The neural substrates of action retrieval: An examination of semantic and visual routes to action

We report three PET experiments that examine the neural substrates of the conceptual components of action retrieval. In all three experiments, subjects made action or screen-size decisions to familiar objects presented either as pictures or written words (the names ofthe objects). In Experiment 1, a third task was included, requiring a decision on the real-life size of the stimuli. In Experiment 2, a third stimulus type was included, with action and size decisions also performed on pictures of meaningless novel objects. Finally, in Experiment 3, we changed the response mode from a button press to a more explicit movement made with a “manipulandum”. Based on neuropsychological findings, we predicted that when action responses were made to pictures of familiar or novel objects, relative to words, there would be less activation in semantic regions but greater activation in visual, motor, and perhaps parietal cortices. We found that, action relative to screen-size decisions on both pictures and words activated the left hemisphere temporo-frontal semantic system with activation in the left posterior middle temporal cortex specific to action retrieval (Experiment 1). In addition, action retrieval elicited more activation for (1) words than pictures in areas associated with semantics; and (2) novel objects than words or familiar objects in areas associated with pre-semantic object processing. These results are discussed in the context of semantic and visual routes to action retrieval.     

空间隐喻和形状变化对物体内隐时间概念加工的影响

通过2个实验, 考察了空间隐喻和形状变化对物体内隐时间概念加工的影响。实验1通过对隐含时间关系的词对的语义相关判断发现, 形状变化物体隐含的“先前/后来”的时间概念与“左/右”的空间概念存在着对应关系, 断裂式变化(形状变化大)的物体比渐进式变化(形状变化小)的物体激发了更加明显的时间变化感, 但物体形状变化类型并未明显地影响对词对语义相关判断的速度和准确性。实验2通过对隐含时间关系的物体图片对的语义相关判断发现, 物体形状变化隐含的“先前/后来”的时间概念与“左/右”的空间概念亦存在着对应关系, 而且物体形状变化类型影响对物体图片对语义相关判断的速度和准确性, 被试对渐进式变化物体的语义相关判断显著快于对断裂式变化物体的语义相关判断, 错误率亦低。整个研究表明, 在物体形状变化内隐时间概念的表征中, 既存在着抽象的符号表征, 又存在着具体的形状知觉表征。研究结果支持概念双加工理论的预言。     

纳西象形文字识别中的形、音、义激活

对纳西象形文字识别中的形、音、义激活进行了考察。实验1采用色词干扰的实验范式。结果表明,纳西象形文字的字形比字音和语义更易被激活。命名颜色字的形似字的颜色比命名颜色字的音同或音似字、语义联想字的颜色快。实验2采用色词干扰实验范式的变式。结果表明,当SOA=100ms时,颜色字及其形似字对颜色块命名的启动效应显著。当SOA为200ms和400ms时,颜色字的语义联想字对颜色块命名的启动效应显著。整个研究表明,在纳西象形文字识别中,字形信息首先被激活,其次是语义,字音的激活不明显。纳西象形文字的识别符合直通假设。所以如此,与纳西象形文字的特点有关     

The priming effect of translation equivalents across languages for concrete and abstract words

The present study used a masked priming paradigm and two language tasks (lexical decision, semantic categorical judgment) to investigate whether concrete and abstract words share the same degree of conceptual representation across languages for bilinguals. The results showed that the priming effect of translation equivalents did not differ for concrete and abstract words in the lexical decision task, in both prime-target directions (in Experiment 1). The same results were also found in the semantic categorical judgment task in either prime-target direction (in Experiment 2). Our results do not provide support for the representation difference hypothesis of concrete and abstract words of Distributed Representation Model (De Groot, 1992a, 1992b; Van Hell & De Groot, 1998), which assumes that concrete words share more semantic components in the conceptual representations across languages, compared with abstract words. Rather, our findings suggest that both concrete and abstract words have the same degree of overlap in conceptual representations across a bilingual's two languages.     

Analogical priming via semantic relations

Research on semantic memory has often tacitly treated semantic relations as simple conduits for spreading activation between associated object concepts, rather than as integral components of semantic organization. Yet conceptual relations, and the role bindings they impose on the objects they relate, are central to such cognitive tasks as discourse comprehension, inference, problem solving, and analogical reasoning. The present study addresses the question of whether semantic relations and their bindings can influence access to semantic memory. The experiments investigated whether, and under what conditions, presenting a prime pair of words linked by 1 of 10 common semantic relations would facilitate processing of a target pair of words linked by the same relation. No effect was observed when participants merely read the prime; however, relational priming was observed under instructions to note and use the semantic relations. Participants were faster at making a lexical decision or naming a word on a related pair of target words when that pair was primed with an analogously related pair of words than when the prime pair consisted of either two unrelated words or two words linked by some other relation. This evidence of analogical priming suggests that under an appropriate strategic set, lexical decisions and naming latencies can be influenced by a process akin to analogical mapping.     

The different representational frameworks underpinning abstract and concrete knowledge: Evidence from odd-one-out judgements

Recent evidence from neuropsychological investigations of individuals with global aphasia and deep or deep-phonological dyslexia suggests that abstract and concrete concepts are underpinned by qualitatively different representational frameworks. Abstract words are represented primarily by their association to other words, whilst concrete words are represented primarily by their taxonomic similarity to one another. In the current study, we present the first evidence for this association/similarity distinction to be gathered from healthy research participants. Using a semantic odd-one-out task, it is shown that normal participants identify associative connections more quickly than similarity-based connections when processing abstract words, but that the pattern is reversed for concrete words. It is also demonstrated that the typical concrete-word advantage observed in many cognitive tasks is abolished and even reversed when participants have to comprehend the semantic associations between words. The data provide converging evidence for the different representational frameworks hypothesis and suggest that claims based on information from previous neuropsychological investigations can be generalized to normal cognition.     

无语境条件下汉语词类歧义词的意义激活

以单字词为实验材料,采用启动命名任务,在孤立词条件下考察了汉语词类歧义词不同意义激活的时间进程特点。实验发现,歧义词的两种意义都能被激活,但主要意义激活得较早,次要意义激活速度较慢;当两种意义都激活之后,次要意义的激活水平降低,而主要意义仍维持在一定激活水平。结果表明,汉语词类歧义词的多重激活过程会受到意义相对频率的影响。     

Episodic encoding and recognition of pictures and words: role of the human medial temporal lobes

In the present PET study, we examined brain activity related to processing of pictures and printed words in episodic memory. Our goal was to determine how the perceptual format of objects (verbal versus pictorial) is reflected in the neural organization of episodic memory for common objects. We investigated this issue in relation to encoding and recognition with a particular focus on medial temporal-lobe (MTL) structures. At encoding, participants saw pictures of objects or their written names and were asked to make semantic judgments. At recognition, participants made yes-no recognition judgments in four different conditions. In two conditions, target items were pictures of objects; these objects had originally been encoded either in picture or in word format. In two other conditions, target items were words; they also denoted objects originally encoded either as pictures or as words. Our data show that right MTL structures are differentially involved in picture processing during encoding and recognition. A posterior MTL region showed higher activation in response to the presentation of pictures than of words across all conditions. During encoding, this region may be involved in setting up a representation of the perceptual information that comprises the picture. At recognition, it may play a role in guiding retrieval processes based on the perceptual input, i.e. the retrieval cue. Another more anterior right MTL region was found to be differentially involved in recognition of objects that had been encoded as pictures, irrespective of whether the retrieval cue provided was pictorial or verbal in nature; this region may be involved in accessing stored pictorial representations. Our results suggest that left MTL structures contribute to picture processing only during encoding. Some regions in the left MTL showed an involvement in semantic encoding that was picture specific; others showed a task-specific involvement across pictures and words. Together, our results provide evidence that the involvement of some but not all MTL regions in episodic encoding and recognition is format specific.     

The effects of phonological similarity on the semantic categorisation of pictorial and lexical stimuli: evidence from continuous behavioural measures

Behavioural and neuroimaging studies provide evidence of automatic activation of phonology (e.g., covert speech) during the recognition of lexical stimuli. Implicit processing of phonological information was investigated in a kinematic study of semantic categorisation of pictures (session A) or words (session B). Participants clicked one of two items (target and distractor) based on their semantic congruency (artefact or natural) with a cued-word. Phonological similarity between cued-word and distractor was varied. The presence of the phonological distractor produced trajectories with greater curvature towards the competing semantic category than did the presence of a distractor not phonologically related. This suggests that the semantic categorisation of pictorial and lexical stimuli is influenced by the automatic activation of phonological information. Trajectories’ curvature reveals competition between partially activated phonological and semantic representations suggesting that phonological codes involved in linguistic processing influence the dynamic competition underlying the semantic categorisation of lexical and pictorial.     

Semantic activation during object naming

Summary The study deals with the processes of semantic activation which accompany the response of naming an object. A general model of semantic activation is presented, characterized by the proposal of the existence of different components of the semantic representations that constitute the conceptual nodes corresponding to objects. Within these, a distinction is made between elements corresponding to physical properties of the stimulus objects, and more abstract, functional elements. Two distinct routes are proposed for the activation of the concept node, a direct and an indirect one. A further distinction made in the present study is between categories characterized predominantly in terms of perceptual properties, and primarily conceptual categories.The study reports two sets of experiments, the first one offering support to the distinction of two activation routes, the second to the notion of the existence of two types of categories. This latter distinction also allows a convincing explanation for various facts reported in the literature, in particular for the difference in categorization and in naming latencies for objects and for words.     

语义表征具身理论:情绪在概念表征中的作用

概念如何被表征是认知科学的热点问题,其中抽象概念如何表征是当前具身认知最具争议性的话题之一。与前期概念隐喻理论(强调意象图式)和知觉符号理论(强调情境内省信息)的观点不同,语义表征具身理论强调情绪经验信息在抽象概念表征和加工中的作用。具体而言,具体概念的表征主要来自感觉运动信息,而抽象概念的表征主要来自情绪经验信息和语言信息。研究证明,抽象概念的高情绪经验信息能够促进词汇的加工,且这一促进作用受词汇情绪效价的调节。未来研究应进一步考虑影响情绪经验信息发挥作用的因素,比如语言信息的丰富性、情绪唤醒或个体的情绪状态等。     

Large,colorful, or noisy? Attribute- and modality-specific activations during retrieval of perceptual attribute knowledge

Position emission tomography was used to investigate whether retrieval of perceptual knowledge from long-term memory activates unique cortical regions associated with the modality and/or attribute type retrieved. Knowledge about the typical color, size, and sound of common objects and animals was probed, in response to written words naming the objects. Relative to a nonsemantic control task, all the attribute judgments activated similar left temporal and frontal regions. Visual (color, size) knowledge selectively activated the right posterior inferior temporal (PIT) cortex, whereas sound judgments elicited selective activation in the left posterior superior temporal gyrus and the adjacent parietal cortex. All of the attribute judgments activated a left PIT region, but color retrieval generated more activation in this area. Size judgments activated the right medial parietal cortex. These results indicate that the retrieval of perceptual semantic information activates not only a general semantic network, but also cortical areas specialized for the modality and attribute type of the knowledge retrieved.     

Semantic priming with abstract and concrete words: differential asymmetry may be postlexical

We investigated whether abstract and concrete words would be differentially effective in priming lexical decisions to words presented to the right and left visual fields. Under low probability prime conditions, where priming is presumed to reflect a spreading activation process within the lexicon, equivalent priming was obtained in each VF for both abstract and concrete primes. However, when the same words were used in a high probability prime paradigm, abstract primes were much less effective in the LVF than in the RVF, while priming with concrete words did not differ across the visual fields. Since such priming may reflect a postlexical semantic integration stage, the results imply that hemisphere differences for processing abstract and concrete words may arise only after lexical access has occurred, when semantic information retrieved from the lexicon becomes available for subsequent processing.     

情绪名词的具体性效应：来自ERP的证据

词汇的具体性和情绪性是影响词汇加工的不同因素, 高具体性和情绪性都能够促进词汇的加工。本研究同时操纵词汇的具体性和情绪性, 使用词汇判定任务和愉悦度判断任务, 探讨了情绪名词的具体性效应及其具体性效应是否受词汇情绪信息的影响。结果发现：情绪名词的具体性效应受内隐或外显情绪条件的影响, 具体的情绪词比抽象的情绪词反应时间更短、正确率更高, 诱发了更大的N400和减小的LPC, 但LPC的具体性效应只表现在内隐情绪任务中。词汇的具体性和情绪性的相互影响发生在内隐情绪任务中的语义加工阶段, 正性、负性的具体词和抽象词的加工在N400成分上差异不显著, 而中性具体词和抽象词在N400成分上差异显著, 说明词汇的情绪信息为抽象词的加工提供了充分的语境, 因此消除了具体词的加工优势。     

Spatial distance effects on incremental semantic interpretation of abstract sentences: Evidence from eye tracking

A large body of evidence has shown that visual context information can rapidly modulate language comprehension for concrete sentences and when it is mediated by a referential or a lexical-semantic link. What has not yet been examined is whether visual context can also modulate comprehension of abstract sentences incrementally when it is neither referenced by, nor lexically associated with, the sentence. Three eye-tracking reading experiments examined the effects of spatial distance between words (Experiment 1) and objects (Experiment 2 and 3) on participants’ reading times for sentences that convey similarity or difference between two abstract nouns (e.g., ‘Peace and war are certainly different...’). Before reading the sentence, participants inspected a visual context with two playing cards that moved either far apart or close together. In Experiment 1, the cards turned and showed the first two nouns of the sentence (e.g., ‘peace’, ‘war’). In Experiments 2 and 3, they turned but remained blank. Participants’ reading times at the adjective (Experiment 1: first-pass reading time; Experiment 2: total times) and at the second noun phrase (Experiment 3: first-pass times) were faster for sentences that expressed similarity when the preceding words/objects were close together (vs. far apart) and for sentences that expressed dissimilarity when the preceding words/objects were far apart (vs. close together). Thus, spatial distance between words or entirely unrelated objects can rapidly and incrementally modulate the semantic interpretation of abstract sentences.     

Neural dichotomy of word concreteness: a view from functional neuroimaging

Our perception about the representation and processing of concrete and abstract concepts is based on the fact that concrete words are highly imagined and remembered faster than abstract words. In order to explain the processing differences between abstract and concrete concepts, various theories have been proposed, yet there is no unanimous consensus about its neural implication. The present study investigated the processing of concrete and abstract words during an orthography judgment task (implicit semantic processing) using functional magnetic resonance imaging to validate the involvement of the neural regions. Relative to non-words, both abstract and concrete words show activation in the regions of bilateral hemisphere previously associated with semantic processing. The common areas (conjunction analyses) observed for abstract and concrete words are bilateral inferior frontal gyrus (BA 44/45), left superior parietal (BA 7), left fusiform gyrus and bilateral middle occipital. The additional areas for abstract words were noticed in bilateral superior temporal and bilateral middle temporal region, whereas no distinct region was noticed for concrete words. This suggests that words with abstract concepts recruit additional language regions in the brain.     

The meaning of ‘life’ and other abstract words: Insights from neuropsychology

There are a number of long‐standing theories on how the cognitive processing of abstract words, like ‘life’, differs from that of concrete words, like ‘knife’. This review considers current perspectives on this debate, focusing particularly on insights obtained from patients with language disorders and integrating these with evidence from functional neuroimaging studies. The evidence supports three distinct and mutually compatible hypotheses. (1) Concrete and abstract words differ in their representational substrates, with concrete words depending particularly on sensory experiences and abstract words on linguistic, emotional, and magnitude‐based information. Differential dependence on visual versus verbal experience is supported by the evidence for graded specialization in the anterior temporal lobes for concrete versus abstract words. In addition, concrete words have richer representations, in line with better processing of these words in most aphasic patients and, in particular, patients with semantic dementia. (2) Abstract words place greater demands on executive regulation processes because they have variable meanings that change with context. This theory explains abstract word impairments in patients with semantic‐executive deficits and is supported by neuroimaging studies showing greater response to abstract words in inferior prefrontal cortex. (3) The relationships between concrete words are governed primarily by conceptual similarity, while those of abstract words depend on association to a greater degree. This theory, based primarily on interference and priming effects in aphasic patients, is the most recent to emerge and the least well understood. I present analyses indicating that patterns of lexical co‐occurrence may be important in understanding these effects.     

Qualitative differences in the representation of abstract versus concrete words: Evidence from the visual-world paradigm

In the present visual-world experiment, participants were presented with visual displays that included a target item that was a semantic associate of an abstract or a concrete word. This manipulation allowed us to test a basic prediction derived from the qualitatively different representational framework that supports the view of different organizational principles for concrete and abstract words in semantic memory. Our results confirm the assumption of a primary organizational principle based on association for abstract words, different from the semantic similarity principle proposed for concrete words, and provide the first piece of evidence in support of this view obtained from healthy participants. The results shed light on the representational structure of abstract and concrete concepts.     

Attention can operate on semantic objects defined by individual Chinese characters

Attention can select perceptual objects, but it is less clear whether attention can operate on objects defined by higher level cognition, such as semantic associations. Recent studies have shown that attention may be based on objects defined by Chinese two-character compound words, suggesting that attention can operate on semantic objects. In the present study, object-based attention (OBA) effect was investigated at the level of individual Chinese characters, and the role of character structure and radical order in OBA was explored by using a spatial cueing paradigm. In Experiment 1, we found OBA effect for conditions that had legal radical order, but not for other conditions in which the radical order information was disrupted. Character structure, however, had no influence on the OBA effect. In Experiment 2, we observed OBA effect for all conditions after enhancing the radical order and character structure information by adding perceptual cues. The results extend previous findings of a “semantic object”-based attention effect from the two-character word level to the individual character level. Moreover, we found that radical order but not character structure was important for this semantic OBA effect. We conclude that visual attention can be based on semantic objects at the level of individual characters, and that the development of semantic objects is affected by the perceptual grouping of the radicals.     

句子背景下缺失音素的中文听觉词理解的音、义激活进程（Ⅱ）

采用缺失音素的中文双字词为材料,进一步考察了中文听觉词的语音、语义激活进程。共包含两个实验：实验1考察听觉词语音能否同时激活多个与之语音相近的语音、语义结点;实验2考察在听觉词词汇提取后期,是否还存在语音的激活作用。结果表明：⑴中文听觉词的语音能够同时激活与之语音相近的语音、语义结点,这种语音作用在ISI=400ms时处于较低水平;⑵听觉词呈现结束后,语音存在着二次激活现象;⑶对缺失声母的中文听觉词理解后期,除语义背景依赖效应外,还存在明显的语音作用,两者共同作用共同实现对目标词的语义恢复。根据对句子背景下缺失声母的中文听觉词理解的实验结果,作者提出了“中文听觉词理解的激活扩散动态模型”。