Left Visual Field Right Hemisphere Research Articles

Lateralized reading in the healthy brain: A behavioral and computational study on the nature of the visual field effect

Despite its widespread use to measure functional lateralization of language in healthy subjects, the neurocognitive bases of the visual field effect in lateralized reading are still debated. Crucially, the lack of knowledge on the nature of the visual field effect is accompanied by a lack of knowledge on the relative impact of psycholinguistic factors on its measurement, thus potentially casting doubts on its validity as a functional laterality measure. In this study, an eye-tracking-controlled tachistoscopic lateralized lexical decision task (Experiment 1) was administered to 60 right-handed and 60 left-handed volunteers and word length, orthographic neighborhood, word frequency, and imageability were manipulated. The magnitude of visual field effect was bigger in right-handed than in left-handed participants. Across the whole sample, a visual field-by-frequency interaction was observed, whereby a comparatively smaller effect of word frequency was detected in the left visual field/right hemisphere (LVF/RH) than in the right visual field/left hemisphere (RVF/LH). In a subsequent computational study (Experiment 2), efficient (LH) and inefficient (RH) activation of lexical orthographic nodes was modelled by means of the Naïve Discriminative Learning approach. Computational data simulated the effect of visual field and its interaction with frequency observed in the Experiment 1. Data suggest that the visual field effect can be biased by word frequency. Less distinctive connections between orthographic cues and lexical/semantic output units in the RH than in the LH can account for the emergence of the visual field effect and its interaction with word frequency.

Laterality and (in)visibility in emotional face perception: Manipulations in spatial frequency content.

It is widely agreed that hemispheric asymmetries in emotional face perception exist. However, the mechanisms underlying this lateralization are not fully understood. In the present study, we tested whether (a) these asymmetries are driven by the low spatial frequency content of images depicting facial expressions, and (b) whether the effects differed depending on whether the emotional facial expressions were clearly visible or hidden (i.e., embedded in low spatial frequencies). The manipulation sheds light on the contribution of cortical and subcortical routes to emotional processing mechanisms. We prepared both unfiltered (broadband) and hybrid faces. Within the latter, different bands of spatial frequency content from images of 2 different expressions were combined (i.e., low frequencies from an emotional image combined with high frequencies from a neutral image). We presented these broadband and hybrid images using the free-viewing emotional chimeric faces task (ECFT) in which 2 images are presented above and below fixation and asked participants to report which of the 2 mirror reversed images appeared more emotional. As predicted, the results showed that only broadband expressions produced the well-known left visual field/right hemisphere (LVF/RH) bias across all basic emotions. For hybrid images, only happiness revealed a significant LVF/RH bias. These results suggest that low spatial frequency content of emotional facial expressions, which activates the magnocellular pathway in subcortical structures and bypassing cortical visual processing, is not generally sufficient to induce an LVF bias under free-viewing conditions where participants deny explicitly seeing the emotion, suggesting that the LVF bias in ECFT is primarily cortically mediated. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Interhemispheric transfer of semantic information facilitates bilateral word recognition.

Language comprehension is left-lateralized but with variable contributions from the right hemisphere. When both hemispheres are stimulated simultaneously using divided visual field presentation, performance may be enhanced or hindered depending on the complexity of the task, and these effects may relate to independent processing in both hemispheres or to information transfer between hemispheres. Simultaneous stimulation of both hemispheres is thought to suppress interhemispheric interactions, but information transfer may nonetheless occur. Studies with simultaneous bilateral displays have demonstrated that semantic information from the contralateral visual field (and hemisphere) can facilitate relatedness judgments and lexical decisions. The current study extends this line of research by assessing semantic information transfer in a bilateral word identification task. Task manipulations involving directed spatial attention and asymmetric primes (e.g., ATOM → BOMB) were used to isolate automatic priming as opposed to top-down processing. The results revealed 2 main findings: (a) interhemispheric priming in the form of improved word recognition occurred specifically in conditions designed to isolate automatic transfer of semantic information, that is, in the attended visual field for the target word in asymmetric prime pairs, and (b) there is evidence for an asymmetrical transfer of semantic information, in that the subordinate left visual field-right hemisphere benefited more from such transfer. Together, these results demonstrate evidence for automatic interhemispheric transfer of semantic information, even under conditions of simultaneous bilateral display. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Hemispheric processing in conventional metaphor comprehension: The role of general knowledge

This study explored the relation between general knowledge and the hemispheric processing of metaphoric expressions in college age students. We hypothesized that prior knowledge influences how the hemispheres process metaphors in these individuals. In this study, 97 young (college-aged) adults completed a general knowledge and vocabulary test, and were then divided into high-knowledge/high-vocabulary and low-knowledge/low-vocabulary groups. Next, participants viewed word pairs consisting of conventional metaphors, novel metaphors, word pairs with a literal meaning, and unrelated word pairs. The first word in each pair was presented centrally, and the second was presented to the right visual field-left hemisphere (rvf-LH) or the left visual field-right hemisphere (lvf-RH), and participants indicated whether each pair was a meaningful expression. Accuracy results showed an interaction between general knowledge and visual-field hemisphere. Low-knowledge participants were more accurate for metaphors presented to the rvf-LH than the lvf-RH, whereas high-knowledge participants showed no accuracy differences between the hemispheres. We also found an interaction between vocabulary and visual field-hemisphere for conventional metaphors. Specifically, low-vocabulary participants showed a left-hemisphere accuracy advantage, but high-vocabulary participants showed similar accuracy patterns in both hemispheres. These results suggest that young adult readers who have more general knowledge process conventional metaphors similarly in both hemispheres, whereas young adult readers who have less general knowledge may rely more heavily on left-hemisphere processes during conventional metaphor comprehension.

Attenuated hemispheric asymmetry in metaphor processing among adults with ADHD.

To characterize the hemispheric processing of metaphors in adults with ADHD compared to controls. We investigated the hemispheric processing of metaphors in 24 adult participants diagnosed with ADHD and 24 control participants. The hemispheric processing was examined using a divided visual field paradigm, in which different kinds of metaphors as well as literal word pairs and unrelated word pairs were presented either to the right visual field/left hemisphere (RVF/LH) or to the left visual field/right hemisphere (LVF/RH). Control participants processed metaphors more efficiently when presented in the LVF/RH than when presented in the RVF/LH, whereas participants with ADHD demonstrated attenuated asymmetry of hemispheric processing. Furthermore, asymmetry of hemispheric processing, together with sustained attention, contributed significantly to the prediction of self-report of ADHD symptoms. Our results suggest that the hemispheric processing of adults with ADHD is less lateralized than the hemispheric processing of control participants. Moreover, the diminished lateralization of metaphor processing along with deficient sustained attention may reflect distinct cognitive mechanisms underlying ADHD and as such our results support multiple pathway models of ADHD. (PsycINFO Database Record

Hemispheric processing of predictive inferences during reading: The influence of negatively emotional valenced stimuli

ABSTRACTAlthough a left hemisphere advantage is usually evident during language processing, the right hemisphere is highly involved during the processing of weakly constrained inferences. However, currently little is known about how the emotional valence of environmental stimuli influences the hemispheric processing of these inferences. In the current study, participants read texts promoting either strongly or weakly constrained predictive inferences and performed a lexical decision task to inference-related targets presented to the left visual field-right hemisphere or the right visual field-left hemisphere. While reading these texts, participants either listened to dissonant music (i.e., the music condition) or did not listen to music (i.e., the no music condition). In the no music condition, the left hemisphere showed an advantage for strongly constrained inferences compared to weakly constrained inferences, whereas the right hemisphere showed high facilitation for both strongly and weakly constrained inferences. In the music condition, both hemispheres showed greater facilitation for strongly constrained inferences than for weakly constrained inferences. These results suggest that negatively valenced stimuli (such as dissonant music) selectively influences the right hemisphere’s processing of weakly constrained inferences during reading.

Category Membership and Semantic Coding in the Cerebral Hemispheres

Although a gradient of category membership seems to form the internal structure of semantic categories, it is unclear whether the 2 hemispheres of the brain differ in terms of this gradient. The 2 experiments reported here examined this empirical question and explored alternative theoretical interpretations. Participants viewed category names centrally and determined whether a closely related or distantly related word presented to either the left visual field/right hemisphere (LVF/RH) or the right visual field/left hemisphere (RVF/LH) was a member of the category. Distantly related words were categorized more slowly in the LVF/RH relative to the RVF/LH, with no difference for words close to the prototype. The finding resolved past mixed results showing an unambiguous typicality effect for both visual field presentations. Furthermore, we examined items near the fuzzy border that were sometimes rejected as nonmembers of the category and found both hemispheres use the same category boundary. In Experiment 2, we presented 2 target words to be categorized, with the expectation of augmenting the speed advantage for the RVF/LH if the 2 hemispheres differ structurally. Instead the results showed a weakening of the hemispheric difference, arguing against a structural in favor of a processing explanation.

Hemispheric processing of mental representations during text comprehension: Evidence for inhibition of inconsistent shape information

To successfully understand a text, readers often mentally represent the shape of an object described in a text (e.g., creating a mental image of a sliced tomato when reading about a tomato on a pizza). However, it is currently unclear how the cerebral hemispheres contribute to these mental images during reading. In the current study, participants were presented with sentences consistent with the shape of an object (i.e., the match condition), sentences inconsistent with the shape of an object (i.e., the mismatch condition), or sentences that did not specify the shape of an object (i.e., the neutral condition). Participants read each sentence and then viewed an image of an object that was quickly presented to either the right visual field-left hemisphere (rvf-LH) or the left visual field-right hemisphere (lvf-RH). Results indicate that when the shape of an object was implicitly described in the text (in Experiment 1), response times for images presented to the rvf-LH were longer in the mismatch condition than in the neutral or match conditions. However, no response time differences were evident in the lvf-RH. When the shape of an object was explicitly described in the text (in Experiment 2), response times were longer in the mismatch condition than in the neutral and match conditions in both hemispheres. Thus, hemispheric involvement in mental representation depends on how explicit information is described in a text. Furthermore, these findings suggest that readers inhibit information that does not match an object׳s shape described in a text.

Exploring the relationship between response time, sensitivity and bias in categorical and coordinate visuospatial processes: Evidence for hemispheric specialisation

Right visual field-left hemisphere (RVF-LH) and left visual field-right hemisphere (LVF-RH) specialisations found for categorical and coordinate visuospatial judgements, respectively, are thought to demonstrate two different perceptual processes. In the current experiment, we used signal detection theory to investigate categorical and coordinate processes, and to explore the relationship between response time (RT), sensitivity and bias measures. We found a LVF-RH advantage for the processing of categorical spatial relations when this effect was indexed by sensitivity. We also found that task influenced response bias in RVF-LH trials, but not in LVF-RH trials. Increased sensitivity was correlated with faster responses in the coordinate task but slower responses in the categorical task, and faster RTs when responding liberally in RVF-LH but not LVF-RH categorical trials. By analysing signal detection measures alongside RT, the findings suggest that differences in sensitivity and response bias may contribute to typical task by hemisphere effects in RT.

Poster #S100 NEUROCOGNITION, SOCIAL COGNITION AND THREE-YEAR FOLLOW-UP SOCIAL FUNCTIONING IN RECENT VERSUS NON-RECENT ONSET PSYCHOSIS

Recent evidence suggests that certain types of figurative language, such as conventional metaphors or idioms, may have a left hemisphere processing advantage or are processed similarly in both hemispheres. Sarcasm, however, is likely processed differently than other types of figurative language in the hemispheres because readers often need to construct a novel interpretation of sarcastic text to successfully understand the text’s sarcastic meaning. To investigate how the hemispheres process sarcasm during text comprehension, participants in the current study read sarcastic, literal, and neutral texts and made lexical decisions to related target words presented to either the left visual field-right hemisphere or the right visual field-left hemisphere. Facilitation for sarcastic texts was greater in the right hemisphere than the left hemisphere. In addition, facilitation was greater for literal texts than sarcastic texts in the left hemisphere. These findings suggest that the right hemisphere may play a unique role when readers encounter sarcasm during text comprehension.

Hemispheric processing of idioms: The influence of familiarity and ambiguity

Recent findings suggest that the right hemisphere plays a key role when readers comprehend figurative language. However, it is currently unclear how specific types of figurative language, such as idioms (e.g., “to bury the hatchet”), are processed in the right and left cerebral hemispheres. Prior research suggests that a reader's previous exposure to an idiomatic phrase (i.e., the level of familiarity) and the plausibility of an idiom (i.e., the level of ambiguity) influence how idioms are processed. To investigate how familiarity influences the hemispheric processing of idioms (Experiment 1), participants read texts containing familiar or less familiar idioms and made lexical decisions to related target words presented to the left visual field-right hemisphere or to the right visual field-left hemisphere. To investigate how ambiguity influences the hemispheric processing of idioms (Experiment 2), participants read texts containing high or low ambiguity idioms and completed a lexical decision task to related target words presented to each visual field-hemisphere. For both familiar and less familiar idioms, greater facilitation was evident in the left hemisphere than in the right hemisphere. Additionally, greater facilitation was evident in the left hemisphere for low ambiguity idioms than for high ambiguity idioms, and greater facilitation was evident in the right hemisphere for high ambiguity idioms than for low ambiguity idioms. These findings suggest that the right hemisphere has an advantage when readers process ambiguous idioms, whereas the left hemisphere has an advantage when readers process low ambiguity idioms, and both familiar and less familiar idioms. • We explored hemispheric processing of idioms (high versus low familiarity; high versus low ambiguity). • Using divided visual field, participants read idiomatic texts and viewed related target words. • We observed left hemisphere advantages for high and low familiarity and low ambiguity idioms. • We also observed a right hemisphere advantage for high ambiguity idioms. • We conclude that the hemispheres process idioms differently based on the level of idiom ambiguity.

Novel Word Processing

People who text messages often shorten words by eliminating internal letters (e.g., "climate, clmte"). Although these novel representations (i.e., subset word forms) are not true words, sentence context may prime semantic activation. We hypothesized that if participants are presented with a context sentence prime containing a subset form target word, then participants' performance should improve when the stimulus is presented to the left visual field/right hemisphere (LVF/RH) because the RH is less reliant on correct orthography than the left hemisphere (LH). We also hypothesized that participants' bias of processing novel stimuli is a function of visual field and hemisphere presentation. The results supported the hypothesis. When participants were shown subset word forms in the LVF/RH, their accuracy was significantly greater than when they were shown in the RVF/LH. Additionally, signal detection theory was applied to the results and substantiated the findings that participants' bias toward processing subset and orthographically correct words is a function of visual field and hemisphere presentation.

Electrophysiological evidence for the action of a center-surround mechanism on semantic processing in the left hemisphere.

Physiological evidence was sought for a center-surround attentional mechanism (CSM), which has been proposed to assist in the retrieval of weakly activated items from semantic memory. The CSM operates by facilitating strongly related items in the “center” of the weakly activated area of semantic memory, and inhibiting less strongly related items in its “surround”. In this study weak activation was created by having subjects acquire the meanings of new words to a recall criterion of only 50%. Subjects who attained this approximate criterion level of performance were subsequently included in a semantic priming task, during which ERPs were recorded. Primes were newly learned rare words, and targets were either synonyms, non-synonymously related words, or unrelated words. All stimuli were presented to the RVF/LH (right visual field/left hemisphere) or the LVF/RH (left visual field/right hemisphere). Under RVF/LH stimulation the newly learned word primes produced facilitation on N400 for synonym targets, and inhibition for related targets. No differences were observed under LVF/RH stimulation. The LH thus, supports a CSM, whereby a synonym in the “center” of attention, focused on the newly learned word, is facilitated, whereas a related word in the “surround” is inhibited. The data are consistent with the view of this laboratory that semantic memory is subserved by a spreading activation system in the LH. Also consistent with our view, there was no evidence of spreading activation in the RH. The findings are discussed in the context of additional recent theories of semantic memory. Finally, the adult right hemisphere may require more learning than the LH in order to demonstrate evidence of meaning acquisition.

Hemispheric inference priming during comprehension of conversations and narratives

In this study we examined asymmetric semantic activation patterns as people listened to conversations and narratives that promoted causal inferences. Based on the hypothesis that understanding the unique features of conversational input may benefit from or require a modified pattern of conceptual activation during conversation, we compared semantic priming in both hemispheres for inferences embedded in conversations and in narratives. Participants named inference-related target words or unrelated words presented to the left visual field-right hemisphere (lvf-RH) or to the right visual field-left hemisphere (rvf-LH) at critical coherence points that required an inference in order to correctly understand an utterance in the context of the conversation or narrative. Fifty-seven undergraduates listened to 36 conversations or narratives and were tested at 100 target inference points. During narrative comprehension, inference-related priming was reliable and equally strong in both hemispheres. In contrast, during conversation comprehension, inference-related priming was only reliable for target words presented to lvf-RH. This work demonstrates that priming for inference-related concepts can be measured with input in conversational form and suggests the language processing style of the RH is advantageous for comprehending conversation.

Hemispheric processing of sarcastic text

Recent evidence suggests that certain types of figurative language, such as conventional metaphors or idioms, may have a left hemisphere processing advantage or are processed similarly in both hemispheres. Sarcasm, however, is likely processed differently than other types of figurative language in the hemispheres because readers often need to construct a novel interpretation of sarcastic text to successfully understand the text’s sarcastic meaning. To investigate how the hemispheres process sarcasm during text comprehension, participants in the current study read sarcastic, literal, and neutral texts and made lexical decisions to related target words presented to either the left visual field-right hemisphere or the right visual field-left hemisphere. Facilitation for sarcastic texts was greater in the right hemisphere than the left hemisphere. In addition, facilitation was greater for literal texts than sarcastic texts in the left hemisphere. These findings suggest that the right hemisphere may play a unique role when readers encounter sarcasm during text comprehension.

Metaphoric advertisement comprehension: The role of the cerebral hemispheres

AbstractCurrently little is known about how implicit processes (i.e., cognitive processes that consumers are unaware of) are utilized as consumers read metaphoric advertisements. The field of cognitive neuroscience can help marketers better understand consumers' implicit processing by examining how each cerebral hemisphere uniquely contributes during metaphoric advertisement comprehension. A right hemisphere advantage has been demonstrated during metaphoric language processing; however, it is unclear how each hemisphere of the brain processes metaphors used in advertisements. This study combines the fields of marketing and cognitive neuroscience to investigate the hemispheric processing of metaphoric advertisements. Through the use of the divided visual field paradigm, participants read metaphor, literal, or neutral slogans and responded to related target words presented to either the left visual field‐right hemisphere or the right visual field‐left hemisphere. As predicted, there was a right hemisphere advantage, compared to the left hemisphere, for metaphoric slogans. Additionally, greater facilitation was evident in the right hemisphere for literal slogans compared to metaphoric slogans. Metaphoric messages were also remembered better than literal ones. These findings provide an in‐depth account of how consumers implicitly process messages, suggesting an important role of the right hemisphere during the comprehension of both metaphoric and literal messages. Copyright © 2011 John Wiley & Sons, Ltd.

Emotional valence and arousal effects on memory and hemispheric asymmetries

This study examined predictions based upon the right hemisphere (RH) model, the valence–arousal model, and a recently proposed integrated model ( Killgore & Yurgelun-Todd, 2007) of emotion processing by testing immediate recall and recognition memory for positive, negative, and neutral verbal stimuli among 35 right-handed women. Building upon methodologies of previous studies, we found that words presented to the right visual field/left hemisphere (RVF/LH) were recalled and recognized more accurately than words presented to the left visual field/right hemisphere (LVF/RH), and we found significant valence by visual field interactions. Some findings were consistent with one of the models evaluated whereas others were consistent with none of the models evaluated. Our findings suggest that an integration of the RH and valence–arousal models may best account for the findings with regard to hemispheric lateralization of memory for emotional stimuli.

Event-related potentials reveal the effects of aging on meaning selection and revision.

ERPs were recorded as older adults decided if a target word was related to a lateralized ambiguous or unambiguous prime; prime-target pairs were preceded by a related or unrelated context word. In an unrelated context, N400 facilitation effects differed from those seen in young adults, with older adults showing priming for the dominant meaning (e.g., BOOM-BANK-DEPOSIT) on right visual field/left hemisphere (RVF/LH) trials and priming for the subordinate meaning (e.g., BOOM-BANK-RIVER) on LVF/RH trials. Higher-functioning older adults, especially those with better inhibition, were more likely to show bilateral activation of the dominant meaning and unilateral activation of the subordinate meaning, suggesting a retention of young-like activation. In a biasing context (e.g., RIVER-BANK-DEPOSIT), older adults selected the contextually-consistent meaning, but were less likely than young adults to revise their selection.

Categorical perception of color is lateralized to the right hemisphere in infants, but to the left hemisphere in adults

Both adults and infants are faster at discriminating between two colors from different categories than two colors from the same category, even when between- and within-category chromatic separation sizes are equated. For adults, this categorical perception (CP) is lateralized; the category effect is stronger for the right visual field (RVF)-left hemisphere (LH) than the left visual field (LVF)-right hemisphere (RH). Converging evidence suggests that the LH bias in color CP in adults is caused by the influence of lexical color codes in the LH. The current study investigates whether prelinguistic color CP is also lateralized to the LH by testing 4- to 6-month-old infants. A colored target was shown on a differently colored background, and time to initiate an eye movement to the target was measured. Target background pairs were either from the same or different categories, but with equal target-background chromatic separations. Infants were faster at initiating an eye movement to targets on different-category than same-category backgrounds, but only for targets in the LVF-RH. In contrast, adults showed a greater category effect when targets were presented to the RVF-LH. These results suggest that whereas color CP is stronger in the LH than RH in adults, prelinguistic CP in infants is lateralized to the RH. The findings suggest that language-driven CP in adults may not build on prelinguistic CP, but that language instead imposes its categories on a LH that is not categorically prepartitioned.

大域優先性効果に対してラテラリティが及ぼす影響―干渉効果を中心に―

This study aimed to clarify the influence of laterality on interference effects for global precedence, and to examine the mechanism of these effects. In most previous studies, the neutral condition was excluded from the consistency factor and the difference of latencies between the consistent and inconsistent conditions was regarded as the interference score, which may not be accurate. In this study, the difference of latencies between the neutral and the inconsistent condition was regarded as the interference score. The results of the analysis of variance (ANOVA) for latencies showed that interference effects influenced only right visual field-left hemisphere (RVF-LH), and facilitation effects influenced only left visual field-right hemisphere (LVF-RH) in the local condition. These findings indicate that it does not matter how optimal processing influenced interference effects on suboptimal processing in each hemisphere, for example how global processing influenced local processing in the right hemisphere, but rather how each hemisphere controlled optimal processing.