Semantic feature representations for normal and aphasic language

Aphasic and non-neurological patients grouped nouns on the basis of similarity of meaning. These word groupings served as input matrices for hierarchical clustering and multidimensional scaling analyses. The emergent structures suggest that, while the normal adult has a number of levels upon which to organize his lexicon, the adult aphasic's lexicon can be characterized as a set of partial entries that are tied to affective and situational data. The results also suggest that semantic feature representations derived from similarity-of-meaning judgments are of relevance in the study of factors which influence actual language performance.     

Semantic representations of word meanings by the cerebral hemispheres

Two priming experiments investigated kind and strength of semantic knowledge underlying known, frontier, and unknown low frequency words. Results from Experiment 1 suggest that known words reflect categorical knowledge, but frontier and unknown words reflect thematic knowledge. Thematic knowledge for frontier words appears to be stronger than that for unknown words. Experiment 2 entailed visual half-field presentation of targets. All facilitory effects were restricted to the lvf/RH, and inhibitory effects to the rvf/LH. Experiment 1 findings were mirrored by the RH. Thematic knowledge appears to precede categorical knowledge for the RH, but the opposite may be true of the LH. Results are also discussed in terms of the RH role in meaning acquisition and metacontrol.     

Trees as memory representations for simple visual patterns

The form of the memory representation for visual patterns consisting of a few line segments was investigated with three tasks. One task was the reproduction of remembered patterns using pencil and paper. The order in which the subparts of those patterns were reproduced was used to make suggestions about possible memory representations for the patterns. The second task involved rating the “goodness” of subparts of the patterns. These ratings were also interpreted as reflecting the underlying representations of the patterns. In the third task, the time required to recognize that a small pattern was part of a larger remembered pattern was used as further evidence about the memory representations of the patterns. The results from all three tasks are consistent with the theory that the memory representations are tree structures. Methods for deriving and comparing tree structures are discussed.     

Semantic control of eye movements in picture scanning during sentence-picture verification

The Weber fraction, (I + Δ)/I, was measured for pure tones which were I presented either homophasically or antiphasically. For both stimuli, the Weber fraction was measured as a function of changes in the level of the standard tone Iand in the phase angle of addition between a test tone and the standard tone. The value, ΔI, in the Weber fraction was defined as that difference between the level of the test-plus-standard and the level of the standard (I) which was required for the listener to discriminate a difference between the standard and the test-plus-standard. In the homophasic case, the Weber fraction remained constant for changes in the phase angle of addition, whereas in the antiphasic condition, the Weber fraction decreased for increasing values of the phase angle of addition. For both the homophasic and antiphasic conditions and at all values of the phase angle of addition, the Weber fraction remained a constant as the value of the standard was varied. These results are in agreement with those obtained in studies involving noise masking, lateralization, and the monaural Weber fraction.     

Semantic clustering as a neuropsychological predictor for amnestic-MCI

ABSTRACT

Recent research has demonstrated that patients with Alzheimer's disease (AD) show deficits in semantic processing when compared to cognitively healthy individuals. This difference is thought to be attributed to losses in higher cortical systems that are predominantly associated with executive functioning. The first aim of the study will be to determine if differences in semantic clustering can accurately differentiate patients with amnestic mild cognitive impairment (aMCI) from cognitively normal (CN) individuals. The second aim will be to determine the extent to which semantic processing might be associated with executive functions. Data from 202 (134 CN, 68 aMCI) participants were analyzed to quantify differences in semantic clustering ratios on the HVLT-R. Study participants ages ranged from 51 to 87 with education ranging from 6 to 20 years. ANCOVA revealed statistically significant differences on semantic clustering ratios (p < .001). Moderate correlations between semantic clustering Category Fluency Test (r = .45) were also found. Statistically significant group differences were also present on Trails-B and WAIS-R Digit Symbol performance (p < .001). Overall, these data indicate that deficits in semantic clustering are present in aMCI patients.     

Semantic clustering as a neuropsychological predictor for amnestic-MCI

Recent research has demonstrated that patients with Alzheimer's disease (AD) show deficits in semantic processing when compared to cognitively healthy individuals. This difference is thought to be attributed to losses in higher cortical systems that are predominantly associated with executive functioning. The first aim of the study will be to determine if differences in semantic clustering can accurately differentiate patients with amnestic mild cognitive impairment (aMCI) from cognitively normal (CN) individuals. The second aim will be to determine the extent to which semantic processing might be associated with executive functions. Data from 202 (134 CN, 68 aMCI) participants were analyzed to quantify differences in semantic clustering ratios on the HVLT-R. Study participants ages ranged from 51 to 87 with education ranging from 6 to 20 years. ANCOVA revealed statistically significant differences on semantic clustering ratios (p < .001). Moderate correlations between semantic clustering Category Fluency Test (r = .45) were also found. Statistically significant group differences were also present on Trails-B and WAIS-R Digit Symbol performance (p < .001). Overall, these data indicate that deficits in semantic clustering are present in aMCI patients.     

Semantic memory verification of binary statements by children at three academic levels

Ninety-six binary statements were administered to 120 children randomly selected from three academic levels. The children were to respond TRUE or FALSE to each statement. Error count and latency for correct responses were used as measures of performance. The Constituent Comparison Model (Carpenter, P., & Just, M. A., Psychological Review, 1975, 82, 45–73), which postulates that verification latency will increase linearly with a linear increase in the number of hypothesized constituent comparisons, accounts quite well for the results obtained in this study. Furthermore, the results suggest an increasing efficiency in semantic memory verification across the three academic levels as reflected by a decrease in variability of performance, a decrease in the time required to read and encode sentences, and a decrease in the time required per constituent comparison.     

Mental models as representations of text

A theory of text representation is outlined which suggests that a text is encoded in a mental model that contains representations of only those individuals and events that are relevant to the interpretation of the text in question. Such models are constructed on-line in response to cues in the text and with reference to knowledge about the world. An experiment is reported which demonstrates that mental models represent the events most probably described in a text. The results confirm previous findings that memory for the content of a passage is not based on the construction of one of its linguistically motivated representations. However, unlike most previous findings, they do support a positive proposal about the nature of the representations on which memory for content is based.     

Parents' representations of their children: an exploratory study using the Osgood Semantic Differential Scales

The results of an exploratory national study carried out in Italy using Osgood's Semantic Differential Scales (Osgood, Suci, & Tannenbaum, 1957) with parents of 100 normal 6- to 11-yr.-old children in mainstream classrooms are reported. The aim was to devise a simple tool to be used to explore parents' perceptions of their children in this age group. Parents were asked to rate "my child" using some of Osgood's Semantic Differential Scales especially adapted for this study. Participants were 97 fathers and 100 mothers. Fathers were 32 to 57 years of age (M = 43.2, SD = 5.4), mothers were 29 to 49 years of age (M = 39.7, SD =4.4). In factor analysis four factors were identified: Activity, Evaluation, Emotions evoked by the child, Personality/Physical contact. Average factor scores were significantly different. There were no significant differences between fathers and mothers on the four factor scores. Children were more positively evaluated the younger they were.     

The CA3 network as a memory store for spatial representations

Comparative neuroanatomy suggests that the CA3 region of the mammalian hippocampus is directly homologous with the medio-dorsal pallium in birds and reptiles, with which it largely shares the basic organization of primitive cortex. Autoassociative memory models, which are generically applicable to cortical networks, then help assess how well CA3 may process information and what the crucial hurdles are that it may face. The analysis of such models points at spatial memories as posing a special challenge, both in terms of the attractor dynamics they can induce and how they may be established. Addressing such a challenge may have favored the evolution of elements of hippocampal organization observed only in mammals.     

Frequency-shift detectors bind binaural as well as monaural frequency representations

Previous psychophysical work provided evidence for the existence of automatic frequency-shift detectors (FSDs) that establish perceptual links between successive sounds. In this study, we investigated the characteristics of the FSDs with respect to the binaural system. Listeners were presented with sound sequences consisting of a chord of pure tones followed by a single test tone. Two tasks were performed. In the "present/absent" task, the test tone was either identical to one of the chord components or positioned halfway in frequency between two components, and listeners had to discriminate between these two possibilities. In the "up/down" task, the test tone was slightly different in frequency from one of the chord components and listeners had to identify the direction (up or down) of the corresponding shift. When the test tone was a pure tone presented monaurally, either to the same ear as the chord or to the opposite ear, listeners performed the up/down task better than the present/absent task. This paradoxical advantage for directional frequency shifts, providing evidence for FSDs, persisted when the test tone was replaced by a dichotic stimulus consisting of noise but evoking a pitch sensation as a consequence of binaural processing. Performance in the up/down task was similar for the dichotic stimulus and for a monaural narrow-band noise matched in pitch salience to it. Our results indicate that the FSDs are insensitive to sound localization mechanisms and operate on central frequency representations, at or above the level of convergence of the monaural auditory pathways.     

Semantic congruity and expectancy as separate processes

In two experiments, we investigated the role of expectancy in producing congruity effects in comparative judgment. In Experiment 1, instructions to choose the larger or smaller term either preceded pairs for comparative judgment or preceded individual words for lexical decision. If expectancy in interpreting the comparative judgment terms accounts for the congruity effect, the lexical decision task also should show a congruity effect. However, there were large congruity effects in comparative judgment but not in lexical decision. In this experiment, we used an infiniteset design to make sure that semantic information was needed on comparative judgment trials. In Experiment 2, comparative judgment pairs were preceded by a prime word that either was or was not a category label for the terms in the pairs. There were both congruity and priming effects, with no interaction between the two. This result implies that expectancy and the semanticcongruity effect come from separate processes.     

Semantic Determinants and Psychology as a Science

One central but unrecognized strand of the complex debate between W. V. Quine and Donald Davidson over the status of psychology as a science turns on their disagreement concerning the compatibility of strict psychophysical, semantic-determining laws with the possibility of error. That disagreement in turn underlies their opposing views on the location of semantic determinants: proximal (on bodily surfaces) or distal (in the external world). This paper articulates these two disputes, their wider context, and argues that both are fundamentally misconceived. There is no special tension between error and strict semantic-determining laws; moreover, the purported bearing of that issue on the dispute over the location of semantic determinants depends upon a mistaken conception of the relation between the nomic status of generalizations and degree of distance between explanans and it explananda. Finally, the wider significance of these conclusions for related contemporary debates is noted. And independent considerations about the possibility of communication, also present in Quine's and Davidson's thinking, are brought to bear on the question of the location of semantic determinants. This revised version was published online in August 2006 with corrections to the Cover Date.     

The dark side of Facebook: Semantic representations of status updates predict the Dark Triad of personality

Using Latent Semantic Analysis, we quantified the semantic representations of Facebook status updates of 304 individuals in order to predict self-reported personality. We focused on, besides Neuroticism and Extraversion, the Dark Triad of personality: Psychopathy, Narcissism, and Machiavellianism. The semantic content of Facebook updates predicted Psychopathy and Narcissism. These updates had a more “odd” and negatively valanced content. Furthermore, Neuroticism, number of Facebook friends, and frequency of status updates were predictable from the status updates. Given that Facebook allows individuals to have major control in how they present themselves and draw benefits from these interactions, we conclude that the Dark Triad, involving socially malevolent behavior such as self-promotion, emotional coldness, duplicity, and aggressiveness, is manifested in Facebook status updates.     

Younger and older adults' use of mental models as representations for text materials

Recent work suggests that formation and use of mental model (representations of situations described) is an integral part of discourse comprehension. In an experiment comparing younger and older adults on this aspect of text comprehension, subjects heard readings of a list of sentences and took a forced-choice recognition test. The test contained 2 types of distractors with an equal degree of verbatim similarity to the target sentences. One type described the same situation as the corresponding target sentence; the other did not. If mental models are an integral part of text representation formed at encoding, then a large number of confusions of the first, but not the second, type of distractor with the target sentence would be obtained. Younger and older adults showed this pattern to equal degrees. These data are consistent with those indicating that linguistic competence remains stable over the adult years (cf. Light, 1988).     

Text representations as reflected in patterns of cognitive distance

Subjects performed a task that involved learning a text and then indicating, for each of a series of pairs of words, whether they belonged to the same sentence of that text. When the principle of argument overlap or causal coherence was the sole integrative factor in a text, negative response times and error rates reflected distances in the network representation predicted by the principle. When the two principles predicted conflicting representations for a text, response times and error rates reflected the predictions of the principle of argument overlap. The results were interpreted as suggesting that network connections predicted by the two principles are both present in the memory representations of texts and that causal connections are recorded at a more abstract level of representation than are argument overlap connections.