A decidable multi-modal logic of context

We give a logic for formulas φ−ψ, with the informal reading “ψ is true in the context described by φ”. These are interpreted as binary modalities, by quantification over an enumerable set of unary modalities c−ψ, meaning “ψ is true in context c”. The logic allows arbitrary nesting of contexts.A corresponding axiomatic presentation is given, and proven to be decidable, sound, and complete.Previously, quantificational logic of context restricted the nesting of contexts, and was only known to be decidable in very special cases.     

Reaction times and dyslexia

Five groups of children, including two groups of dyslexics (aged 15 and 11 years), were tested on simple reaction, selective choice reaction, and lexical decision tasks. In simple reactions to a pure tone, the dyslexic children responded as quickly as their chronological age controls and significantly faster than their reading age controls. In selective choice reactions to pure tones, the dyslexic children were significantly impaired compared with their chronological age controls and no faster than their reading age controls. This speed impairment obtained even though a selective choice reaction task has only one positive response. In “by-item” analyses of lexical decisions to spoken words, the dyslexic children were significantly impaired compared even with their reading age controls. The pattern of results suggests that at least two factors contribute to slowness of dyslexic children: a general deficit reflected in slower stimulus classification speed and a linguistic deficit reflected in slower lexical access speed.     

Picture Naming Deficits in Developmental Dyslexia: The Phonological Representations Hypothesis

The picture and word naming performance of developmental dyslexics was compared to the picture and word naming performance of non-dyslexic (“garden variety”) poor readers, reading age, and chronological age-matched controls. The stimulus list used for both tasks was systematically manipulated for word length and word frequency. In order to examine picture naming errors in more depth, an object name recognition test assessed each subject's vocabulary knowledge of those names which they were unable to spontaneously label in the picture naming task. Findings indicated that the dyslexic and the garden variety poor readers exhibited a picture naming deficit relative to both chronological and reading age-matched controls. Findings also indicated that both groups of impaired readers obtained superior scores in the word naming task than in the picture naming task, while both groups of controls showed no difference in performance across tasks. The dyslexics' picture naming errors, but not those of the garden variety poor readers, were particularly marked on polysyllabic and/or low frequency words, indicating a possible phonological basis to the picture naming deficit of the dyslexic children. These children also recognized significantly more unnamed target words than all comparison groups, suggesting a particular difficulty inretrievingthe phonological codes of known picture names rather than a vocabulary deficit. Results are discussed in terms of dyslexics' difficulty in encoding full segmental phonological representations of names in long-term memory and/or in processing these representations in order to generate required names on demand.     

Developmental and acquired dyslexia: A comparison

Jorm (1979a) has drawn attention to similarities between developmental dyslexia and acquired deep dyslexia, an analogy which has been criticized by A. W. Ellis (1979). A series of three experiments compared the two syndromes, using the techniques applied by Patterson and Marcel (1977) to adult deep dyslexics, to study a group of 15 boys suffering from developmental dyslexia. Patterson and Marcel's patients were able to perform a lexical decision task but showed no evidence of phonemic encoding of nonwords; our dyslexic children performed this task very slowly and with reduced accuracy but showed clear evidence of phonemic coding of the nonword items. Patterson and Marcel observed that their patients could not read out orthographically regular nonwords; our dyslexic children were able to do this task, although more slowly and somewhat less accurately than their chronological age or reading age controls. Finally, Patterson and Marcel observed that highly imageable words were more likely to be read correctly than words of equal frequency but low imageability; we observed a similar effect in both our dyslexic group and in their reading age controls. This implies that the imageability effect may not be peculiar to dyslexics but may be characteristic of normal reading under certain conditions. It is concluded that developmental dyslexics differ from the patients studied by Patterson and Marcel in demonstrating a pattern of reading which, though slow, is qualitatively similar to the reading of normal readers of a younger age. As such, our results do not support Jorm's position.     

Impaired processing of rapid stimulus sequences in dyslexia

Apart from their reading difficulties, dyslexic subjects often suffer from a variety of subtle sensory and motor deficits. Whether these deficits have a causal relationship to the reading disorder, form additional risk factors, or are totally independent of the reading problem, is under vivid debate. In this article, we review the evidence and suggest that ‘sluggish attentional shifting’ (SAS) can account for the impaired processing of rapid stimulus sequences in dyslexia. Within this novel framework attention-related prolongation of input chunks is decisive for many small deficits found in dyslexic subjects.     

Right hemisphere contribution to lexical access in an aphasic with deep dyslexia

Three hemifield tachistoscopic studies of a right-handed patient with acquired Broca's aphasia and deep dyslexia, but with intact visual fields, are presented to support the hypothesis of right hemisphere (RH) participation in deep dyslexic reading. A systematic comparison of this deep dyslexic with the disconnected RHs of two patients with complete cerebral commissurotomy disclosed a similar, but not identical, pattern of abilities. The results demonstrate partial reliance on the RH for accessing the meaning of single words, but not for phonological encoding in this patient.     

The nature of phonological processing in oral reading: Evidence from surface dyslexia

Investigation of a neurological patient (PT) who presents with a relatively pure disorder of reading was carried out. His performance on a number of oral reading tasks was very similar to that of the surface dyslexic patient (HTR) reported by Shallice, Warrington and McCarthy (1983). Both patients showed an effect of “degree” of regularity in terms of accuracy of reading response. PT did not, however, show an effect of “typicality of divergence”, which was considered by Shallice and his colleagues to be responsible for the former effect. The size of orthographic-phonological unit operational in PT's oral reading was experimentally determined. PT appeared to rely on grapheme-phoneme correspondences that were assigned in a probabilistic rather than an “all-or-none” manner. No evidence for the existence of the sub-syllable as an independent unit was found. In contrast, this unit apparently mediated the performance of skilled adult readers. Implications of these results for models of the phonological route are discussed.     

Theory of mind for learning and teaching: the nature and role of explanation

The relationship between “theory of mind” and teaching is deep and complex. We focus on one particularly powerful link that is based on the role of children's psychological explanations in their learning. Psychological explanations involve explaining persons’ actions and lives as the causes and consequences of their mental states. We begin by showing that psychological explanations are central to children's developing theories of mind—they are part of the mechanism for development in this domain. We then review theory and data suggesting that psychological explanations are also critically important for learning and being taught more generally.     

Dyslexia,authorial identity,and approaches to learning and writing: A mixed methods study

Background. Dyslexia may lead to difficulties with academic writing as well as reading. The authorial identity approach aims to help students improve their academic writing and avoid unintentional plagiarism, and could help to understand dyslexic students’ approaches to writing. Aims. (1) To compare dyslexic and non‐dyslexic students’ authorial identity and approaches to learning and writing; (2) to compare correlations between approaches to writing and approaches to learning among dyslexic and non‐dyslexic students; (3) to explore dyslexic students’ understandings of authorship and beliefs about dyslexia, writing and plagiarism. Sample. Dyslexic (n= 31) and non‐dyslexic (n= 31) university students. Method. Questionnaire measures of self‐rated confidence in writing, understanding of authorship, knowledge to avoid plagiarism, and top‐down, bottom‐up and pragmatic approaches to writing (Student Authorship Questionnaire; SAQ), and deep, surface and strategic approaches to learning (Approaches and Study Skills Inventory for Students; ASSIST), plus qualitative interviews with dyslexic students with high and low SAQ scores. Results. Dyslexic students scored lower for confidence in writing, understanding authorship, and strategic approaches to learning, and higher for surface approaches to learning. Correlations among SAQ and ASSIST scores were larger and more frequently significant among non‐dyslexic students. Self‐rated knowledge to avoid plagiarism was associated with a top‐down approach to writing among dyslexic students and with a bottom‐up approach to writing among non‐dyslexic students. All the dyslexic students interviewed described how dyslexia made writing more difficult and reduced their confidence in academic writing, but they had varying views about whether dyslexia increased the risk of plagiarism. Conclusions. Dyslexic students have less strong authorial identities, and less congruent approaches to learning and writing. Knowledge to avoid plagiarism may be more salient for dyslexic students, who may benefit from specific interventions to increase confidence in writing and understanding of authorship. Further research could investigate how dyslexic students develop approaches to academic writing, and how that could be affected by perceived knowledge to avoid plagiarism.     

Word form access dyslexia: understanding the basis of visual reading errors

We report the case of a patient V.E.M. who exhibits the infrequently described syndrome of visual dyslexia. V.E.M. read many single words accurately and rapidly; however, when words were read inaccurately, the majority of responses were alternate real words bearing a strong visual relationship to the target items. A series of observational and experimental investigations of her reading skills revealed that response accuracy was strongly affected by word frequency and mildly affected by concreteness but not influenced by word length, orthographic neighbourhood size, or semantic priming. It is argued that V.E.M.'s visual dyslexia results from a deficit of the visual word form system. More specifically, we propose that this deficit has an “access” quality, with visual word form representations remaining relatively intact despite an impairment in the processes by which these representations are activated. Taking the results of this study together with previous reports of dyslexic patients who make a high proportion of visual paralexic errors, we also suggest that visual dyslexia represents a multicomponent dyslexic syndrome for which phonological impairment and not semantic impairment may be a necessary condition.     

Reading without phonology: Evidence from aphasia

This study of an aphasic dyslexic supports the view that there are separate visual and phonological pathways in reading. The patient retained a reading vocabulary of at least 16 500 words although she was unable to perform operations that critically depend on grapheme-to-phoneme conversion; these included reading nonsense words, recognizing rhymes and homophones, and accessing lexical entries from homophonic spellings such as “kote”. Typographical variation, such as mixed case presentation, did not interfere with her reading performance, which suggests that it is mediated by letter identification rather than by a wholistic method of word recognition. The total performance pattern strongly suggests that this patient identifies words by matching particular letter-strings with their corresponding meanings.     

Automatic Activation of Word Phonology from Print in Deep Dyslexia

The performance of deep dyslexics in oral reading and other tasks suggests that they are poor at activating the phonology of words and non-words from printed stimuli. As the tasks ordinarily used to test deep dyslexics require controlled processing, it is possible that the phonology of printed words can be better activated on an automatic basis. This study investigated this possibility by testing a deep dyslexic patient on a lexical decision task with pairs of stimuli presented simultaneously. In Experiment 1, which used content words as stimuli, the deep dyslexic, like normal subjects, showed faster reaction times on trials with rhyming, similarly spelled stimuli (e.g. bribe-tribe) than on control trials (consisting of non-rhyming, dissimilarly spelled words), but slower reaction times on trials with non-rhyming, similarly spelled stimuli (e.g. couch-touch). When the experiment was repeated using function words as stimuli, the patient no longer showed a phonological effect. Therefore, the phonological activation of printed content words by deep dyslexics may be better than would be expected on the basis of their oral reading performance.     

Locus of control and the perception of freedom in an agent of reinforcement

Internals and externals observed a staged videotape presentation that portrayed a “teacher” and a “learner” engaging in a 20-item anagrams task. For externals, any variability (10, 50, and 90% schedule) in the reinforcing behavior of the “teacher” (agent of reinforcement) resulted in significantly greater perceived freedom than when no variability (0 and 100% schedule) occurred in behavior. For internals, perceived freedom was a negative linear function of the amount of reinforcement administered. Internals indicated that they could influence the behavior of the “teacher” in all reinforcement conditions, whereas externals indicated that they could influence only the “teachers” in the variable reinforcement conditions. It was concluded that greater freedom is attributed to a person whose behavior is perceived as congruent with the person's inner disposition.     

New evidence for morphological errors in deep dyslexia

Morphological errors in reading aloud (e.g., sexist-->sexy) are a central feature of the symptom-complex known as deep dyslexia, and have historically been viewed as evidence that representations at some level of the reading system are morphologically structured. However, it has been proposed (Funnell, 1987) that morphological errors in deep dyslexia are not morphological in nature but are actually a type of visual error that arises when a target word that cannot be read aloud (by virtue of its low imageability and/or frequency) is modified to form a visually similar word that can be read aloud (by virtue of its higher imageability and/or frequency). In the work reported here, the deep dyslexic patient DE read aloud lists of genuinely suffixed words (e.g., killer), pseudosuffixed words (e.g., corner), and words with non-morphological embeddings (e.g., cornea). Results revealed that the morphological status of a word had a significant influence on the production of stem errors (i.e., errors that include the stem or pseudostem of the target): genuinely suffixed words yielded more stem errors than pseudosuffixed words or words with non-morphological embeddings. This effect of morphological status could not be attributed to the relative levels of target and stem imageability and/or frequency. We argue that this pattern of data indicates that apparent morphological errors in deep dyslexic reading are genuinely morphological, and discuss the implications of these errors for theories of deep dyslexia.     

Speed of lower-level auditory and visual processing as a basic factor in dyslexia: electrophysiological evidence

This study investigated speed of processing (SOP) among college-level adult dyslexic and normal readers in nonlinguistic and sublexical linguistic auditory and visual oddball tasks, and a nonlinguistic cross-modal choice reaction task. Behavioral and electrophysiological (ERP) measures were obtained. The results revealed that between both groups, reaction times (RT) were longer and the latencies of P2 and P3 components occurred later in the visual as compared to auditory oddball tasks. RT and ERP latencies were longest in the cross-modal task. RT and ERP latencies were delayed among dyslexic as compared to normal readers across tasks. On the oddball tasks, group differences in brain activity were observed only when responding to low-probability targets. These differences were largest for the P3 component, and most pronounced in the case of phonemes. The gap between ERP latencies in the visual versus the auditory modalities for each component was larger among dyslexic as compared to normal readers, and was particularly evident at the linguistic level. A hypothesis is proposed that suggests an amodal, basic SOP deficit among dyslexic readers. The slower cross-modal SOP is attributed to slower information processing in general and to disproportionate "asynchrony" between SOP in the visual versus the auditory system. It is suggested that excessive asynchrony in the SOP of the two systems may be one of the underlying causes of dyslexics' impaired reading skills.     

Voice onset time production and perception in apraxic subjects

This study explored the relationship between the perception and production of voice onset time (VOT) in apraxic subjects. Spectrograms of the words, “bees” and “peas” spoken by apraxic subjects were acoustically analyzed to obtain a measure of VOT. The subjects also identified the initial cognate (“b” or “p”) from synthetically generated speech spanning a voiced to voiceless time continuum. The results suggest that apraxic subjects have production as well as perceptual errors in the voicing feature but no significant relationship was found between the two measures.     

Point of view in personal memories

A structural aspect of personal memories was examined in four studies. In some memories, one has the perspective of an observer, seeing oneself “from the outside.” In other memories, one sees the scene from one's own perspective; the field of view in such memories corresponds to that of the original situation. The existence of “observer” and “field” memories was confirmed in Study 1, using a recall questionnaire. In Study 2, the similarity structure of a specified set of eight to-be-recalled situations was established: the significant dimensions were “emotionality” and “self-awareness.” Study 3 related these dimensions to the observer-field distinction; situations involving a high degree of emotion and selfawareness were most likely to be recalled with an observer perspective. Recall set was varied in Study 4: a focus on feelings (as opposed to objective circumstances) produced relatively more field memories. Studies 3 and 4 also showed that events reported as more recent tend to be recalled in the field mode. Thus a qualitative characteristic of personal memories—the perspective from which they are experienced—is apparently related to characteristics of the original event, to the individual's purpose in recalling that event, and to the reported recall interval.     

Crossmodal integration in the identification of consonant segments

Although speechreading can be facilitated by auditory or tactile supplements, the process that integrates cues across modalities is not well understood. This paper describes two “optimal processing” models for the types of integration that can be used in speechreading consonant segments and compares their predictions with those of the Fuzzy Logical Model of Perception (FLMP, Massaro, 1987). In “pre-labelling” integration, continuous sensory data is combined across modalities before response labels are assigned. In “post-labelling” integration, the responses that would be made under unimodal conditions are combined, and a joint response is derived from the pair. To describe pre-labelling integration, confusion matrices are characterized by a multidimensional decision model that allows performance to be described by a subject's sensitivity and bias in using continuous-valued cues. The cue space is characterized by the locations of stimulus and response centres. The distance between a pair of stimulus centres determines how well two stimuli can be distinguished in a given experiment. In the multimodal case, the cue space is assumed to be the product space of the cue spaces corresponding to the stimulation modes. Measurements of multimodal accuracy in five modern studies of consonant identification are more consistent with the predictions of the pre-labelling integration model than the FLMP or the post-labelling model.     

The “sexually abused child”: Potential mechanisms of adverse influences of such a label

Labeling and the effects of labeling have been extensively researched in the psychological literature in a variety of different contexts. For example, labeling has been empirically shown to lead to lowered expectancies of behavior and achievement, which can then contribute to the potential for the occurrence of a self-fulfilling prophecy with adverse consequences. Another area that has been extensively researched, with a dramatic increase in the literature base in recent history, is that of child sexual abuse (CSA). Despite various shortcomings of the research literature, the consistent findings have been identification of a variety of negative correlates and symptomatologies associated with CSA. In addition to any direct, negative effects of CSA, there may also be an additional impact from the “label” itself. Although the literature pertaining to CSA and labeling runs deep independently, efforts at addressing the issue of CSA within a labeling contextual framework have been minimal. To that end, this article examines hypothesized mechanisms of how the “sexual abuse” label may potentially have an adverse influence on the children subjected to such a label. The implications of an analysis, which addresses childhood sexual abuse from such a theoretical framework, may be a broader and more holistic understanding of the complexities and sequelae associated with CSA.