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Max Coltheart

Publications and source records attributed to Max Coltheart.

33 records · Page 2Linked to original sources
PubMed2004

Recognition of metaphor and irony in young adults: the impact of schizotypal personality traits.

Patients with schizophrenia demonstrate two dissociable impairments of pragmatic language comprehension: (1) an insensitivity to irony, which is associated with poor theory-of-mind (i.e. a difficulty with inferring other people's thoughts); and (2) poor recognition of metaphors, which may reflect degraded semantics. This study investigated whether non-clinical high-schizotypal adults show similar impairments of pragmatic language. Thirty-six university students completed the Raine Schizotypal Personality Questionnaire, the Wechsler Memory Scale Logical-Memories subtest, Raven's Progressive Matrices and a story comprehension task that tested the ability to discriminate between incongruous statements and appropriate uses of ironical, metaphorical or literal speech. Counter to the pattern found for patients, high-schizotypal adults were just as capable as low-schizotypal adults of identifying appropriate metaphors, suggesting a discontinuity between schizophrenia and schizotypy for the metaphor-recognition problem. This study's finding of intact metaphor recognition in high-schizotypal adults contrasts with previous findings of poor proverb comprehension in these individuals and is interpreted in terms of different semantic processes required for recognizing and interpreting metaphors. Consistent with the pattern found for patients, high-schizotypal adults were significantly impaired in their ability to appreciate when a literally contradictory utterance could be interpreted as ironical, suggesting continuity between schizophrenia and schizotypy for the irony-appreciation problem.

Adolescent↗
PubMed2004

Is there a causal link from phonological awareness to success in learning to read?

In this review, we re-assess the evidence that phonological awareness represents a skill specific to spoken language that precedes and directly influences the process of reading acquisition. Longitudinal and experimental training studies are examined in detail, as these are considered most appropriate for exploring a causal hypothesis of this nature. A particular focus of our analysis is the degree to which studies to date have controlled for existing literacy skills in their participants and the influence that these skills might have on performance on phonological awareness tasks. We conclude that no study has provided unequivocal evidence that there is a causal link from competence in phonological awareness to success in reading and spelling acquisition. However, we believe that such a study is possible and outline some ideas for its design and implementation.

Awareness↗
PubMed2004

Are there lexicons?

Many models of the processing of printed or spoken words or objects or faces propose that systems of local representations of the forms of such stimuli--lexicons--exist. This is denied by partisans of the distributed-representation connectionist approach to cognitive modelling. An experimental paradigm of key theoretical importance here is lexical decision and its analogue in the domain of objects, object decision. How does each theoretical camp account for our ability to perform these two tasks? The localists say that the tasks are done by matching or failing to match a stimulus to a local representation in a lexicon. Advocates of distributed representations often do not seek to explain these two tasks; however, when they do, they propose that patterns of activation evoked in a semantic system can be used to discriminate between words and nonwords, or between real objects and false objects. Therefore the distributed-representation account of lexical and object decision tasks predicts that performance on these tasks can never be normal in patients with an impaired semantic system, nor in patients who cannot access semantics normally from the stimulus domain being tested. However, numerous such patients have been reported in the literature, indicating that semantic access is not needed for normal performance on these tasks. Such results support the localist form of modelling rather than the distributed-representation approach.

Agnosia↗
PubMed2004

Enlarged temporal lobes in Turner syndrome: an X-chromosome effect?

Gender differences in brain morphology have previously been reported in the temporal lobe and an 'X-chromosome dosage effect' has been described in Turner syndrome (45,X). To examine this further, we investigated temporal lobe morphology, metabolism and function in nine children with non-mosaic Turner syndrome using magnetic resonance imaging, (1)H magnetic resonance spectroscopy and neuropsychological testing and compared outcomes with results from nine age-matched control girls (46,XX). Turner subjects were found to have significantly larger superior temporal lobes (P = 0.004) and middle temporal lobes (P = 0.047) than controls. The size of the temporal lobe was found to correlate negatively with temporal lobe choline-containing compounds suggesting that increased temporal lobe size is associated with larger cells and/or decreased dendrites. This suggests a developmental failure to prune neurons. The degree of enlargement correlates negatively with functional performance on temporal-lobe associated tasks, suggesting that the enlargement may be a compensatory mechanism, or possibly causative in the case of semantic fluency performance. These temporal lobe abnormalities are discussed with reference to genes which are absent in Turner syndrome and to hormonal differences between Turner syndrome subjects and 46,XX controls.

Child↗
PubMed2004

Photographs of facial expression: accuracy, response times, and ratings of intensity.

Equal numbers of male and female participants judged which of seven facial expressions (anger, disgust, fear, happiness, neutrality, sadness, and surprise) were displayed by a set of 336 faces, and we measured both accuracy and response times. In addition, the participants rated how well the expression was displayed (i.e., the intensity of the expression). These three measures are reported for each face. Sex of the rater did not interact with any of the three measures. However, analyses revealed that some expressions were recognized more accurately in female than in male faces. The full set of these norms may be downloaded from www.psychonomic.org/archive/.

Facial Expression↗
PubMed2003

Modularity of music processing.

The music faculty is not a monolithic entity that a person either has or does not. Rather, it comprises a set of neurally isolable processing components, each having the potential to be specialized for music. Here we propose a functional architecture for music processing that captures the typical properties of modular organization. The model rests essentially on the analysis of music-related deficits in neurologically impaired individuals, but provides useful guidelines for exploring the music faculty in normal people, using methods such as neuroimaging.

Auditory Perception↗
PubMed2003

Electrophysiological correlates of anticipatory and poststimulus components of task switching.

Task-switching paradigms can shed light on cognitive and neural processes underlying attentional control mechanisms. An alternating runs task-switching paradigm (R. D. Rogers & S. Monsell, 1995) is used to identify ERP components associated with anticipatory and poststimulus components of task-switching processes. Subjects alternated between two tasks in a predictable series (AABB). Reaction time (RT) switch cost reduced with increasing response-stimulus (R-S) interval and a residual switch cost remained at the longest R-S interval. A switch-related positivity (D-Pos) developed in the R-S interval. D-Pos was time-locked to response onset, peaked around 400 ms post-response onset, and was unaffected by task-set interference. A switch-related negativity (D-Neg) emerged after stimulus onset. D-Neg peaked earlier with increasing R-S interval and its amplitude and latency were affected by task-set interference. D-Pos and D-Neg were interpreted within current models of task-switching.

Adolescent↗
PubMed2003

Cross-task strategic effects.

When easy and difficult items are mixed together, their reading aloud latencies become more homogeneous relative to their presentation in unmixed ("pure") conditions (Lupker, Brown, & Colombo, 1997). We report two experiments designed to investigate the nature of the mechanism that underlies this list composition, or blocking, effect. In Experiment 1, we replicated Lupker et al.'s (1997) blocking effect in the reading aloud task and extended these findings to the visual lexical decision task. In Experiment 2, we found that blocking effects generalized across tasks: The characteristics of stimuli in a visual lexical decision task influenced reading aloud latencies, and vice versa, when visual lexical decision and reading aloud trials were presented alternately in the same experiment. We discuss implications of these results within time-criterion (Lupker et al., 1997) and strength-of-processing (Kello & Plaut, 2000, 2003) theories of strategic processing in reading.

Decision Making↗
PubMed2003

When parallel processing in visual word recognition is not enough: new evidence from naming.

Low-frequency irregular words are named more slowly and are more error prone than low-frequency regular words (the regularity effect). Rastle and Coltheart (1999) reported that this irregularity cost is modulated by the serial position of the irregular grapheme-phoneme correspondence, such that words with early irregularities exhibit a larger cost than words with late ones. They argued that these data implicate rule-based serial processing, and they also reported a successful simulation with a model that has a rule-based serial component--the DRC model of reading aloud (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). However, Zorzi (2000) also simulated these data with a model that operates solely in parallel. Furthermore, Kwantes and Mewhort (1999) simulated these data with a serial processing model that has no rules for converting orthography to phonology. The human data reported by Rastle and Coltheart therefore neither require a serial processing account, nor successfully discriminate among a number of computational models of reading aloud. New data are presented wherein an interaction between the effects of regularity and serial position of irregularity is again reported for human readers. The DRC model simulated this interaction; no other implemented computational model does so. The present results are thus consistent with rule-based serial processing in reading aloud.

Humans↗
PubMed2003

Speed of lexical and nonlexical processing in French: the case of the regularity effect.

Words with irregular spelling-sound correspondences are read aloud more slowly than words with regular spelling-sound correspondences. This so-called regularity effect is modulated by word frequency, with low-frequency words showing larger costs than do high-frequency words. Because French has more regular spelling-to-sound correspondences than English, we expected a different pattern in French than in English. This was indeed the case, since regularity effects were obtained for both high- and low-frequency words in French. We further showed that a French implementation of the dual-route cascaded model could not account for this pattern. In additional simulations, we investigated whether this failure was due to lexical processes being too fast (leaving little time for the nonlexical route to interfere) or nonlexical processes being too slow. The results showed that only speeding up the nonlexical route allowed the model to capture the data. This suggests that the delayed phonology assumption that characterizes nonlexical processing in the original model needs to be abandoned in a more regular orthography.

Humans↗
PubMed2002

Paying attention to reading errors in acquired dyslexia.

The important role of selective attention in normal reading is illustrated by a relatively rare form of acquired dyslexia known as 'attentional dyslexia'. Theories of the functional deficit underlying this disorder differ as to the locus of the attentional dysfunction. A recent study by Mayall and Humphreys has contributed to this debate by studying letter migration errors in an attentional dyslexic.

Journal Article↗
PubMed2002

How predictable is spelling? Developing and testing metrics of phoneme-grapheme contingency.

Prior research has purported to show that words with infrequent phoneme-grapheme correspondences are more difficult to spell than words with frequent phoneme-grapheme correspondences. Defining exactly what a phoneme-grapheme relationship is, however, is not necessarily straightforward. There are a number of different assumptions that can be made. In this study, we developed four metrics of sound-spelling contingency based on all monosyllabic English words, including those with complex morphology. These metrics differed in the extent to which they included assumptions about spelling. The psychological reality of these different metrics was evaluated against data from a large-scale study of skilled adult spelling and a nonword spelling experiment. The results suggest that when spelling, people are sensitive to positional information, morphological status, vowel type, and a number of more idiosyncratic constraints.

Humans↗
PubMed2002

358,534 nonwords: the ARC Nonword Database.

The authors present a model of the phonotactic and orthographic constraints of Australian and Standard Southern British English monosyllables. This model is used as the basis for a web-based psycholinguistic resource, the ARC Nonword Database, which contains 358,534 monosyllabic nonwords--48,534 pseudohomophones and 310,000 non-pseudohomophonic nonwords. Items can be selected from the ARC Nonword Database on the basis of a wide variety of properties known or suspected to be of theoretical importance for the investigation of reading.

Databases as Topic↗
PubMed2002

The role of affect and reasoning in a patient with a delusion of misidentification.

INTRODUCTION: This study investigated a patient with a delusion of misidentification (DM) resembling a Capgras delusion. Instead of the typical Capgras delusion--the false belief that someone has been replaced by an almost identical impostor--patient MF misidentified his wife as his former business partner. METHOD: Detailed investigation of MF's face processing, affective response and affect perception, and ability to evaluate, and reject, implausible ideas was undertaken. RESULTS: MF's visual processing of identity, gender, and age of familiar and unknown faces was intact but he was unable to identify the facial expressions of anger, disgust, and fear, or to match faces across expressions. MF also showed a reduced affective responsiveness to his environment, and impaired reasoning ability. CONCLUSIONS: We propose that MF's delusion of misidentification resulted from a combination of affective deficits, including impairment of both affective response and affect perception, in addition to an inability to evaluate, and reject, implausible ideas. These deficits, in combination with specific life events at the time of onset of the delusion, may have contributed to the form and content of the delusion. In addition, the results raise the possibility that the processing of face identity and facial expression are not as independent as previously proposed in models of face processing.

Journal Article↗