Famous people knowledge and the right and left temporal lobes

It is generally accepted that the anterior temporal lobes support knowledge of famous people. The specific roles of the right and left temporal lobe remain a subject of debate, with some studies suggesting differential roles based on modality (visual versus verbal information) and others category (person knowledge versus general semantics). The present study re-examined performance of semantic dementia patients with predominantly right and predominantly left temporal lobe atrophy on famous face, famous name and general semantic tasks, with the specific aim of testing the hypothesis that the right temporal lobe has a privileged role for person knowledge and the left temporal lobe for general semantic knowledge. Comparisons of performance rankings across tasks showed no evidence to support this hypothesis. By contrast, there was robust evidence from naming, identification and familiarity measures for modality effects: right-sided atrophy being associated with relatively greater impairment for faces and visual tasks and left-sided atrophy for names and verbal tasks. A double dissociation in test scores in two patients reinforced these findings. The data present a challenge for the influential `semantic hub' model, which views the anterior temporal lobes as an area of convergence in which semantic information is represented in amodal form.     

Preservation of categorical knowledge in Alzheimer's disease: A computational account

Abstract

The distinction between knowledge of specific exemplars and knowledge of their general categories is central to much theorising on the nature of semantic memory. The dissociation between exemplar and category knowledge observed in Alzheimer's Disease (AD) would appear to support this distinction, and to suggest that different neural systems are involved in the representation of exemplar and category knowledge. We review the evidence for preserved category knowledge in the semantic memory impairment of AD, and propose an alternative interpretation, according to which category and exemplar knowledge are both represented in the same distributed neural substrate. The relative preservation of category knowledge is a consequence of the greater frequency, and hence greater robustness, of the representation of attributes shared by all or most members of a category, compared to exemplar-unique attributes. We test and confirm the computational adequacy of this hypothesis in two computer simulations.     

The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

Semantic cognition, as described by the controlled semantic cognition (CSC) framework (Rogers et al., 2015 , Neuropsychologia, 76, 220), involves two key components: activation of coherent, generalizable concepts within a heteromodal ‘hub’ in combination with modality‐specific features (spokes), and a constraining mechanism that manipulates and gates this knowledge to generate time‐ and task‐appropriate behaviour. Executive–semantic goal representations, largely supported by executive regions such as frontal and parietal cortex, are thought to allow the generation of non‐dominant aspects of knowledge when these are appropriate for the task or context. Semantic aphasia (SA) patients have executive–semantic deficits, and these are correlated with general executive impairment. If the CSC proposal is correct, patients with executive impairment should not only exhibit impaired semantic cognition, but should also show characteristics that align with those observed in SA. This possibility remains largely untested, as patients selected on the basis that they show executive impairment (i.e., with ‘dysexecutive syndrome’) have not been extensively tested on tasks tapping semantic control and have not been previously compared with SA cases. We explored conceptual processing in 12 patients showing symptoms consistent with dysexecutive syndrome (DYS) and 24 SA patients, using a range of multimodal semantic assessments which manipulated control demands. Patients with executive impairments, despite not being selected to show semantic impairments, nevertheless showed parallel patterns to SA cases. They showed strong effects of distractor strength, cues and miscues, and probe–target distance, plus minimal effects of word frequency on comprehension (unlike semantic dementia patients with degradation of conceptual knowledge). This supports a component process account of semantic cognition in which retrieval is shaped by control processes, and confirms that deficits in SA patients reflect difficulty controlling semantic retrieval.     

Knowing Other People: A Second‐Person Framework

What does it mean to know another person, and how is such knowledge different from other kinds of knowledge? These questions constitute an important part of what I call ‘second‐person epistemology’ – the study of how we know other people. I claim that knowledge of other people is not only central to our everyday lives, but it is a kind of knowledge that is unlike other kinds of knowledge. In general, I will argue that second‐person knowledge arises from repeated interactions with another person, and that it also requires employment of certain cognitive abilities and a unique kind of second‐order knowledge. This paper provides the framework for a second‐person epistemology by examining some of our ordinary claims about what it means to know another person. I describe four conditions that typically characterize knowing another person. Then I describe the psychological grounds of knowing a person. Finally, I conclude with some thoughts about the unique symmetries of second person knowledge and the role of such knowledge in our broader epistemological endeavours.     

Implications of measures of reliability for theories of priming: Activity in semantic memory is inherently noisy and uncoordinated

In experiments on semantic priming, participants vary substantially in the absolute magnitude of priming they produce. Are these individual differences systematic or do they arise from random processes, and does the answer carry theoretical implications? To find out, we examined split‐half and test–retest reliability of semantic priming in a series of two‐session experiments that crossed relatedness proportion (RP, at .25, .50, and .75) with stimulus–onset asynchrony (SOA, at 200, 350, and 800 ms). Low reliability would indicate little coherence of activity within semantic memory, so that the degree to which any given association influences performance is uncorrelated from one association and time of testing to the next. High reliability would indicate that each person tends to harness his or her semantic knowledge consistently, applying semantic relations among words in much the same way from one word to the next and one time of testing to the next to help task performance, resulting in systematic individual differences. What we observed was low reliability—often zero. When conditions highlighted “automatic activation” (low RP, short SOA), priming was completely uncorrelated from item to item and session to session. Both split‐half and test–retest reliability increased to significant levels under conditions that raised the probability that an activated or retrieved episode of prime experience would help with target recognition, and the probability of intentionally generating the target from the prime. Thus, task‐relevant" utility imposes a modicum of order on semantic associations that are otherwise noisy and uncoordinated. Harnessing semantic memory is like herding cats—without considerable constraint, associations tend to come and go their own ways in independent fashion.     

Naïve Realism,Privileged Access,and Epistemic Safety

Working from a naïve‐realist perspective, I examine first‐person knowledge of one's perceptual experience. I outline a naive‐realist theory of how subjects acquire knowledge of the nature of their experiences, and I argue that naive realism is compatible with moderate, substantial forms of first‐person privileged access. A more general moral of my paper is that treating “success” states like seeing as genuine mental states does not break up the dynamics that many philosophers expect from the phenomenon of knowledge of the mind.     

Semantic memory disorders

Semantic memory encompasses knowledge of objects, facts and words. A number of brain regions are probably involved, but the left infero-lateral temporal lobe appears to play a key role. The separability of semantic memory from episodic (or autobiographical) memory is a focus of current debate. Impaired semantic memory is a common feature of Alzheimer's disease but is invariably overshadowed by a profound deficit in episodic memory. In semantic dementia, a rarer disorder associated with focal temporal-lobe atrophy, there is selective loss of semantic memory, characterized by preservation of superordinate knowledge of words, and objects, but loss of finer-grained information. This pattern can be interpreted as a degradation of features from a distributed network of semantic representations. Following Herpes simplex encephalitis, patients sometimes show disproportionate loss of knowledge for natural kinds (e.g. animals) with relative preservation of knowledge about artefacts, this may reflect differential damage to neural systems critical for perceptual as opposed to functional features, perceptual properties being more salient in knowledge about natural kinds.     

Altering access to autobiographical episodes with prior semantic knowledge

Within autobiographical knowledge, semantic and episodic memory are traditionally considered separate, but newer models place them along a continuum, which raises the possibility of an intermediate form of knowledge - personal semantics. This study tested how different types of semantics – general semantics and two forms of personal semantics – impact access to personal episodic memories. In two experiments, participants made a series of true/false judgments about a prime statement, which reflected a general semantic fact, a context-dependent (e.g., repeated event) or context-independent (e.g., trait), personal semantic fact and then retrieved a specific past episodic memory. There was a significantly stronger priming effect for accessing specific episodic memories after judging personal semantic facts versus general facts. We also found that context-dependent and -independent personal semantic facts had separable priming effects on episodic memory. These findings support a continuum model of memory and verifies that there are multiple forms of personal knowledge.     

Conceptual structure and the structure of concepts: a distributed account of category-specific deficits

We present a new account of the fine-grained structure of semantic categories derived from neuropsychological, behavioral, and developmental data. The account places theoretical emphasis on the functions of the referents of concepts. We claim (i) that the distinctiveness of functional features correlated with perceptual features varies across semantic domains; and (ii) that category structure emerges from the complex interaction of these variables. The representational assumptions that follow from these claims make strong predictions about what types of semantic information are preserved in patients showing category-specific deficits following brain damage. These claims are illustrated with a connectionist simulation which, when damaged, shows patterns of preservation of distinctive and shared functional and perceptual information which varies across semantic domains. The data model both dissociations between knowledge for artifacts and for living things and recent neuropsychological evidence concerning the robustness of functional information in the representation of concepts.     

Cognitive skills in mathematical problem solving in Grade 3

Background. Research on the relationship between cognitive skills and mathematical problem solving is usually conducted on adults or on participants with acquired deficits associated with brain injury (e.g. Cipolotti, 1995 ; Cohen, Dehaene, & Verstichel, 1994 ; McCloskey, 1992 ). Aims. In these studies we wanted to make a contribution to the field of children's mathematical problem solving. The first aim of this study was to investigate whether mathematical problem solving in children is merely determined by semantic elaboration, as hypothesized in some of the models of adult processing (semantic hypothesis). In addition, we aimed to investigate whether there is a continuum from very good to very poor mathematical problem solving among children with mathematical learning disabilities showing immature cognitive skills (maturational lag hypothesis). Sample. The participants were 376 third graders and 107 second graders. Method. The internal structure of the data was analysed with a principal components analysis. In addition, two MANOVA were conducted to compare children with learning disabilities or problems with age‐matched and performance‐matched subjects. Results. Two components, a semantic and a non‐semantic one, were needed to account for an adequate fit of the dataset. In addition, children with mathematical learning disabilities had less‐developed cognitive skills compared with peers without learning disabilities, but they did not differ from younger children on seven of the nine cognitive skills. Conclusions. This study highlighted that children's mathematical problem solving is not determined by one general component. The picture is more complex, since two mathematics components were found. In addition, although our findings point in the direction of the maturational lag hypothesis it may be important to assess the different cognitive skills and especially assess the number system knowledge, since it seems below average in children with mathematical learning disabilities, compared with the knowledge of younger children with comparable skills in mathematics.     

Receptive vocabulary and semantic knowledge in children with SLI and children with Down syndrome

Receptive vocabulary and associated semantic knowledge were compared within and between groups of children with specific language impairment (SLI), children with Down syndrome (DS), and typically developing children. To overcome the potential confounding effects of speech or language difficulties on verbal tests of semantic knowledge, a novel task was devised based on picture-based semantic association tests used to assess adult patients with semantic dementia. Receptive vocabulary, measured by word-picture matching, of children with SLI was weak relative to chronological age and to nonverbal mental age but their semantic knowledge, probed across the same lexical items, did not differ significantly from that of vocabulary-matched typically developing children. By contrast, although receptive vocabulary of children with DS was a relative strength compared to nonverbal cognitive abilities (p < .0001), DS was associated with a significant deficit in semantic knowledge (p < .0001) indicative of dissociation between word-picture matching vocabulary and depth of semantic knowledge. Overall, these data challenge the integrity of semantic-conceptual development in DS and imply that contemporary theories of semantic cognition should also seek to incorporate evidence from atypical conceptual development.     

Normative beliefs supporting aggression of Arab children in an intergroup conflict

Based on the social knowledge theory (Heusmann), this study investigated normative beliefs supporting aggression (NOBAG), empathy, and intergroup anxiety of Arab children in Israel. The study proposed that ethnicity of the target person (within subject variable) and participant's sex (between subject variable) will differ between respondents' level of NOBAG and empathy: Higher NOBAG and lower empathy toward an outgroup member were expected. Sex differences were expected on all variables, as well as intercorrelations among them. Measures included the Revised Normative Beliefs Measure (NOBAG: general and specific), The Index of Empathy for Children and Adolescents (general and specific), and the Intergroup Anxiety Scale. The study population included 186 elementary‐school children from two Arab schools in Israel. Results indicated that all participants support an aggressive reaction to a child of an outgroup more than to one of their own group and exhibit a greater degree of empathy toward the latter. Sex differences were found on all variables except on specific NOBAG. Correlation coefficients suggest sex differences in relations between variables. Results of a Logistic regression for the prediction of NOBAG toward ingroup/outgroup person indicated that empathy toward Jews predicted NOBAG in both sexes while intergroup anxiety predicted NOBAG in a different way for boys and girls. The discussion refers to the need for peace education to reduce anxiety and promote empathy. Aggr. Behav. 00:000–000, 2005. © 2005 Wiley‐Liss, Inc.     

Ecological and person‐oriented aspects of metacognitive processes in test‐taking

This study examines critical aspects of both the ecological and the person‐oriented accounts of observed biases in confidence judgements on tests of cognitive abilities. These biases reflect metacognitive processes involved in test‐taking. According to the ecological approach, poor realism of confidence judgements is due to the nature of the items included in general knowledge tests (test‐driven biases). The person‐oriented approach, however, argues that biases in confidence judgements may be due to a general self‐monitoring trait. The present study employed the ‘de‐biasing’ procedure proposed by Juslin ( 1994 ) for the selection of general knowledge test items, and used a newly developed geographical knowledge test suitable for the Australian population. Two other cognitive tests (Raven's Progressive Matrices and Line Length) were administered in order to determine whether there is a consistency in confidence ratings across diverse tasks. Statistical procedures traditional to both approaches‐calibration curves and factor analysis ‐ were employed. The results, with minor qualifications, support both perspectives. The study found a separate confidence factor, indicative of a self‐monitoring trait. Two other potential metacognitive factors (i.e. ‘expectation’ and ‘evaluation’, corresponding to self‐assessment/planning and self‐evaluation) could not be separated from accuracy and speed measures. Copyright © 2001 John Wiley & Sons, Ltd.     

Instantiation of general terms in young and older adults

Instantiation of general terms in discourse requires inference from general world knowledge and use of linguistic context to particularize meaning. According to the semantic deficit hypothesis, older adults should be less likely than young adults to generate or to store such inferences. In Experiments 1 and 2 an indirect measure, relatedness judgment, was used to assess immediate comprehension and memory for inferences. In Experiment 3 a direct measure, cued recall, was used to tap memory for inferences. No age differences in immediate or delayed memory were observed in Experiments 1 or 2. In Experiment 3 older adults recalled fewer sentences, but there was no evidence for a specific decrement in storage of inferential material. Older adults are not impaired in ability to draw inferences based on general world knowledge, nor are they more likely than young adults to encode linguistic information in a general, stereotypic fashion.     

A case study investigating the role of the anterior temporal lobes in general semantics and semantics specific to persons,emotions and social conceptual knowledge

The role of the anterior temporal lobes (ATLs) in semantic representation remains still much debated. Long thought to support domain-general semantic processing, recent accounts have alternatively suggested that they may be preferentially involved in the processing of person-related semantic knowledge. Several studies have supported such a distinction, but few have either examined both types of semantic processing together, or considered the role of potentially important confounding variables. Here, we address these issues by investigating both domain-general and person-specific semantic processing in a patient with focal ATL damage. The patient presents with dense anterograde and retrograde amnesia. Performance was impaired on tests of general semantic knowledge, but most striking deficits were for person-related semantics, including recognition and identification, knowledge of emotions and social conceptual knowledge. This unique case provides compelling evidence that, in addition to the role in general semantic knowledge, the ATLs are critical for person-related semantics.     

Knowing about People and Naming Them: Can Alzheimer's Disease Patients Do One without the Other?

It has recently been suggested that patients with semantic breakdown may show the phenomenon of so-called 'naming without semantics'. If substantiated, this finding would clearly have a major impact on theories of face and object processing, all of which assume that access to semantic knowledge is a prerequisite for successful naming. In order to investigate this issue, we studied recognition, identification (the ability to provide accurate information), and naming of 50 famous faces by 24 patients with mild to moderate dementia of Alzheimer type (DA T) and 30 age-matched controls. The DA T group was impaired in all three conditions. An analysis of the concordance between identification and naming by each patient, for each stimulus item, established that naming a famous face was possible only with semantic knowledge sufficient to identify the person. Our data support the hypothesis that naming is not possible unless semantic information associated with the target is available. Naming without semantics, therefore, did not occur in patients with DAT. By contrast, there were 206 instances (17% of the total responses) in which the patients were able to provide detailed, accurate identifying information yet were unable to name the person represented. The implication of these findings for models of face identification and naming are discussed.     

Dissociations of language function in dementia: A case study

In this report we describe and attempt to characterize the deterioration in semantic knowledge occurring in a victim of a progressive dementing disease. The subject was unable to match even highly familiar naming words with their actual or pictured referents; instead, she consistently overextended verbal labels to closely associated distractors. The alteration in scope of referential meanings suggested by this overextension effect was apparently related to a breakdown in the structure of underlying categories. On a nonverbal match-to-sample procedure, for example, dogs were treated as exemplars of the cat family. Evidence for the breakdown of semantic knowledge was not limited to picture labeling paradigms. Thus, we found that the subject was unable to utilize semantic context in the written disambiguation of spoken homophones but could, at the same time, use even minimal syntactic cues as the basis for proper lexical selection. This last result was consistent with other lines of evidence pointing to the relative preservation of syntactic operations, in marked contrast to the semantic loss. The importance of this dissociation of function in organic pathology is considered from a number of perspectives, including its relevance to models of language organization in the brain.     

SD-squared: on the association between semantic dementia and surface dyslexia

Within the connectionist triangle model of reading aloud, interaction between semantic and phonological representations occurs for all words but is particularly important for correct pronunciation of lower frequency exception words. This framework therefore predicts that (a) semantic dementia, which compromises semantic knowledge, should be accompanied by surface dyslexia, a frequency-modulated deficit in exception word reading, and (b) there should be a significant relationship between the severity of semantic degradation and the severity of surface dyslexia. The authors evaluated these claims with reference to 100 observations of reading data from 51 cases of semantic dementia. Surface dyslexia was rampant, and a simple composite semantic measure accounted for half of the variance in low-frequency exception word reading. Although in 3 cases initial testing revealed a moderate semantic impairment but normal exception word reading, all of these became surface dyslexic as their semantic knowledge deteriorated further. The connectionist account attributes such cases to premorbid individual variation in semantic reliance for accurate exception word reading. These results provide a striking demonstration of the association between semantic dementia and surface dyslexia, a phenomenon that the authors have dubbed SD-squared.     

Relative category-specific preservation in semantic dementia? Evidence from 35 cases

Category-specific deficits have rarely been reported in semantic dementia (SD). To our knowledge, only four previous studies have documented category-specific deficits, and these have focused on the living versus non-living things contrast rather than on more fine-grained semantic categories. This study aimed to determine whether a category-specific effect could be highlighted by a semantic sorting task administered to 35 SD patients once at baseline and again after 2 years and to 10 Alzheimer’s disease patients (AD). We found a relative preservation of fruit and vegetables only in SD.This relative preservation of fruit and vegetables could be considered with regard to the importance of color knowledge in their discrimination. Indeed, color knowledge retrieval is known to depend on the left posterior fusiform gyrus which is relatively spared in SD. Finally, according to predictions of semantic memory models, our findings best fitted the Devlin and Gonnerman’s computational account.