Cumulative and non-cumulative semantic interference in object naming: Evidence from blocked and continuous manipulations of semantic context

Experiments involving blocked and continuous manipulations of the semantic naming context demonstrate that, when speakers name several taxonomically related objects in close succession, they display persistent interference effects. A review of studies using the blocked paradigm shows that, unlike the continuous paradigm, it typically does not induce cumulative interference effects in healthy speakers. This contrasts with the simulation results obtained from a model of semantic context effects recently put forward by Oppenheim and colleagues [Oppenheim, G. M., Dell, G. S., & Schwartz, M. F. (2010). The dark side of incremental learning: A model of cumulative semantic interference during lexical access in speech production. Cognition, 114, 227--262], which generates cumulative effects in both paradigms. We propose that the effects are non-cumulative in the blocked paradigm, because it allows participants to bias top-down the levels of activation of lexical-semantic representations, thereby curtailing the accumulating interference. Indeed, prior research has shown that the interference effects in the blocked paradigm are exacerbated when participants carry out a concurrent digit-retention task, loading on working memory and reducing their capacity to exert a top-down bias. In Experiment 1, combining the continuous paradigm with a digit-retention task, we demonstrate that this does not exacerbate cumulative context effects, corroborating the selective role of working memory and the associated top-down biasing mechanism in the blocked paradigm. A review of neuropsychological and neuroimaging studies demonstrates that left inferior frontal regions may play a critical role in controlling semantic interference top-down. We discuss the implications of these findings for language production research and for models of lexical-semantic encoding.     

Age of acquisition effects in picture naming: evidence for a lexical-semantic competition hypothesis

In many tasks the effects of frequency and age of acquisition (AoA) on reaction latencies are similar in size. However, in picture naming the AoA-effect is often significantly larger than expected on the basis of the frequency-effect. Previous explanations of this frequency-independent AoA-effect have attributed it to the organisation of the semantic system or to the way phonological word forms are stored in the mental lexicon. Using a semantic blocking paradigm, we show that semantic context effects on naming latencies are more pronounced for late-acquired than for early-acquired words. This interaction between AoA and naming context is likely to arise during lexical-semantic encoding, which we put forward as the locus for the frequency-independent AoA-effect.     

图画口语命名中的语义效应

图画口语命名包括了概念准备、词条选择、音韵编码和发音等加工阶段, 是口语产生研究中经典的实验任务。文章首先简要介绍了两类言语产生的基础理论, 然后介绍了不同研究范式下的语义抑制效应与语义促进效应。在此基础上总结了影响语义效应的各种因素, 并重点介绍了竞争说、动态词汇网络假说、反应一致说、语义选择说以及反应排除说。最后基于已有的研究成果与研究现状指出了下一步的研究方向。     

Lexical Retrieval Deficit in Picture Naming: Implications for Word Production Models

In models of word retrieval, it is common to differentiate lexical-semantic (word meaning) and lexical-phonological (word form) levels. There has been considerable interest in the relationship between these two levels. The so-called discrete two-stage model claims that phonological activation follows selection at the lexical-semantic level and is limited only to the selected item. In contrast, nondiscrete (interactive and cascade) models assume that all activated lexical-semantic candidates are also phonologically activated to some extent. We addressed this issue by studying an anomic patient who suffered from a partial functional disconnection between lexical-semantic and lexical-phonological levels. A multitarget repeated naming task with phonological training was employed. Systematic manipulation of semantic and phonological relatedness between the to-be-named items indicated that our patient's word error patterns were sensitive to both types of lexical relatedness. A delayed repetition task employing the same items failed to show similar effects, suggesting that they were specific to naming. The discrete two-stage model is unable to explain the observed effects of semantic and phonological relatedness. However, they are consistent with assumptions of nondiscrete models of lexical retrieval. In addition to the theoretical implications of this study, the observed effects of lexical context on word retrieval have implications for treatment of anomia.     

The role of lexical competition and acoustic-phonetic structure in lexical processing: evidence from normal subjects and aphasic patients

This study examined the effects that the acoustic-phonetic structure of a stimulus exerts on the processes by which lexical candidates compete for activation. An auditory lexical decision paradigm was used to investigate whether shortening the VOT of an initial voiceless stop consonant in a real word results in the activation of the lexical-semantic network of its voiced competitor, i.e., does acoustically modified time prime penny via dime. Results for normal subjects showed semantic priming for related pairs and mediated priming for voiced competitors, consistent with cascade models of language processing allowing for interaction between phonological and semantic levels of processing. Although Broca's aphasics showed semantic priming (dime primed penny), they failed to show priming in the context of a lexical competitor. These results are consistent with the hypothesis that these patients have a lexical processing deficit characterized by an overall reduction in lexical activation.     

Implicit and explicit processing in deep dyslexia: Semantic blocking as a test for failure of inhibition in the phonological output lexicon

The failure of inhibition hypothesis posits a theoretical distinction between implicit and explicit access in deep dyslexia. Specifically, the effects of failure of inhibition are assumed only in conditions that have an explicit selection requirement in the context of production (i.e., aloud reading). In contrast, the failure of inhibition hypothesis proposes that implicit processing and explicit access to semantic information without production demands are intact in deep dyslexia. Evidence for intact implicit and explicit access requires that performance in deep dyslexia parallels that observed in neurologically intact participants on tasks based on implicit and explicit processes. In other words, deep dyslexics should produce normal effects in conditions with implicit task demands (i.e., lexical decision) and on tasks based on explicit access without production (i.e., forced choice semantic decisions) because failure of inhibition does not impact the availability of lexical information, only explicit retrieval in the context of production. This research examined the distinction between implicit and explicit processes in deep dyslexia using semantic blocking in lexical decision and forced choice semantic decisions as a test for the failure of inhibition hypothesis. The results of the semantic blocking paradigm support the distinction between implicit and explicit processing and provide evidence for failure of inhibition as an explanation for semantic errors in deep dyslexia.     

Refractory effects in picture naming as assessed in a semantic blocking paradigm.

In the cyclic semantic blocking paradigm participants repeatedly name sets of objects with semantically related names (homogeneous sets) or unrelated names (heterogeneous sets). The naming latencies are typically longer in related than in unrelated sets. In Experiment 1 we replicated this semantic blocking effect and demonstrated that the effect only arose after all objects of a set had been shown and named once. In Experiment 2, the objects of a set were presented simultaneously (instead of on successive trials). Evidence for semantic blocking was found in the naming latencies and in the gaze durations for the objects, which were longer in homogeneous than in heterogeneous sets. For the gaze-to-speech lag between the offset of gaze on an object and the onset of the articulation of its name, a repetition priming effect was obtained but no blocking effect. Experiment 3 showed that the blocking effect for speech onset latencies generalized to new, previously unnamed lexical items. We propose that the blocking effect is due to refractory behaviour in the semantic system.     

Top-down effects of semantic knowledge in visual search are modulated by cognitive but not perceptual load

Moores, Laiti, and Chelazzi (2003) found semantic interference from associate competitors during visual object search, demonstrating the existence of top-down semantic influences on the deployment of attention to objects. We examined whether effects of semantically related competitors (same-category members or associates) interacted with the effects of perceptual or cognitive load. We failed to find any interaction between competitor effects and perceptual load. However, the competitor effects increased significantly when participants were asked to retain one or five digits in memory throughout the search task. Analyses of eye movements and viewing times showed that a cognitive load did not affect the initial allocation of attention but rather the time it took participants to accept or reject an object as the target. We discuss the implications of our findings for theories of conceptual short-term memory and visual attention.     

Social anxiety and attentional biases: A top-down contribution?

Selective attention toward threatening facial expressions has been found to precipitate and maintain symptoms of social anxiety. However, the automaticity of this bias is under debate. In the present study, we aimed to test whether top-down (controlled) engagement and disengagement of attention toward threatening faces is associated with social anxiety. This was examined by testing the impact of a secondary working memory (WM) load on attentional biases. In a variation of the dot-probe task, participants’ attention was initially cued to the left or right of fixation before an upright face paired with an inverted face was presented (displaying a disgust or neutral expression), and participants responded to a subsequently presented probe. The task was performed under no-load, low-load (one-digit memory task), and high-load (six-digit memory task) conditions. Social anxiety was not found to be associated with delayed disengagement from threat. However, surprisingly, high social anxiety was associated with an engagement bias away from threat, whereas low social anxiety was associated with a bias toward threat. These results were unaffected by the WM load manipulation. This indicates that engagement with threatening facial expressions has minimal contributions from top-down mechanisms, since it is likely that orienting to facial expressions occurs relatively automatically.     

The reaction-time task-rule congruency effect is not affected by working memory load: further support for the activated long-term memory hypothesis

Previous studies claimed that task representation is carried out by the activated long-term memory portion of working memory (WM; Meiran and Kessler in J Exp Psychol Human Percept Perform 34:137–157, 2008). The present study provides a more direct support for this hypothesis. We used the reaction-time task-rule congruency effect (RT-TRCE) in a task-switching setup, and tested the effects of loading WM with irrelevant task rules on RT-TRCE. Experiment 1 manipulated WM load in a between-subject design. WM participants performed a color/shape task switching, while having 0, 1 or 3 numerical task rules as WM load. Experiment 2 used a similar load manipulation (1 or 3 rules to load WM) in a within-subject design. Experiment 3 extended these results by loading WM with perceptual tasks that were more similar to the shape/color tasks. The results show that RT-TRCE was not affected by WM load supporting the activated long-term memory hypothesis.     

Evidence that a transient but cognitively demanding process underlies forward blocking

Blocking is a learning phenomenon in which prior experience inhibits learning about novel cues. Though the phenomenon itself has been well documented, the details of blocking-related processes still remain contentious. Two experiments investigated whether participants were engaged in demanding cognitive processing during different portions of a standard blocking paradigm. Participants in Experiment 1 engaged in a simple secondary task while completing a standard blocking procedure. Results showed that performance on the secondary task was briefly diminished early in the second phase of the blocking paradigm, when the novel cue is first paired with the pretrained cue. Participants in Experiment 2 performed a difficult cognitive load task during either the early or the late portions of the second phase of blocking. The blocking effect was eliminated when learners were under load early in the second phase, but not when learners were under load late in the second phase. These results suggest that blocking relies on a cognitively demanding process with a distinct time course. Computational simulations illustrate how a model that includes top-down (i.e., cognitively demanding) attentional modulation can reproduce the observed behaviour. This suggests that purely associative processes are not sufficient to explain the observed behaviour. Implications for current accounts of blocking are discussed.     

Intact attentional control of working memory encoding in schizophrenia

This study reports evidence that individuals with schizophrenia (SC) demonstrate intact attentional selection for visual working memory (WM) storage. A group of 62 participants with SC and 55 control participants without SC were studied in a series of 5 experiments that examined the ability to use top-down and bottom-up cues to guide WM encoding, as well as the ability to spontaneously select a subset of representations for storage. Participants with SC exhibited a consistent and robust ability to use selective attention in the control of WM in all 5 experiments, demonstrating a remarkable island of preserved functioning given the broad spectrum of impairments of attention and WM that have been widely reported in those with SC. These findings indicate that attention is not globally impaired in SC and make it possible to delineate more precisely the nature of the specific impairment of attention in this disorder.     

工作记忆负荷对无意注意的影响

通过探讨工作记忆负荷对无意注意的影响,考察工作记忆的认知控制功能对选择性注意的作用机制。为了避免工作记忆和选择注意的目标或者干扰子之间的知觉注意资源的竞争,采用言语工作记忆任务和视觉空间位置辨别任务,同时视觉干扰刺激采用被试无法识别的韩语。结果发现,在高负荷条件下,干扰效应显著;而在低和中负荷条件下,没有观察到干扰效应。说明在高负荷条件下,被试没有额外的资源来抑制干扰加工,从而出现了显著的干扰效应。由此,本研究支持负荷理论的观点：工作记忆在选择性注意中执行认知控制功能。     

Co-speech iconic gestures and visuo-spatial working memory

Three experiments tested the role of verbal versus visuo-spatial working memory in the comprehension of co-speech iconic gestures. In Experiment 1, participants viewed congruent discourse primes in which the speaker's gestures matched the information conveyed by his speech, and incongruent ones in which the semantic content of the speaker's gestures diverged from that in his speech. Discourse primes were followed by picture probes that participants judged as being either related or unrelated to the preceding clip. Performance on this picture probe classification task was faster and more accurate after congruent than incongruent discourse primes. The effect of discourse congruency on response times was linearly related to measures of visuo-spatial, but not verbal, working memory capacity, as participants with greater visuo-spatial WM capacity benefited more from congruent gestures. In Experiments 2 and 3, participants performed the same picture probe classification task under conditions of high and low loads on concurrent visuo-spatial (Experiment 2) and verbal (Experiment 3) memory tasks. Effects of discourse congruency and verbal WM load were additive, while effects of discourse congruency and visuo-spatial WM load were interactive. Results suggest that congruent co-speech gestures facilitate multi-modal language comprehension, and indicate an important role for visuo-spatial WM in these speech–gesture integration processes.     

Concreteness effects in different tasks: implications for models of short-term memory

This study investigates concreteness effects in tasks requiring short-term retention. Concreteness effects were assessed in serial recall, matching span, order reconstruction, and free recall. Each task was carried out both in a control condition and under articulatory suppression. Our results show no dissociation between tasks that do and do not require spoken output. This argues against the redintegration hypothesis according to which lexical-semantic effects in short-term memory arise only at the point of production. In contrast, concreteness effects were modulated by task demands that stressed retention of item versus order information. Concreteness effects were stronger in free recall than in serial recall. Suppression, which weakens phonological representations, enhanced the concreteness effect with item scoring. In a matching task, positive effects of concreteness occurred with open sets but not with closed sets of words. Finally, concreteness effects reversed when the task asked only for recall of word positions (as in the matching task), when phonological representations were weak (because of suppression), and when lexical semantic representations overactivated (because of closed sets). We interpret these results as consistent with a model where phonological representations are crucial for the retention of order, while lexical-semantic representations support maintenance of item identity in both input and output buffers.     

Concreteness effects in different tasks: Implications for models of short-term memory

This study investigates concreteness effects in tasks requiring short-term retention. Concreteness effects were assessed in serial recall, matching span, order reconstruction, and free recall. Each task was carried out both in a control condition and under articulatory suppression. Our results show no dissociation between tasks that do and do not require spoken output. This argues against the redintegration hypothesis according to which lexical-semantic effects in short-term memory arise only at the point of production. In contrast, concreteness effects were modulated by task demands that stressed retention of item versus order information. Concreteness effects were stronger in free recall than in serial recall. Suppression, which weakens phonological representations, enhanced the concreteness effect with item scoring. In a matching task, positive effects of concreteness occurred with open sets but not with closed sets of words. Finally, concreteness effects reversed when the task asked only for recall of word positions (as in the matching task), when phonological representations were weak (because of suppression), and when lexical semantic representations overactivated (because of closed sets). We interpret these results as consistent with a model where phonological representations are crucial for the retention of order, while lexical-semantic representations support maintenance of item identity in both input and output buffers.     

Attentional processing and the subjective contour illusion

Leading explanations of the subjective contour illusion can be classified as being either "bottom-up" or "top-down." Bottom-up explanations assert that peripheral, physiological mechanisms often associated with the perception of real contours also account for subjective contour (SC) perception. In contrast, top-down explanations posit a more central locus of SC perception and are formulated on a molar, psychological level. A major aspect of bottom-up perceptual processing is that it is largely automatic. On the other hand, top-down processing implies a greater role for selective attention. In an effort to distinguish between bottom-up and top-down accounts of SC perception, the present investigation used a dual-task paradigm to test the relative attentional demands of real contour perception versus SC perception. In the primary task, subjects made speeded same-different discriminations of either paired SC forms or their real contour analogues. Half the subjects performed this primary task in conjunction with a six-digit short-term memory load secondary task. If subjective forms indeed impose a greater limited-capacity processing load than real forms, then the need to share processing capacity with a secondary task was expected to produce a greater increment in reaction time (RT) for subjective relative to real forms. The results indicated that the expected enhanced RT increment for subjective relative to real forms with the addition of a concurrent memory load was limited to same trials. This result implies that the nature of response indicators must be considered in assessing capacity requirements with the sort of dual-task paradigm used in the present investigation. Nevertheless, the fact that the increment in same RT with the addition of a concurrent memory load was greater for subjective relative to real forms accords with expectations derived from the notion that the perception of SCs is more attention demanding than that of real contours. If the interpretation of the present study is correct, then a comprehensive theory of SC perception will most likely be formulated within the top-down perspective of conceptually driven visual information processing.     

视觉注意捕获的快速脱离假说与信号抑制假说

快速脱离假说和信号抑制假说都是将传统的自下而上捕获和自上而下控制结合起来的混合模式假说。快速脱离假说认为突显干扰物总能在第一时间自下而上地捕获注意, 当突显干扰物与任务要求不符时, 注意会迅速脱离该位置。信号抑制假说认为突显干扰物都会产生“注意我”的信号, 当突显干扰物与任务要求不符时, 该信号会被自上而下地抑制以阻止注意捕获发生。前者相关的研究多采用空间线索提示范式和眼动脱离范式, 实验中被试采取独子探测策略, 而后者相关的研究多采用额外单例范式的变式, 实验中被试采取特征探测策略。未来研究应采用不同的刺激类型和实验方法进一步为两个假说提供证据支持, 同时要关注奖赏、训练等因素对“捕获-脱离”和“信号-抑制”的影响。     

基于fMRI的自上而下字母加工神经机制的研究

人们在识别自己所熟悉的物体时, 不仅依赖于对输入信息的感知而且还会受到自上而下调节机制的影响。研究者基于功能磁共振成像(fMRI), 利用虚幻探测范式对自上而下字母加工的神经网络进行研究。该研究要求被试从纯噪声(实际没有任何字母)中探测字母。通过对fMRI数据进行心理生理交互效应分析, 发现当被试从纯噪声图片中“看”到字母时, 多个脑区的活动由于受到来自于右侧梭状回的影响而加强。该发现表明自上而下的字母加工网络不但包含负责字母形状和语音加工的脑区, 还涉及一些负责高级认知加工的区域。     

Trial-by-trial adjustments in control triggered by incidentally encoded semantic cues

Cognitive control mechanisms provide the flexibility to rapidly adapt to contextual demands. These contexts can be defined by top-down goals—but also by bottom-up perceptual factors, such as the location at which a visual stimulus appears. There are now several experiments reporting contextual control effects. Such experiments establish that contexts defined by low-level perceptual cues such as the location of a visual stimulus can lead to context-specific control, suggesting a relatively early focus for cognitive control. The current set of experiments involved a word–word interference task designed to assess whether a high-level cue, the semantic category to which a word belongs, can also facilitate contextual control. Indeed, participants exhibit a larger Flanker effect to items pertaining to a semantic category in which 75% of stimuli are incongruent than in response to items pertaining to a category in which 25% of stimuli are incongruent. Thus, both low-level and high-level stimulus features can affect the bottom-up engagement of cognitive control. The implications for current models of cognitive control are discussed.