Computational principles of working memory in sentence comprehension

Understanding a sentence requires a working memory of the partial products of comprehension, so that linguistic relations between temporally distal parts of the sentence can be rapidly computed. We describe an emerging theoretical framework for this working memory system that incorporates several independently motivated principles of memory: a sharply limited attentional focus, rapid retrieval of item (but not order) information subject to interference from similar items, and activation decay (forgetting over time). A computational model embodying these principles provides an explanation of the functional capacities and severe limitations of human processing, as well as accounts of reading times. The broad implication is that the detailed nature of cross-linguistic sentence processing emerges from the interaction of general principles of human memory with the specialized task of language comprehension.     

发展性阅读障碍与知觉加工

近年来许多行为实验和神经生理学实验都发现 ,发展性阅读障碍与基本知觉障碍有关。在视觉领域研究者提出了巨细胞障碍假设 ,这种假设认为阅读障碍者视觉神经系统中的巨细胞障碍导致他们对某种类型的视觉刺激加工存在困难 ,进而影响阅读。在听觉领域研究发现阅读障碍者加工快速、系列、短暂呈现的声音刺激存在障碍。研究者认为阅读障碍者加工快速刺激输入障碍反映了普遍的时间知觉障碍。这方面的研究发展非常迅速 ,理论观点非常明确 ,并且直接与内在的神经机制相联系 ,形成了与传统的“语言障碍”理论迥然不同的“知觉障碍”理论。“知觉障碍”理论综合了行为、认知和神经等多个层次的研究 ,反映了神经科学发展所带来的巨大影响和认知加工模块化理论的渐渐衰退。     

Processing polarity: how the ungrammatical intrudes on the grammatical

A central question in online human sentence comprehension is, “How are linguistic relations established between different parts of a sentence?” Previous work has shown that this dependency resolution process can be computationally expensive, but the underlying reasons for this are still unclear. This article argues that dependency resolution is mediated by cue‐based retrieval, constrained by independently motivated working memory principles defined in a cognitive architecture. To demonstrate this, this article investigates an unusual instance of dependency resolution, the processing of negative and positive polarity items, and confirms a surprising prediction of the cue‐based retrieval model: Partial‐cue matches—which constitute a kind of similarity‐based interference—can give rise to the intrusion of ungrammatical retrieval candidates, leading to both processing slow‐downs and even errors of judgment that take the form of illusions of grammaticality in patently ungrammatical structures. A notable achievement is that good quantitative fits are achieved without adjusting the key model parameters.     

A comparison of conscious and automatic memory processes for picture and word stimuli: a process dissociation analysis

Four experiments were conducted to evaluate explanations of picture superiority effects previously found for several tasks. In a process dissociation procedure (Jacoby, 1991) with word stem completion, picture fragment completion, and category production tasks, conscious and automatic memory processes were compared for studied pictures and words with an independent retrieval model and a generate-source model. The predictions of a transfer appropriate processing account of picture superiority were tested and validated in "process pure" latent measures of conscious and unconscious, or automatic and source, memory processes. Results from both model fits verified that pictures had a conceptual (conscious/source) processing advantage over words for all tasks. The effects of perceptual (automatic/word generation) compatibility depended on task type, with pictorial tasks favoring pictures and linguistic tasks favoring words. Results show support for an explanation of the picture superiority effect that involves an interaction of encoding and retrieval processes.     

Categorization by schema relations and perceptual similarity in 5-year-olds and adults: A study in vision and in audition

This research explores the way in which young children (5 years of age) and adults use perceptual and conceptual cues for categorizing objects processed by vision or by audition. Three experiments were carried out using forced-choice categorization tasks that allowed responses based on taxonomic relations (e.g., vehicles) or on schema category relations (e.g., vehicles that can be seen on the road). In Experiment 1 (visual modality), prominent responses based on conceptually close objects (e.g., objects included in a schema category) were observed. These responses were also favored when within-category objects were perceptually similar. In Experiment 2 (auditory modality), schema category responses depended on age and were influenced by both within- and between-category perceptual similarity relations. Experiment 3 examined whether these results could be explained in terms of sensory modality specializations or rather in terms of information processing constraints (sequential vs. simultaneous processing).     

Cognitive Load During Problem Solving: Effects on Learning

Considerable evidence indicates that domain specific knowledge in the form of schemas is the primary factor distinguishing experts from novices in problem-solving skill. Evidence that conventional problem-solving activity is not effective in schema acquisition is also accumulating. It is suggested that a major reason for the ineffectiveness of problem solving as a learning device, is that the cognitive processes required by the two activities overlap insufficiently, and that conventional problem solving in the form of means-ends analysis requires a relatively large amount of cognitive processing capacity which is consequently unavailable for schema acquisition. A computational model and experimental evidence provide support for this contention. Theoretical and practical implications are discussed.     

语言类比推理的神经机制：来自ERP研究的证据

实验通过“A:B::C:D”范式, 采用事件相关电位技术, 考察了语言类比推理的神经机制。实验结果显示：图式生成阶段诱发出N400和P300成分, 反映了类比源域的词对概念通达和词对关系抽取的加工过程; 类比映射阶段诱发出N400和晚期负成分LNC, 反映了类比目标域前项词汇概念意义的激活, 以及将已获取的图式关系类比映射于目标域, 并进行推理的加工过程。研究结果表明, 语言类比推理的神经机制复杂, 牵涉到一系列认知加工步骤; LNC成分与类比映射阶段的加工关系密切, 其波幅和头皮分布的广泛性情况与类比映射关系的复杂程度成正比。     

Expertise and Strategies for the Identification of the Main Ideas in Document Indexing

This research project examined strategies used by indexers in identifying important concepts in scientific books. Indexing consists of employing a controlled terminology to express the important ideas contained in a given document. Twenty indexers of varying types and degrees of expertise indexed four books, noting, first, terms representing the main ideas, and then the indexing terms taken from a documentary language. The indexers not familiar with the content domain of the books identified fewer concepts than the indexers familiar with the domain, and based their judgements on surface-level features of the information. Prior knowledge of the experiment's documentary language guided the choice of some concepts, which could be translated into controlled terms, resulting in more rapid identification. These results showed that identifying important concepts could be due to perceptual processing based on specific cues, as well as conceptual processing based on prior knowledge of the documentary language and the domain to be indexed.     

Memory retrieval tasks determine the serial position curves of linear orders with categorical structures

I examined 2 different views on organization of linear order information in memory: the linear schema view and the hierarchical structure view. The linear schema view holds that there is a strong tendency in memory to organize an array of transitively related elements into a unidimensional order. The hierarchical structure view maintains that the transitively related elements are organized in memory in a hierarchy of items. I proposed an input structure and retrieval compatibility hypothesis as a coherent explanation for the contradictory views on the memory organization of serial elements. I argue that the organization of linear order information in memory is determined by the nature of the memory retrieval task used. For example, a comparative judgment task is more compatible with a unidimensional structure, whereas a sequential recall or serial position identification task is more compatible with a hierarchical organization. The input structure and retrieval compatibility concept can also explain why dichotomous categories imposed on a linear order play very little role in comparative judgments.     

Neural activation patterns during retrieval of schema‐related memories: differences and commonalities between children and adults

Schemas represent stable properties of individuals’ experiences, and allow them to classify new events as being congruent or incongruent with existing knowledge. Research with adults indicates that the prefrontal cortex (PFC) is involved in memory retrieval of schema‐related information. However, developmental differences between children and adults in the neural correlates of schema‐related memories are not well understood. One reason for this is the inherent confound between schema‐relevant experience and maturation, as both are related to time. To overcome this limitation, we used a novel paradigm that experimentally induces, and then probes for, task‐relevant knowledge during encoding of new information. Thirty‐one children aged 8–12 years and 26 young adults participated in the experiment. While successfully retrieving schema‐congruent events, children showed less medial PFC activity than adults. In addition, medial PFC activity during successful retrieval correlated positively with children's age. While successfully retrieving schema‐incongruent events, children showed stronger hippocampus (HC) activation as well as weaker connectivity between the striatum and the dorsolateral PFC than adults. These findings were corroborated by an exploratory full‐factorial analysis investigating age differences in the retrieval of schema‐congruent versus schema‐incongruent events, comparing the two conditions directly. Consistent with the findings of the separate analyses, two clusters, one in the medial PFC, one in the HC, were identified that exhibited a memory × congruency × age group interaction. In line with the two‐component model of episodic memory development, the present findings point to an age‐related shift from a more HC‐bound processing to an increasing recruitment of prefrontal brain regions in the retrieval of schema‐related events.     

Elucidating the mental processes underlying the direct retrieval of autobiographical memories

The literature on autobiographical memory retrieval has directed much attention to the concepts of direct retrieval (fast, automatic retrieval) and generative retrieval (slower, deliberative/strategic retrieval). Among the many findings reported on these phenomena, their relative prevalence has stood out as a central feature in many studies, with most studies reporting the frequency of direct retrieval as equal to or exceeding generative retrieval. In this study, we used the retrieve-aloud procedure (a method where participants verbalize their thoughts while retrieving) to delve more deeply into the nature of reports of ubiquitous direct retrieval. We hypothesized that much of the direct retrieval reported in literature is not bona fide direct retrieval (i.e., seemingly automatic retrieval), but is a combination of other retrieval processes, including generative-like retrieval processes. Our results supported this view, showing that less than one-half of all of the observed direct retrievals were bona fide direct retrieval, while the rest were a form of generative retrieval, or fell somewhere in between direct and generative retrieval. We argue that the results suggest that the prevalence of direct retrieval may be overestimated in the literature, and we further propose an alternative classification schema for direct retrievals.     

Measuring automatic retrieval

A variety of procedures have been used to assess automatic retrieval effects on memory, including implicit memory tests and the process dissociation approach. Theoretical concerns with each are summarized prior to describing a procedure for evaluating automatic retrieval that is based on retrieval speed. Specifically, in a speeded implicit task, participants were encouraged to complete word stems using strictly automatic retrieval by presenting several practice test trials that did not allow responding based on previously studied items and by encouraging speed of responding. This speeded implicit task was compared with a condition in which conscious retrieval of studied information was not possible and a condition in which conscious retrieval was required, providing converging evidence to support the hypothesis that the speeded implicit procedure can yield pure estimates of automatic retrieval. Furthermore, evidence from a standard implicit memory task yielded comparable data that suggests that participants engaged automatic retrieval processes on this task also.     

The simpler syntax hypothesis

What roles do syntax and semantics have in the grammar of a language? What are the consequences of these roles for syntactic structure, and why does it matter? We sketch the Simpler Syntax Hypothesis, which holds that much of the explanatory role attributed to syntax in contemporary linguistics is properly the responsibility of semantics. This rebalancing permits broader coverage of empirical linguistic phenomena and promises a tighter integration of linguistic theory into the cognitive scientific enterprise. We suggest that the general perspective of the Simpler Syntax Hypothesis is well suited to approaching language processing and language evolution, and to computational applications that draw upon linguistic insights.     

Measuring automatic retrieval in a conceptual priming task

The speeded response technique has demonstrated that priming in perceptual memory tasks can occur through automatic retrieval that is uncontaminated by conscious retrieval (pure automatic retrieval). This work assesses whether priming in a conceptual task (category exemplar generation) can occur through pure automatic retrieval using the same technique. Automatic retrieval estimates obtained using the speeded response technique were compared to those obtained using more traditional measures (implicit memory and process dissociation procedure [PDP]). Similar estimates of automatic retrieval were obtained for speeded, implicit, and PDP groups following shallow processing. However, higher estimates of automatic retrieval were obtained following deep processing in the speeded and implicit conditions compared to the PDP condition. Advantages for using the speeded response technique to index automatic memory are discussed.     

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.     

The repetition defect in conduction aphasia: Mnestic or linguistic?

Repetition difficulty is the cardinal feature of conduction aphasia. Traditionally this disorder has been considered secondary to a deficit in linguistic processing but recently a number of investigators have interpreted such cases as consequent upon a short-term memory difficulty in the auditory—verbal domain. We present here the case of a 24-year-old patient with conduction aphasia, whose symptom picture closely resembles those patients whose difficulties have been attributed to mnestic factors. Our patient's performance improved dramatically when stimuli were presented more slowly or when they were familiar, when the task involved matching rather than language production, and when multiple choices were provided for missed items. More crucially the patient's errors in repetition were primarily paraphasic and sequential; and repetition of single nonsense words was severely impaired. Taken together these results suggest that the patient's disorder, and perhaps that of other cases as well, would be better viewed as a linguistic deficit, specifically in the processing, synthesis, and ordering of phonemes. A tentative model for repetition disorder is proposed.     

Pythagorean distance and the judged similarity of schematic stimuli

Independent groups of Ss rated the similarity of pairs of patterns belonging to the same class, either bef ore or af ter a discrimination task of schematic concept formation (SCF). Mean similarity increased as a function of SCF pretraining. A linear relationship was found between a Pythagorean distance measure on the patterns and subjective similarity of pairs of stimuli (r=.88). No such relationship was obtained from an analysis of judgments from a group that viewed random, nonschematic stimuli. A secondary analysis of the discrimination judgments in the SCF task showed that the Pythagorean distance measure was predictive of judgments on pairs of stimuli from the same schema family, but the relationship did not hold for pairs representing two different schemata. Multidimensional scaling analyses indicated that mildly deviant schematic stimuli were perceived to be instances of a single family. The dimensions describing a schema cluster appeared to be specific to the sample of stimuli. A tendency for the Kruskal procedures to collapse certain types of stimulus clusters was observed and discussed.     

Grammatical encoding in aphasia: evidence from a "processing prosthesis"

Agrammatic aphasia is characterized by severely reduced grammatical structure in spoken and written language, often accompanied by apparent insensitivity to grammatical structure in comprehension. Does agrammatism represent loss of linguistic competence or rather performance factors such as memory or resource limitations? A considerable body of evidence supports the latter hypothesis in the domain of comprehension. Here we present the first strong evidence for the performance hypothesis in the domain of production: an augmentative communication system that markedly increases the grammatical structure of agrammatic speech while providing no linguistic information, functioning merely to reduce on-line processing demands.     

Different selection principles of freestanding and bound morphemes in language production

Freestanding and bound morphemes differ in many (psycho)linguistic aspects. Some theorists have claimed that the representation and retrieval of freestanding and bound morphemes in the course of language production are governed by similar processing mechanisms. Alternatively, it has been proposed that both types of morphemes may be selected for production in different ways. In this article, the authors first review the available experimental evidence related to this topic and then present new experimental data pointing to the notion that freestanding and bound morphemes are retrieved following distinct processing principles: freestanding morphemes are subject to competition, bound morphemes not.     

Consciousness as recursive, spatiotemporal self-location

At the phenomenal level, consciousness arises in a consistently coherent fashion as a singular, unified field of recursive self-awareness (subjectivity) with explicitly orientational characteristics—that of a subject located both spatially and temporally in an egocentrically-extended domain. Understanding these twin elements of consciousness begins with the recognition that ultimately (and most primitively), cognitive systems serve the biological self-regulatory regime in which they subsist. The psychological structures supporting self-located subjectivity involve an evolutionary elaboration of the two basic elements necessary for extending self-regulation into behavioral interaction with the environment: an orientative reference frame which consistently structures ongoing interaction in terms of controllable spatiotemporal parameters, and processing architecture that relates behavior to homeostatic needs via feedback. Over time, constant evolutionary pressures for energy efficiency have encouraged the emergence of anticipative feedforward processing mechanisms, and the elaboration, at the apex of the sensorimotor processing hierarchy, of self-activating, highly attenuated recursively-feedforward circuitry processing the basic orientational schema independent of external action output. As the primary reference frame of active waking cognition, this recursive self-locational schema processing generates a zone of subjective self-awareness in terms of which it feels like something to be oneself here and now. This is consciousness-as-subjectivity.