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PubMed1976

The differential effects of semantic, acoustic, and nonverbal distraction on Korsakoff patients' verbal retention performance.

Korsakoff and alcoholic control patients' verbal retention performance was assessed following either acoustic, semantic, or nonverbal distractor activity. Both patient groups were similarly affected by the degree of relatedness between the distractor and the memoranda. Semantic distraction produced more verbal forgetting than acoustic, which in turn, caused more forgetting than the nonverbal tasks. The Korsakoff patients' verbal retention, however, became increasingly impaired, relative to the controls, as the level of similarity between the distraction and the memoranda increased. These results suggest that Korsakoff patients have difficulty performing verbal analyses which incorporated the distinctive physical, phonemic and semantic features of the memoranda into the development of their verbal memory traces.

Acoustics↗

PubMed1979

The relationships between conceptual and semantic-lexical disorders in aphasia.

A nonverbal test of conceptual thinking was administered to 55 normal controls and to 203 patients with monohemispheric brain lesions (74 aphasics and 129 nonaphasic brain-damaged patients), in order to study the relationships between conceptual impairment of aphasic patients and breakdown of the semantic-lexical level of integration of language. A very high number of aphasic patients (54 out of 74) and a limited number of nonaphasic brain-damaged subjects (31 out of 129) obtained a pathological score on the test of conceptual thinking, but only some components of the aphasic symptomatology seemed closely linked to the conceptual disorder. In fact a non-significant relationship was found between conceptual impairment and: ("fluent" or "non-fluent") clinical type of aphasia; severity of aphasic disturbance. On the contrary, a strong relationship was found between conceptual disorder and impairment of the semantic-lexical level of integration of language. These findings seem to show that conceptual disturbance and semantic-lexical troubles are closely linked in aphasia.

Aphasia↗

PubMed1982

Schizophrenia and semantic aphasia: a clinical comparison.

In recent years, there has been an emerging body of evidence which suggests that some types of schizophrenia may have a neurologic pathogenesis. This paper is addressed to the exploration of cortical mechanisms in schizophrenia by comparing the language disturbances of chronic schizophrenia with those of semantic aphasia. While there is little commonality between schizophrenic word-salad and jargon aphasia, there are similarities between schizophrenic agrammatism and semantic aphasia in terms of impressive and expressive grammar and in the manifestation of paraphasia and paralogia. It is concluded that while no cortical lesions are likely in schizophrenia, there may be a neurologic arousal/attention abnormality which impairs cortical efficiency, giving rise to a language disturbance symptomatically similar to, but pathogenically different from semantic aphasia.

Aphasia↗

PubMed1984

Neurocybernetic basis of semantic processes.

Although semantics cannot be reduced to neurophysiology, it must have however a certain neurophysiologic basis and this paper deals with, that neurophysiologic basis which, in fact, has a neurocybernetic basis. The paper first approaches the relations between information and signification and their part within the nervous system's work. Then, it analyses semantic function discoverying neurocybernetic mechanisms which can be proper not only to the conventional signs but also to the objects and phenomena which in turn can play the sign's part. Finally, semantic levels of the nervous system, beginning with the most elementary level of unity, as letters are, and up to the level of the highest ideas and concepts the brain is working with, are described.

Brain↗

PubMed1987

Auditory P3 correlates of phonemic and semantic processing.

Auditory evoked potentials were recorded in twelve healthy subjects using phonemic and semantic word tasks. The late positive component (P3), analogous to tonal P300, varied as a function of cognitive task with increased latency and amplitude associated with semantic processing. These data are consistent with levels of processing theories in which semantic analysis is associated with a greater elaboration of stimulus evaluation.

Adult↗

PubMed1995

Hemispheric semantics: effects on pictorial organization of patients with unilateral brain damage.

Memory for incongruous scenes (violating "knowledge-of-the-world") versus unorganized (jumbled) arrays was tested in war veterans with unilateral penetrating missile wounds of the brain in order to assess hemispheric differences in semantic schemas in long-term memory. Left brain-damaged (LBD) patients were selectively impaired in remembering unorganized scenes compared to right brain-damage (RBD) patients. There was no significant LBD-RBD difference in remembering incongruous scenes. The results confirm the presence of hemispheric asymmetry for semantic schemas in long-term memory, even in pictorial material. However, some features in the organization of semantic schemas are common to both hemispheres and suggests presence of similar knowledge systems. The asymmetry is discussed in terms of intact left hemisphere specialization for assigning meaning to a visual scene when obvious meaning appears to be absent.

Aged↗

PubMed2006

Semantic inhibition of return is the exception rather than the rule.

Inhibition of return (IOR) has recently been reported for lexical/semantic categories (see, e.g., Fuentes, Vivas, & Humphreys, 1999). The present research examines the impact on semantic IOR of three components: item repetition, item heterogeneity, and spatial variability. Experiments 1 and 2 indicate that lexical/semantic IOR occurs only after extensive repetition. Experiment 2 also shows that semantic IOR is independent of spatial variability. Experiments 3 through 5 show facilitatory rather than inhibitory effects when the item pool is heterogeneous. The results support an episodic account of semantic IOR, according to which inhibitory effects accumulate with massive repetition of homogeneous items.

Humans↗

PubMed2005

Bidirectional semantic priming in the attentional blink.

The time course of semantic priming between two associated words was tracked using rapid serial visual presentation of two synchronized streams of stimuli appearing at about 20 items/sec, each stream including a target word. The two words were semantically related or unrelated and were separated by stimulus onset asynchronies (SOAs) of 0-213 msec. Accuracy in reporting the first target (T1) versus the second target (T2) has been shown to interact dramatically with SOA over this range. The materials were in English in Experiment 1 and Italian in Experiment 2. T1 was semantically primed only at short SOAs, whereas T2 was primed at all SOAs (Experiment 1) or at all SOAs except the shortest one (Experiment 2). The results indicate a strong competition between target words early in processing, with T2 often becoming the first word identified at short SOAs, thus priming T1.

Association↗

PubMed2005

The locus of semantic priming in RSVP target search.

At what stage does semantic priming affect accuracy in target search? In two experiments, participants viewed two streams of stimuli, each including a target word among distractors. Stimulus onset asynchronies (SOAs) between the targets (T1 and T2) ranged from 53 to 213 msec. A word semantically related to one or neither of the targets preceded each trial. In Experiment 1, participants were instructed to report both targets. Although more primed than unprimed targets were reported, there was no cost for unprimed words. A strong interaction between SOA and T1 versus T2 was found, but priming did not interact with either variable. In Experiment 2, only related targets were reported. Performance was similar to that for primed targets in Experiment 1. Semantic priming does not seem to modulate how attentional resources are initially allocated between targets, but instead affects a later stage of processing, the point at which a target word reaches lexical identification.

Fixation, Ocular↗

PubMed2003

The contribution of autobiographical significance to semantic memory.

We examined the importance of autobiographical significance (AS) in the representation and organization of semantic memory by examining which famous people are most likely to be associated with specific personal memories and whether or not this AS can be distinguished from other factors, such as familiarity. Norming studies with 45- to 55-year-old and 65- to 80-year-old participants suggested that AS is distinct from familiarity and that it interacts closely with emotional salience. Furthermore, in a set of experiments, we tested the hypothesis that AS is an important organizing principle in long-term episodic and semantic memory by contrasting performances on tests of recall, recognition, fame judgment, and speeded reading for famous names judged to be of either high or low personal relevance. Participants demonstrated a performance advantage (i.e., enhanced memory and faster responding) for autobiographically significant famous names, regardless of whether their own judgments or others' judgments were used to classify the names. The implications of these findings for models of semantic memory are discussed.

Adult↗

PubMed2001

Perception is a two-way junction: feedback semantics in word recognition.

Feed back semantics refers to whether a specific meaning can be represented by only one word (consistent) or by several words (inconsistent)--that is, whether a word has synonyms (e.g., jail) or not (e.g., milk). Models of word perception that allow feedback activation from semantics to orthography and phonology predict that performance should be worse for words that are feedback inconsistent (words with a synonym) than for words that are feedback consistent (words without a synonym). The present study showed that both naming and lexical decision responses are faster and more accurate to consistent than to inconsistent words. The results provide support for models that allow feedback activation between phonology, orthography, and semantics.

Adult↗

PubMed2001

Maintenance of semantic information in capacity-limited item short-term memory.

We report a semantic effect in immediate free recall, which is localized at recency and is preserved under articulatory suppression but is highly reduced when recall is delayed after an intervening distractor task. These results are explained by a neurocomputational model based on a limited-capacity short-term memory (STM) store, consisting of activated long-term memory representations. The model makes additional predictions about serial position functions in semantically cued recall, indicating capacity limitations caused by a displacement type mechanism, which are confirmed in a second experiment. This suggests that in addition to the phonological component in verbal STM, there is an activation/item-limited component with semantically sensitive representations.

Adult↗

PubMed2005

Semantic similarity and immediate serial recall: is there an effect on all trials?

In immediate serial recall, items are better recalled when they are all drawn from the same semantic category. This is usually accounted for by a two-stage retrieval-based framework, in which, at recall, long-term knowledge is used to reconstruct degraded phonological traces. The category shared by list items would serve as an additional retrieval cue restricting the number of recall candidates. Usually, the long-term search set is not defined, but some authors have suggested an extended search set and others a restricted set that is composed of the most recently presented items. This was tested in an experiment in which participants undertook an immediate serial recall task either alone or under articulatory suppression with either semantically similar or dissimilar lists. A trial-by-trial analysis revealed that, in both quiet and suppression conditions, items from similar lists were better recalled on all the trials, including the first one. In addition, there was no interaction between semantic similarity and trial, indicating that the effect of similarity was of similar size on all the trials. The results are best interpreted within a proposal suggesting an extended long-term search set.

Association Learning↗

PubMed2003

Number-of-features effects and semantic processing.

Participants list many semantic features for some concrete nouns (e.g., lion) and fewer for others (e.g., lime; McRae, de Sa, & Seidenberg, 1997). Pexman, Lupker, and Hino (2002) reported faster lexical decision and naming responses for high number of features (NOF) words than for low-NOF words. In the present research, we investigated the impact of NOF on semantic processing. We observed NOF effects in a self-paced reading task when prior context was not congruent with the target word (Experiment 1) and in a semantic categorization task (concrete vs. abstract; Experiment 2A). When we narrowed our stimuli to include high- and low-NOF words from a single category (birds), we found substantial NOF effects that were modulated by the specificity of the categorization task (Experiments 3A, 3B, and 3C). We argue that these results provide support for distributed representation of word meaning.

Decision Making↗

PubMed2003

Is semantic priming due to association strength or feature overlap? A microanalytic review.

In a recent meta-analysis, Lucas (2000) concluded that there is strong evidence of an overall pure semantic priming effect but no evidence of priming based purely on association. In the present review, I critically examine the individual studies claiming evidence of featural and associative relations in semantic memory. The most important conclusion is that automatic priming appears to be due to both association strength and feature overlap. Mediated associates provide the strongest evidence of automatic associative priming, whereas functional associates, synonyms, and antonyms instead support priming based on feature overlap. In contrast, automatic priming does not occur for category coordinates or perceptually similar items, at least when presented in the visual modality. The status of other relations, such as collocates, episodic relatives, and script relations, is unclear and requires further experimentation. Implications for current models of semantic representation and priming are discussed.

Attention↗

PubMed2003

Spatial iconicity affects semantic relatedness judgments.

Three experiments were conducted to examine whether spatial iconicity affects semantic-relatedness judgments. Subjects made speeded decisions with regard to whether members of a simultaneously presented word pair were semantically related. In Experiment 1, the words were presented one above the other. In the experimental pair, the words denoted parts of larger objects (e.g., ATTIC-BASEMENT). The words were either in an iconic relation with their referents (e.g., ATTIC presented above BASEMENT) or in a reverse-iconic relation (BASEMENT above ATTIC). The reverse-iconic condition yielded significantly slower semantic-relatedness judgments than did the iconic condition. Experiments 2 and 3 showed that this effect did not occur when the words were presented horizontally, thus ruling out that the iconicity effect is due to the order in which the words are read. Two alternative explanations for this finding are discussed.

Conflict, Psychological↗

PubMed2005

Using context to build semantics.

Latent semantic analysis (LSA) is a model of knowledge representation for words. It works by applying dimension reduction to local co-occurrence data from a large collection of documents after performing singular value decomposition on it. When the reduction is applied, the system forms condensed representations for the words that incorporate higher order associations. The higher order associations are primarily responsible for any semantic similarity between words in LSA. In this article, a memory model is described that creates semantic representations for words that are similar in form to those created by LSA. However, instead of applying dimension reduction, the model builds the representations by using a retrieval mechanism from a well-known account of episodic memory.

Association Learning↗

PubMed2004

Semantic context influences memory for verbs more than memory for nouns.

Three experiments revealed that memory for verbs is more dependent on semantic context than is memory for nouns. The participants in Experiment 1 were asked to remember either nouns or verbs from intransitive sentences. A recognition test included verbatim sentences, sentences with an old noun and a new verb, sentences with an old verb and a new noun, and entirely new sentences. Memory for verbs was significantly better when the verb was presented with the same noun at encoding and at retrieval. This contextual effect was much smaller for nouns. Experiments 2 and 3 replicated this effect and provided evidence that context effects reflect facilitation from bringing to mind the same meaning of a verb at encoding and at retrieval. Memory for verbs may be more dependent on semantic context because the meanings of verbs are more variable across semantic contexts than are the meanings of nouns.

Humans↗