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PubMedDate not supplied

False memories and semantic lexicon arrangement.

A description of semantic lexicon arrangement is a central goal in examinations of language processing. There are a number of ways in which this description has been cast and a host of different mechanisms in place for providing operational descriptions (e.g., feature sharing, category membership, associations, and co-occurrences). We first review two views of the structure of semantic space and then describe an experiment that attempts to adjudicate between these two views. The use of a false memory paradigm provides us with evidence that supports the notion that the semantic lexicon is arranged more by association than by categories or features.

Analysis of Variance↗

PubMedDate not supplied

What do category-specific semantic deficits tell us about the representation of lexical concepts?

A reassessment of category-specific semantic deficits in light of their contribution to a theory of the representation of lexical concepts is proposed. Two theories are examined: one, held by the majority of researchers in the field, claims that concepts are represented by sets of features; another, in contrast, claims that concepts are atomic representations. An analysis of category-specific semantic deficits in terms of inferential relations (of the meaning-postulates type) between atomic concepts is elaborated. It is argued that this theory can better account for the pattern of performance exhibited by patients with semantic deficits.

Cognition↗

PubMedDate not supplied

Morphological priming: the role of prime duration, semantic transparency, and affix position.

Patterns of facilitation in three lexical decision studies reveal several properties of morphologically complex words that influence processing. In one study, effects of morphological (VOWED-VOW) similarity are contrasted with effects of either semantic (PLEDGE-VOW) or orthographic (VOWEL-VOW) similarity at two prime durations to show the distinctiveness of morphological processing. In a second study, we compare morphologically complex forms that are semantically transparent (CASUALLY-CASUALNESS) with opaque forms (CASUALTY-CASUALNESS) and show that opaque relatives are more similar to VOWEL-VOW type pairs than to transparent relatives. In the third study, we examine facilitation for complex targets (CALCULATION) preceded by prefixed (MISCALCULATE) and suffixed (CALCULATOR) relatives and show that the position of the base morpheme influences processing under cross-modal but not under purely visual presentation conditions. Taken collectively, under comparable presentation conditions, semantic transparency but not base morpheme position constrains morphological processing.

Humans↗

PubMed2000

Rapid word identification in pure alexia is lexical but not semantic.

Following the notion that patients with pure alexia have access to two distinct reading strategies-letter-by-letter reading and semantic reading-a training program was devised to facilitate reading via semantics in a patient with pure alexia. Training utilized brief stimulus presentations and required category judgments rather than explicit word identification. The training was successful for trained words, but generalized poorly to untrained words. Additional studies involving oral reading of nouns and of functors also resulted in improved reading of trained words. Pseudowords could not be trained to criterion. The results suggest that improved reading can be achieved in pure alexia by pairing rapidly presented words with feedback. Focusing on semantic processing is not essential to this process. It is proposed that the training strengthens connections between the output of visual processing and preexisting orthographic representations.

Dyslexia↗

PubMed2001

Visual field asymmetries for rhyme and semantic tasks in fluent and nonfluent bilinguals.

A tachistoscopic study investigated hemispheric specialization among fluent and nonfluent bilinguals for rhyme and semantic tasks in both their languages. Fluent bilinguals gave faster responses and made fewer errors in their responses to the words presented in the RVF(LH) while the opposite happened for nonfluent, which indicates greater RH participation in the first stages of a second language. Fluent bilinguals performed better not only in the second but also in their native language, suggesting superior language skills on the part of fluent bilinguals. A LVF(RH) superiority was obtained for semantic tasks, indicating RH participation in semantic judgments. Another finding was a high ratio of first-born children among fluent bilinguals, potentially explained in terms of parental attitudes toward first- versus later born children.

Adult↗

PubMedDate not supplied

The contribution of frequency and semantic similarity to morphological processing.

This research investigated the role of frequency and semantic factors in the processing of morphologically complex words. Unaffixed targets were immediately preceded by either inflected or derived primes that were either high or low in frequency. In Experiment 1, low-frequency inflections and derivations produced equivalent priming effects, whereas high-frequency inflections produced more priming than derivations. In Experiment 2, both semantic and morphological priming varied as a function of SOA (50, 150, and 250 ms). The difference in priming of inflections and derivations increased as SOA increased. Results suggest that frequency and semantic similarity interactively modulate the magnitude of morphological priming and, by inference, affect the processing of morphologically complex words. Dual-route and connectionist accounts are discussed.

Cognition↗

PubMed1998

Adding apples and oranges: alignment of semantic and formal knowledge.

We show that the same mechanism that mediates analogical reasoning (i.e., structural alignment) leads to interpretive "content effects" in reasoning about arithmetic word problems. Specifically, we show that both college students and textbook writers tend to construct arithmetic word problems that maintain systematic correspondence between the semantic relations that people infer from pairs of real-world objects (e.g., apples and baskets support the semantic relation CONTAIN [content, container]) and mathematical relations between arguments of arithmetic operations (e.g., DIVIDE [dividend, divisor]). Such relational alignments, to which we refer here as semantic alignments, lead to selective and sensible application of abstract formal knowledge. For example, people usually divide apples among baskets rather than baskets among apples, and readily add apples and oranges but refrain from adding apples and baskets.

Cognition↗

PubMed1999

Dual-process model in semantic priming: A functional imaging perspective.

In this positron emission tomography study, we investigated the neural correlates of semantic priming, where response to a word is facilitated when preceded by a semantically related word. Nine normal subjects were scanned while performing a lexical decision task. Within this condition, the proportion of related prime-target word pairs was varied across scans from 0 to 100%. The control task involved letter decision on consonant letter strings, controlling orthographic processing and response selection. First, lexical decision (relative to letter decision) activated regions previously observed in lexicosemantic tasks, i.e., the left anterior and inferior temporal lobe and left inferior frontal gyrus. Behavioral analysis confirmed significant facilitation of lexical decision to related targets (mean priming effect 68 ms). It also suggested the contribution of both automatic and strategic processes, consistent with theoretical accounts of priming. Automatic priming was indicated by consistent RTs to related targets irrespective of the proportion of related word pairs per scan. Strategic processing was indicated by decreases in RTs to nonwords as the proportion of related targets increased. Nonlinear correlational analysis of cerebral activity during lexical decision revealed a neurophysiological correlate of these behavioral effects in (i) the left anterior temporal lobe (BA 38), a region involved in lexicosemantic processing; (ii) the anterior cingulate cortex, right premotor region (BA 6), and right superior parietal lobe (BA 7), regions associated with attentional processes. We conclude that in this experimental context, semantic priming involves both automatic and strategic processing.

Adult↗

PubMed2002

N400-like magnetoencephalography responses modulated by semantic context, word frequency, and lexical class in sentences.

Words have been found to elicit a negative potential at the scalp peaking at approximately 400 ms that is strongly modulated by semantic context. The current study used whole-head magnetoencephalography (MEG) as male subjects read sentences ending with semantically congruous or incongruous words. Compared with congruous words, sentence-terminal incongruous words consistently evoked a large magnetic field over the left hemisphere, peaking at approximately 450 ms. Source modeling at this latency with conventional equivalent current dipoles (ECDs) placed the N400 m generator in or near the left superior temporal sulcus. A distributed solution constrained to the cortical surface suggested a sequence of differential activation, beginning in Wernicke's area at approximately 250 ms, spreading to anterior temporal sites at approximately 270 ms, to Broca's area by approximately 300 ms, to dorsolateral prefrontal cortices by approximately 320 ms, and to anterior orbital and frontopolar cortices by approximately 370 ms. Differential activity was exclusively left-sided until >370 ms, and then involved right anterior temporal and orbital cortices. At the peak of the N400 m, activation in the left hemisphere was estimated to be widespread in the anterior temporal, perisylvian, orbital, frontopolar, and dorsolateral prefrontal cortices. In the right hemisphere, the orbital, as well as, weakly, the right anterior temporal cortices were activated. Similar but weaker field patterns were evoked by intermediate words in the sentences, especially to low-frequency words occurring in early sentence positions where there is little preceding context. The locations of the N400 m sources identified with the distributed solution correspond well with those previously demonstrated with direct intracranial recordings, and suggested by functional magnetic resonance imaging (fMRI). These results help identify a distributed cortical network that supports online semantic processing.

Adult↗

PubMed1990

Semantic context and figure-ground organization.

The semantic-priming paradigm was used to investigate the effect of semantic context on the latency to identify visually ambiguous and unambiguous targets. Ambiguous targets had reversible figure-ground organizations analogous to Rubin's vase-profiles picture in which the figural vase is shaped by the same contour that, if reassigned, shapes two figural profiles. The two organizations of the ambiguous targets were either a series of black irregular shapes or a familiar word in white letters; subjects were required to achieve the latter organization. Unambiguous target words were not reversible. Related primes, unlike unrelated primes, facilitated the identification of both types of target; but the magnitude of facilitation was greater for ambiguous targets. The results demonstrate that semantic context influences the speed of figure-ground organization and add perceptual ambiguity to the target manipulations that interact with context to affect encoding.

Adult↗

PubMed1993

A graph theory model of the semantic structure of attitudes.

The semantic structure underlying the attitudes of pretreatment and posttreatment drug addicts was modeled using a network analysis of free word associations. Measures of graph theoretic properties were used to assess structural differences in the associative networks of the two populations. These measures modeled the information processes of associative networks proposed in the spreading activation theory of semantic processing. As expected based on graph theory, the structure of the associative networks of posttreatment subjects was more dense, less constrained, and more hierarchically organized by the self concept. In a test of the network model, the subjects' evaluations of concepts in the associative network were found to be a function of their evaluations of semantically similar concepts. Although preliminary and limited, the results suggest that graph theory may provide a broad mathematical foundation for diverse models of cognitive systems.

Attitude↗

PubMed1994

Why and when do some language-impaired children seem talkative? A study of initiation in conversations of children with semantic-pragmatic disorder.

Six language-impaired children fitting the clinical picture of semantic-pragmatic disorder (mean age 11 years) engaged in conversations with adults in four situations varying in terms of familiarity of the interlocutor (familiar or unfamiliar) and type of setting (interview or toy exploration). These children did not produce more utterances or longer utterances than normally developing children of similar age or ability, but they were more likely to produce utterances that served the conversational function of initiating, rather than responding or acknowledging. This tendency was most pronounced in the toy setting. There was a nonsignificant trend for control children to initiate more with a familiar than with an unfamiliar adult, but no such tendency in the semantic-pragmatic group. A high rate of initiations in children with semantic-pragmatic disorder cannot be regarded as an unusual behavior provoked by the demands of the interview setting, as it is even more apparent during toy exploration, where the child is under less pressure to respond to adult questions.

Adult↗

PubMedDate not supplied

Locus of semantic generalization of the galvanic skin response and possible inhibitory influence of conditional stimuli upon unconditional response following conditioning with innocuous and noxious unconditional stimuli.

Two different problems were investigated using the GSR index of the orienting reflex (OR): 1) the locus of semantic generalization; and 2) a possible inhibitory influence of the CS upon the UCR. Two experiments were conducted. One experiment employed an innocuous USC, and a second similar experiment used a loud noise as the UCS. Unidirectional word associates were employed in the test of the direction of semantic generalization. Constant and varying CS words were used to test the possible inhibitory influence of the CS upon the UCR. Evidence was obtained of semantic generalization occurring in the training and in the test situation. There was no evidence of the CS developing inhibition over the UCR. Theoretical interpretation of both phenomena were considered. The need for developing theories of conditioning of the OR in humans was emphasized in contrast to current efforts to apply inappropriate cognitive animals learning theories which fail to consider biologic constraints.

Adult↗

PubMed1997

[Event-related potentials in semantic speech processing by schizophrenic patients].

Event-related potentials (ERPs) can be used for high-resolution mental chronometry. For about 15 years, this method has been applied to the study of linguistic phenomena. Semantic incongruency produces a negative component at about 400 ms after stimulus onset, the N400. We measured the N400 component in 20 schizophrenic patients and 20 normal control subjects performing a lexical decision task in which semantic distance between prime and target was varied. The results provide evidence of dysfunctional semantic information processing in schizophrenic patients, and reaction time data from previous studies can be interpreted within an electrophysiological framework. The N400 amplitude and latency data support recent spreading activation models of schizophrenic language dysfunction.

Adult↗

PubMed2002

Semantics affect the planning but not control of grasping.

The semantic meaning of a word label printed on an object can have significant effects on the kinematics of reaching and grasping movements directed towards that object. Here, we examined how the semantics of word labels might differentially affect the planning and control stages of grasping. Subjects were presented with objects on which were printed either the word "LARGE" or "SMALL." When the grip aperture in the two conditions was compared, an effect of the words was found early in the reach, but this effect declined continuously as the hand approached the target. This continuously decreasing effect is consistent with a planning/control model of action, in which cognitive and perceptual variables affect how actions are planned but not how they are monitored and controlled on-line. The functional and neurological bases of semantic effects on planning and control are discussed.

Hand Strength↗

PubMed2006

Seeing red primes tomato: evidence for comparable priming from colour and colour name primes to semantically related word targets.

There is ample evidence that an independent processing stream exists that subserves the perception and appreciation of colour. Neurophysiological research has identified separate brain mechanisms for the processing of wavelength and colour, and neuropsychological studies have revealed selective colour disorders, such as achromatopsia, colour agnosia, and colour anomia. The aim of the present study is to investigate whether the perception of colour may, despite its independent processing, influence other cognitive functions. Specifically, we investigate the possibility that the perception of a colour influences higher order processes such as the activation of semantically related concepts. We designed an associative priming task involving a colour prime (e.g. a red patch or the word RED) and a lexical decision response to a semantically related ('tomato' vs. 'timato') or unrelated ('grass' vs. 'griss') word target. The results of this experiment indicate that there is comparable facilitation of accessing colour-related semantics through the perception of a colour or the reading of a colour name. This suggests that colour has a direct effect on higher order level, cognitive processing. These results are discussed in terms of current models of colour processing.

Adult↗

PubMed2004

The advantage of first mention in Korean the temporal contributions of syntactic, semantic, and pragmatic factors.

Using Korean, we investigated how syntactic, semantic, and pragmatic factors influence the representation of a sentence, in particular, the relative accessibility of different components of a sentence representation. In six experiments, participants performed a probe recognition task after reading each of a series of sentences. We manipulated the rate at which each word of the sentence was presented (250 and 500ms) and the interval between the sentence-final word and the probe-recognition test word (immediate, 500ms delay, and 1000ms delay). We also manipulated the syntactic position (subject versus object), semantic role (agent versus patient), and order of mention (first- versus second-mentioned participant) of the probed item. Pragmatic factors (the order of mention) strongly influenced accessibility immediately and through the longest delay, whereas syntactic and semantic factors had little effect.

Humans↗

PubMed2005

Comprehending semantic and grammatical violations in Italian. N400 and P600 comparison with visual and auditory stimuli.

Arguments about the existence of language-specific neural systems and specifically about the independence of syntactic and semantic processing have focused on the event-related brain measures (ERPs) as tool to monitoring moment-by-moment the cognitive processes underlaid. In the present experiments, the available evidence indicates that the ERP response to semantic anomalies is at least partially distinct from the ERP response to syntactic anomalies and that two distinct processes are activated in sentences comprehension. ERPs were recorded from 10 electrodes while subjects read (Experiment 1) or listened (Experiment 2) to sentences containing semantic or syntactic violations. Final-words that were inconsistent with the sentence context elicited a negative-going wave at about 400 ms poststimulus, whereas penultimate-word incongruous with the grammatical structure (subject-verb non-agreement) elicited a positive-going wave about 600ms poststimulus. No differences based on the perceptual modality of the stimulus (visual or auditory) nor different ERP correlates as a function of task-relevance (explicit/implicit task induction) were found The implications of our results for Italian language are explained.

Adult↗