framework and is available under the Apache 2 License on GitHub ( https://github.com/dividu/dividu ). Funding statement: The publication of the paper was supported by the Open Access Publication Fund of the University of Konstanz.

Developmental changes in hemispheric processing of ambiguous words during adolescence

Abstract Previous research has provided evidence of a hemispheric asymmetry in processing dominant and subordinate associations of ambiguous words. However, developmental changes of this hemispheric asymmetry have been little studied. We used the divided visual field paradigm to examine the pattern of hemispheric involvement in ambiguity resolution in 31 Hebrew-speaking adolescents and 41 young adults. Participants performed a semantic judgement task on word pairs, where the first word was an ambiguous word (presented centrally) and the second word was related to either its dominant or subordinate meaning (presented laterally after a 750 ms stimulus onset asynchrony). In both groups, no difference was found between the visual fields performance in the dominant meaning condition. However, in the subordinate meaning condition, adolescents (but not adults) responded slower in the left visual field/right hemisphere. These results suggest that the role of RH in the broader semantic search of distant meanings become refined over adolescence, which might be related to the significant development of figurative language during this period. This study may extend the scope of the Fine-Coarse Semantic Coding Theory by including a developmental perspective.