Priming nouns and verbs: differential influences of semantic and grammatical cues in the two cerebral hemispheres

The current experiment investigated how sentential form-class expectancies influenced lexical-semantic priming within each hemisphere. Sentences were presented that led readers to expect a noun or a verb and the sentence-final target word was presented to one visual field/hemisphere for a lexical decision response. Noun and verb targets in the semantically related condition were compared to an unrelated prime condition, which also predicted part of speech but did not contain any lexical-semantic associates of the target word. The semantic priming effect was strongly modulated by form-class expectancy for RVF/LH targets, for both nouns and verbs. In the LVF/RH, semantic priming was obtained in all conditions, regardless of whether the form-class expectancy was violated. However, the nouns that were preceded by a noun-predicting sentence showed an extremely high priming value in the LVF/RH, suggesting that the RH may have some sensitivity to grammatical predictions for nouns. Comparisons of LVF/RH priming to calculations derived from the LSA model of language representation, which does not utilize word order, suggested that the RH might derive message-level meaning primarily from lexical-semantic relatedness.     

The lateralized stroop: a meta-analysis and its implications for models of semantic processing

The prevailing theory in the literature concerning the lateralization of Stroop effects involves a speed of processing account (see ). Because the left hemisphere (LH) demonstrates an overall advantage relative to the right hemisphere (RH) on most verbal tasks, interference effects are hypothesized to be greater in the LH than in the RH. Inspection of the data, however, reveals that many studies find no difference in magnitude of Stroop interference between the hemispheres. Given findings within the lateralized semantic priming literature, this is not surprising. A meta-analysis on a subset of lateralized Stroop experiments was conducted to determine whether or not the LH produces significantly more interference than the RH in this paradigm. Based on a number of exclusionary criteria, a total of 19 different studies were included, representing a potential 26 effect size estimates of differential interference. The effect size representing interference using congruent conditions as the baseline (d+=.06) reveals that there is no significant difference between the hemispheres in magnitude of the Stroop interference effect. The LH interference effect was d+=.73, which is significant. Likewise, the RH interference effect, d+=.67, was significant. In summary, while there was no significant difference between the hemispheres, each hemisphere, when examined independently, did exhibit significant within hemisphere interference effects. These findings are presented in light of the lateralized semantic priming literature.     

Right hemisphere sensitivity to novel metaphoric relations: application of the signal detection theory

The present study used the signal detection theory to test the hypothesis that the right hemisphere (RH) is more sensitive than the left hemisphere (LH) to the distant semantic relations in novel metaphoric expressions. In two divided visual field experiments, sensitivity (d') and criterion (beta) were calculated for responses to different types of word pairs. In the first experiment, subjects were presented with unfamiliar two-word novel metaphoric expressions ("signal") and unrelated word-pairs ("noise"). In the second experiment, literal expressions ("signal") and unrelated word pairs ("noise") were presented. In line with the Coarse Semantic Coding Theory [Beeman, M. (1998). Coarse semantic coding and discourse comprehension. In: M. Beeman & C. Chiarello (Eds.). Right hemisphere language comprehension: Perspectives from cognitive neuroscience. Mahwah, NJ: Erlbaum, pp. 255-284.] as well as with the Graded Salience Hypothesis [Giora, R. (2003). On our mind: Salience, context and figurative language. New York: Oxford University Press.], the findings suggest that the RH is more sensitive than the LH to unfamiliar metaphoric relations. Furthermore, this RH advantage in processing distant semantic relations did not extend to familiar semantic relations.     

Cognitive consequences of individual differences in arousal asymmetry

Prior research has demonstrated that semantic organization in the right hemisphere (RH) is more diffuse and specialized for distant semantic associates than is semantic organization in the left hemisphere (LH). The present research explored individual differences in this regard. If the RH is more specialized for distant semantic associates, then individuals with a more active RH should display greater activation of distant semantic associations. Two experiments were conducted to examine this issue. In both studies a line bisection task was used to assess arousal asymmetry. In Experiment 1, greater RH activation was associated with the ability to generate remote associates to three word stimuli. In Experiment 2, relatively greater RH activation was associated with enhanced priming of distant semantic associates. Taken together, these experiments demonstrate that arousal asymmetry is an individual difference variable that is related to variability in semantic organization and retrieval.     

Semantic and associative priming in the cerebral hemispheres: some words do, some words don't ... sometimes, some places

This study investigated spreading activation for words presented to the left and right hemispheres using an automatic semantic priming paradigm. Three types of semantic relations were used: similar-only (Deer-Pony), associated-only (Bee-Honey), and similar + associated (Doctor-Nurse). Priming of lexical decisions was symmetrical over visual fields for all semantic relations when prime words were centrally presented. However, when primes and targets were lateralized to the same visual field, similar-only priming was greater in the LVF than in the RVF, no priming was obtained for associated-only words, and priming was equivalent over visual fields for similar + associated words. Similar results were found using a naming task. These findings suggest that it is important to lateralize both prime and target information to assess hemisphere-specific spreading activation processes. Further, while spreading activation occurs in either hemisphere for the most highly related words (those related by category membership and association), our findings suggest that automatic access to semantic category relatedness occurs primarily in the right cerebral hemisphere. These results imply a unique role for the right hemisphere in the processing of word meanings. We relate our results to our previous proposal (Burgess & Simpson, 1988a; Chiarello, 1988c) that there is rapid selection of one meaning and suppression of other candidates in the left hemisphere, while activation spreads more diffusely in the right hemisphere. We also outline a new proposal that activation spreads in a different manner for associated words than for words related by semantic similarity.     

The Experience of Insight Facilitates Long-Term Semantic Priming in the Right Hemisphere

While past research has demonstrated a link between the subjective “Aha” experience of insight and verbal insight problem solution activation in the right hemisphere (RH), no one has yet linked insight to long term semantic priming. We propose that through a shared process of semantic integration both of these concepts are linked and thus the experience of insight should facilitate semantic priming in the RH. Participants attempted to solve a group of compound remote associate problems and afterwards completed a lexical decision task. The results showed that the experience of insight facilitated semantic priming in the RH, but only for unsolved compound remote associate problems. It was also shown that participants who indicated that they generated more solutions through insight that were incorrect demonstrated the most semantic priming in the RH. These results indicate that long-term semantic priming can occur as a result of insight solutions, and that this activation occurs predominantly in the RH. This study extends both the evidence for long-lasting semantic priming as well the theory of coarse semantic coding in the RH.     

Aha! Insight experience correlates with solution activation in the right hemisphere

In one experiment, we tested for an association between semantic activation in the right hemisphere (RH) and left hemisphere (LH) and the Aha! experience when people recognize solutions to insight-like problems. The compound remote associate problems used in this experiment sometimes evoke an Aha! experience and sometimes do not. On each trial, participants (N = 44) attempted to solve these problems and, after 7 sec, named a target word, made a solution decision, and rated their insight experience of recognizing the solution. As in prior studies, the participants demonstrated more solution priming for solutions presented to the left visual field-RH (lvf-RH) than for solutions presented to the right visual field-LH (rvf-LH). As was predicted, following unsolved problems the participants showed greater priming for solutions that they rated as evoking an insight experience on the subsequent solution decision than for solutions that did not evoke an insight experience. This association was stronger for solutions presented to the lvf-RH than for those presented to the rvf-LH. These results tie the subjective experience of insight to an objective measure-semantic priming-and suggest that people have an Aha! experience in part because they already had semantic activation that could lead them to recognize the solution quickly. We believe semantic activation in both hemispheres cooperatively contributes to problem solving, but weak solution activation that contributes to the Aha! experience is more likely to occur in the RH than in the LH.     

Hemispheric Differences in Context Sensitivity During Lexical Ambiguity Resolution

Three experiments were conducted to investigate the influence of contextual constraint on lexical ambiguity resolution in the cerebral hemispheres. A cross-modal priming variant of the divided visual field task was utilized in which subjects heard sentences containing homonyms and made lexical decisions to targets semantically related to dominant and subordinate meanings. Experiment 1 showed priming in both hemispheres of dominant meanings for homonyms embedded in neutral sentence contexts. Experiment 2 showed priming in both hemispheres of dominant and subordinate meanings for homonyms embedded in sentence contexts that biased a central semantic feature of the subordinate meaning. Experiment 3 showed priming of dominant meanings in the left hemisphere (LH), and priming of the subordinate meaning in the right hemisphere (RH) for homonyms embedded in sentences that biased a peripheral semantic feature of the subordinate meaning. These results are consistent with a context-sensitive model of language processing that incorporates differential sensitivity to semantic relationships in the cerebral hemispheres.     

Viewpoint-invariant and viewpoint-dependent object recognition in dissociable neural subsystems

Participants viewed objects in the central visual field and then named either same or different depth-orientation views of these objects presented briefly in the left or the right visual field. The different-orientation views contained either the same or a different set of parts and relations. Viewpoint-dependent priming was observed when test views were presented directly to the right hemisphere (RH), but not when test views were presented directly to the left hemisphere (LH). Moreover, this pattern of results did not depend on whether the same or a different set of parts and relations could be recovered from the different-orientation views. Results support the theory that a specific subsystem operates more effectively than an abstract subsystem in the RH and stores objects in a manner that produces viewpoint-dependent effects, whereas an abstract subsystem operates more effectively than a specific subsystem in the LH and does not store objects in a viewpoint-dependent manner.     

Age effects in a computational model of memory

Previous research demonstrates that semantic priming is relatively unaffected by age (Chiarello, Church, & Hoyer, 1985; Howard, 1988). To determine how age might affect representations in the HAL model of memory, the authors gathered text from older and younger adults and generated a global co-occurrence matrix for each. An analysis demonstrated that, as in humans, there was little difference in measures of semantic priming between memory matrices constructed from the two corpora. However, the authors discovered that semantic word neighborhoods generated by the older adult corpus were denser than corresponding neighborhoods derived from the younger adult corpus. This result has implications for changes in the semantic representation of words due to the aging process.     

Understanding metaphoric sentences in the two cerebral hemispheres

Previous studies indicate that the right hemisphere (RH) has a unique role in maintaining activation of metaphoric single word meanings. The present study investigated hemispheric asymmetries in comprehending metaphoric word meanings within a sentence context. Participants were presented with incomplete priming sentences followed by (literally) true, false, or metaphoric lateralized target words and were asked to decide whether each sentence is literally true or false. Results showed that responses to metaphoric sentences were slower and less accurate than to false sentences when target words were presented to the right visual field (RVF)-LH as well as to the left visual field (LVF)-RH. This suggests that the understanding of lexical metaphors within a sentence context involves LH as well as RH processing mechanisms and that the role of each hemisphere in processing nonliteral language is flexible and may depend on the linguistic task at hand.     

汉语名词、动词和动名兼类词语义加工的偏侧化现象——来自ERP的研究

将ERP技术和半视野技术相结合,采用词汇判断任务,对汉语名词、动词和动名兼类词在左脑和右脑中的加工机制进行了考察。实验结果显示,名词和动词的N400仅在左视野/右脑存在差异,名词和动词的N400在左视野/右脑和右视野/左脑中都比偏（动）和偏（名）更负。不同词类的LPC在右视野/左脑中没有显著差异;偏（名）和偏（动）的LPC在左视野/右脑中比名词和动词更正。实验结果表明,在没有语境条件下,汉语名词和动词的差异主要在具体性上,动名兼类词体现出不同于名词、动词的加工机制。     

A constraint on eliminating semantic priming by repeating a prime

Repeated semantic primes have been shown to generate an additive semantic priming effect when those primes are different words, but repetition priming of the prime seems to eliminate semantic priming of lexical decisions for reasons that are not clear. These studies replicated this effect but also showed that repetition priming of the prime does not eliminate semantic priming with a longer lag between the repeated primes. The implications of these results for understanding the basic effect are discussed.     

词汇加工初期语义属性的激活程度:来自ERP的证据

运用事件相关脑电位（ERP）技术,采用快速掩蔽启动范式和Go/Nogo范式,探讨汉语重复启动和语义相关启动中语义激活程度的差异和特点。实验中要求被试执行一个额外的语义判断任务,对关键刺激不做明显的行为反应。结果发现,在重复启动条件下获得了稳定的N400效应,语义相关启动条件下没有N400效应;重复启动和语义相关启动条件均未产生N250效应。在较短的SOA条件下,词频对语义的激活和加工不产生影响。     

Hemispheric asymmetries in meaning selection: Evidence from the disambiguation of homophonic vs. heterophonic homographs

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

Lateralized repetition priming for familiar faces: Evidence for asymmetric interhemispheric cooperation

Repetition priming refers to facilitated recognition of stimuli that have been seen previously. Although a great deal of work has examined the properties of repetition priming for familiar faces, little has examined the neuroanatomical basis of the effect. Two experiments are presented in this paper that combine the repetition priming paradigm with a divided visual field methodology to examine lateralized recognition of familiar faces. In the first experiment participants were presented with prime faces unilaterally to each visual field and target faces foveally. A significant priming effect was found for prime faces presented to the right hemisphere, but not for prime faces presented to the left hemisphere. In Experiment 2, prime and target faces were presented unilaterally, either to the same visual field or to the opposite visual field (i.e., either within hemisphere or across hemispheres). A significant priming effect was found for the within right hemisphere condition, but not for the within left hemisphere condition, replicating the findings of the first experiment. Priming was also found in both of the across hemispheres conditions, suggesting that interhemispheric cooperation occurs to aid recognition. Taken in combination these experiments provide two main findings. First, an asymmetric repetition priming effect was found, possibly as a result of asymmetric levels of activation following recognition of a prime face, with greater priming occurring within the right hemisphere. Second, there is evidence for asymmetric interhemispheric cooperation with transfer of information from the right hemisphere to the left hemisphere to facilitate recognition.     

Lateralized repetition priming for familiar faces: Evidence for asymmetric interhemispheric cooperation

Repetition priming refers to facilitated recognition of stimuli that have been seen previously. Although a great deal of work has examined the properties of repetition priming for familiar faces, little has examined the neuroanatomical basis of the effect. Two experiments are presented in this paper that combine the repetition priming paradigm with a divided visual field methodology to examine lateralized recognition of familiar faces. In the first experiment participants were presented with prime faces unilaterally to each visual field and target faces foveally. A significant priming effect was found for prime faces presented to the right hemisphere, but not for prime faces presented to the left hemisphere. In Experiment 2, prime and target faces were presented unilaterally, either to the same visual field or to the opposite visual field (i.e., either within hemisphere or across hemispheres). A significant priming effect was found for the within right hemisphere condition, but not for the within left hemisphere condition, replicating the findings of the first experiment. Priming was also found in both of the across hemispheres conditions, suggesting that interhemispheric cooperation occurs to aid recognition. Taken in combination these experiments provide two main findings. First, an asymmetric repetition priming effect was found, possibly as a result of asymmetric levels of activation following recognition of a prime face, with greater priming occurring within the right hemisphere. Second, there is evidence for asymmetric interhemispheric cooperation with transfer of information from the right hemisphere to the left hemisphere to facilitate recognition.     

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.     

Anomaly detection in the right hemisphere: The influence of visuospatial factors

Previous research with both brain-damaged and neurologically intact populations has demonstrated that the right cerebral hemisphere (RH) is superior to the left cerebral hemisphere (LH) at detecting anomalies (or incongruities) in objects (Ramachandran, 1995; Smith, Tays, Dixon, & Bulman-Fleming, 2002). The current research assesses whether the RH advantage for anomaly detection is due to the RH superiority for visuospatial skills or is a distinct cognitive process. Sixty undergraduate participants completed tasks assessing anomaly detection, mental rotation, and global and local perceptual abilities. The results demonstrate that anomaly detection is negatively correlated with mental rotation. These findings suggest that anomaly detection is not simply a function of visuospatial skills.     

Hemispheric asymmetries in meaning selection: Evidence from the disambiguation of homophonic vs. heterophonic homographs

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