Visual Field Left Hemisphere Research Articles

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.

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.

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.

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 inferences during text comprehension: The role of consistency and task difficulty

Although the hemispheres likely carry out different processes during reading, currently little is known about how the consistency effect and the difficulty of the task influences hemispheric processing during text comprehension. In the current study participants read texts promoting an inference, 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. To manipulate the consistency of information targets were either consistent or inconsistent with the inference. To manipulate difficulty the antecedent and its referent were either separated by two sentences (i.e., the less-difficult condition) or four sentences (i.e., the more-difficult condition). In the consistent condition facilitation was greater in the left hemisphere than the right hemisphere. In the inconsistent condition facilitation was greater in the right hemisphere than the left hemisphere. When analyses were combined across conditions, consistent targets showed greater facilitation in the left hemisphere than in the right hemisphere. Interestingly the level of difficulty did not mediate how the hemispheres process inferences. The current findings suggest that the consistency of information, rather than the difficulty of a task, primarily influences inference generation in the cerebral hemispheres.

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.

Automatic semantic association between emotional valence and brightness in the right hemisphere

Positive words (e.g., faith) were recognised better when presented in white fonts than in black fonts, whereas the opposite was true for negative words (e.g., enemy). A neural basis for this type of association between emotional valence and brightness was investigated using a visual half-field paradigm. Positive and negative words were presented in black or white fonts and presented to the left visual field–right hemisphere (LVF–RH) or right visual field–left hemisphere (RVF–LH) in a word valence judgement task (i.e., positive vs. negative). A cross-over interaction between emotional valence and brightness was observed; valence judgements were facilitated when a positive word appeared in white and when a negative word appeared in black. This interaction was qualified by a higher-order interaction. The cross-over interaction appeared only for LVF–RH trials, suggesting that the right hemisphere was responsible for the association between emotional valence and brightness.

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.

Hemispheric differences for enhancement and suppression mechanisms during story comprehension

Although readers are able to follow the goals of a character in a story, little is currently known about the underlying enhancement and suppression mechanisms that occur in each cerebral hemisphere. In this study, participants read texts that mentioned a goal of a character, which was later followed by information related to the original goal, a new goal, or unrelated information. Participants then performed a lexical decision task to original-goal-related targets, which were presented to either the left visual field–right hemisphere or the right visual field–left hemisphere. When the original goal was repeated, facilitation was greater in the right hemisphere than the left hemisphere. When a new goal was introduced, the left hemisphere exhibited decreased facilitation for the original goal information. The current findings suggest that two separable mechanisms (i.e., enhancement and suppression), located in different hemispheres, may be involved when readers process goals during narrative text comprehension.

Reduced language processing asymmetry in non-autistic individuals with high levels of autism traits

In the normal population the left hemisphere's predominance for language processing is well established. However, in disorders such as autism atypical patterns of hemispheric lateralisation are common. Given increasing recognition of the idea that autism represents a continuum, we investigated whether the reduced/absent hemispheric asymmetry for language processing extended into the normal population at the upper end of the autism spectrum. A total of 51 participants completed the AQ questionnaire (Baron-Cohen et al., 2001), and a lateralised lexical decision task assessing identification of concrete and abstract words. Based on the clinical finding of decreased hemispheric asymmetry in people with autism, we anticipated reduced hemispheric lateralisation in non-autistic people with higher levels of autism traits. Consistent with prediction, whereas people with lower AQ scores showed a clear right visual field (left hemisphere) advantage for word/nonword discrimination, people with higher AQ scores showed equivalent performance for the left and right visual fields. Our data indicate reduced left hemisphere language dominance in people with higher levels of autism traits, just as people with a clinical diagnosis of autism show atypical lateralisation. Moreover, the data offer further support for the notion that autism is a continuum, rather than a categorical diagnosis, with atypical patterns of hemispheric asymmetry being characteristic of people at the upper end of the spectrum.

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.

Hemispheric asymmetries for temporal information processing: Transient detection versus sustained monitoring

This study investigated functional differences in the processing of visual temporal information between the left and right hemispheres (LH and RH). Participants indicated whether or not a checkerboard pattern contained a temporal gap lasting between 10 and 40 ms. When the stimulus contained a temporal signal (i.e. a gap), responses were more accurate for the right visual field-left hemisphere (RVF-LH) than for the left visual field-right hemisphere (LVF-RH). This RVF-LH advantage was larger for the shorter gap durations (Experiments 1 and 2), suggesting that the LH has finer temporal resolution than the RH, and is efficient for transient detection. In contrast, for noise trials (i.e. trial without temporal signals), there was a LVF-RH advantage. This LVF-RH advantage was observed when the entire stimulus duration was long (240 ms, Experiment 1), but was eliminated when the duration was short (120 ms, Experiment 2). In Experiment 3, where the gap was placed toward the end of the stimulus presentation, a LVF-RH advantage was found for noise trials whereas the RVF-LH advantage was eliminated for signal trials. It is likely that participants needed to monitor the stimulus for a longer period of time when the gap was absent (i.e. noise trials) or was placed toward the end of the presentation. The RH may therefore be more efficient in the sustained monitoring of visual temporal information whereas the LH is more efficient for transient detection.

Flexible contrast gain control in the right hemisphere

This study investigates whether the right hemisphere has more flexible contrast gain control settings for the identification of spatial frequency. Right-handed participants identified 1 and 9 cycles per degree sinusoidal gratings presented either to the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH). When luminance contrast was randomized across a wide range (20–60%), performance gradually improved with contrast in the LVF-RH. Conversely, performance in the RVF-LH was disrupted and saturated for 20 and 60% of contrast, respectively, leading to a LVF-RH advantage for these contrast levels. When contrast was blocked or randomized for a smaller range (30–50%), the LVF-RH advantage was diminished. Flexible contrast gain control is needed when contrast is randomized across a wide range, but not when it is blocked or randomized across a smaller range. The results therefore suggest that the right hemisphere is able to process spatial frequency information across a wider range of contrast levels than is the left hemisphere.

Hemispheric asymmetry in temporal resolution: Contribution of the magnocellular pathway

Right-handed participants performed simple visual judgments on nonverbal stimuli presented either to the left visual field-right hemisphere (LVF-RH) or to the right visual field-left hemisphere (RVF-LH). The stimuli were exposed for 40-120 msec, followed by a backward mask. When the stimuli were presented against a green background, an RVF-LH advantage was observed for the shortest exposure duration. This result supports the notion that the LH has finer temporal resolution than the RH. Imposition of a red background disrupted performance and eliminated the RVF-LH advantage for the shortest exposure duration. Because the red background attenuates functions of the magnocellular pathway, these results suggest that the magnocellular pathway contributes to the LH advantage for fine temporal resolution.

Hemispheric processing of anaphoric inferences: The activation of multiple antecedents

This research investigates the hemispheric processing of anaphors when readers activate multiple antecedents. Participants read texts promoting an anaphoric inference and performed a lexical decision task to inference-related target words that were consistent (Experiment 1) or inconsistent (Experiment 2) with the text. These targets were preceded by constrained or less constraining text and were presented to participants’ right visual field-left hemisphere or to their left visual field-right hemisphere. In Experiment 1, both hemispheres showed facilitation for consistent antecedents and the right hemisphere showed an advantage over the left hemisphere in processing antecedents when preceded by less constrained text. In Experiment 2, the left hemisphere only showed negative facilitation for inconsistent antecedents. When readers comprehend text with multiple antecedents: both hemispheres process consistent information, the left hemisphere inhibits inconsistent information, and the right hemisphere processes less constrained information.

The Role of High Spatial Frequencies in Hemispheric Processing of Categorical and Coordinate Spatial Relations

Right-handed participants performed categorical and coordinate spatial relation tasks on stimuli presented either to the left visual field-right hemisphere (LVF-RH) or to the right visual field-left hemisphere (RVF-LH). The stimuli were either unfiltered or low-pass filtered (i.e., devoid of high spatial frequency content). Consistent with previous studies, the unfiltered condition produced a significant RVF-LH advantage for the categorical task and an LVF-RH advantage for the coordinate task. Low-pass filtering eliminated this Task x Visual Field interaction; thus, the RVF-LH advantage disappeared for the categorical task. The present results suggest that processing of high spatial frequency contributes to the left hemispheric advantage for categorical spatial processing.

Right and Left Hemisphere Cooperation for Drawing Predictive and Coherence Inferences during Normal Story Comprehension

In three experiments, healthy young participants listened to stories promoting inferences and named inference-related test words presented to the right visual field–Left Hemisphere (rvf-LH) or to the left visual field–Right Hemisphere (lvf-RH). Participants showed priming for predictive inferences only for target words presented to the lvf-RH; in contrast, they showed priming for coherence inferences only for target words presented to the rvf-LH. These results, plus the fact that patients with RH brain damage have difficulty drawing coherence inferences and do not show inference-related priming, suggest that information capable of supporting predictive inferences is more likely to be initially activated in the RH than the LH, but following coherence breaks these concepts (now coherence inferences) are completed in the LH. These results are consistent with the theory that the RH engages in relatively coarse semantic coding, which aids full comprehension of discourse.