Max Coltheart

Macquarie University, Sydney, New South Wales, Australia

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Publications (310)1043.59 Total impact

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    ABSTRACT: This study examined the importance of prefixes as sublexical cues for stress assignment during reading aloud English disyllabic words. In particular, we tested the hypothesis that prefixes repel stress (Rastle & Coltheart, 2000) by investigating the likelihood with which patients with surface dyslexia assign second-syllable stress to prefixed words. Five such patients were presented with three types of disyllabic words for reading aloud: ‘regular’ prefixed words with weak-strong stress pattern (e.g., remind); ‘irregular’ prefixed words with strong-weak stress pattern (e.g., reflex); and non-prefixed words with strong-weak stress pattern (e.g., scandal). Results showed that all five patients frequently regularized the strong-weak prefixed words by pronouncing them with second syllable stress. These regularization errors provide strong evidence for the functional role of prefixes in stress assignment during reading. Additional computational simulations using the rule-based algorithm for pronouncing disyllables developed by Rastle and Coltheart (2000) and the CDP++ model of reading aloud (Perry et al., 2010) allowed us to evaluate how these two opponent approaches to reading aloud fare in respect of the patient data.
    Full-text · Article · Jan 2016 · Cortex
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    ABSTRACT: The present article investigates how phonotactic rules constrain oral reading in the Russian language. The pronunciation of letters in Russian is regular and consistent, but it is subject to substantial phonotactic influence: the position of a phoneme and its phonological context within a word can alter its pronunciation. In Part 1 of the article, we analyze the orthography-to-phonology and phonology-to-phonology (i.e., phonotactic) relationships in Russian monosyllabic words. In Part 2 of the article, we report empirical data from an oral word reading task that show an effect of phonotactic dependencies on skilled reading in Russian: humans are slower when reading words where letter-phoneme correspondences are highly constrained by phonotactic rules compared with those where there are few or no such constraints present. A further question of interest in this article is how computational models of oral reading deal with the phonotactics of the Russian language. To answer this question, in Part 3, we report simulations from the Russian dual-route cascaded model (DRC) and the Russian connectionist dual-process model (CDP++) and assess the performance of the 2 models by testing them against human data. (PsycINFO Database Record
    No preview · Article · Dec 2015 · Journal of Experimental Psychology Learning Memory and Cognition
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    Anastasia Ulicheva · Max Coltheart
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    ABSTRACT: A word whose body is pronounced in different ways in different words is body-inconsistent. When we take the unit that precedes the vowel into account for the calculation of body-consistency, the proportion of English words that are body-inconsistent is considerably reduced at the level of corpus analysis, prompting the question of whether humans actually use such head/onset-conditioning when they read. Methods. Four metrics for head/onset-constrained body-consistency were calculated: by the last grapheme of the head, by the last phoneme of the onset, by place and manner of articulation of the last phoneme of the onset, and by manner of articulation of the last phoneme of the onset. Since these were highly correlated, principal component analysis was performed on them. Results. Two out of four resulting principal components explained significant variance in the reading-aloud reaction times, beyond regularity and body-consistency. Discussion. Humans read head/onset-conditioned words faster than would be predicted based on their body-consistency and regularity only. We conclude that humans are sensitive to the dependency between word-beginnings and word-ends when they read aloud, and that this dependency is phonological in nature, rather than orthographic.
    Full-text · Article · Dec 2015 · PeerJ
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    Full-text · Dataset · Nov 2015
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    ABSTRACT: Phonological decoding is central to learning to read, and deficits in its acquisition have been linked to reading disorders such as dyslexia. Understanding how this skill is acquired is therefore important for characterising reading difficulties. Decoding can be taught explicitly, or implicitly learned during instruction on whole word spellings and pronunciation. This study describes the design and testing of a new grapheme–phoneme correspondence (GPC) rule learning model (GPC-LM), based on earlier work by Coltheart, Curtis, Atkins, and Haller. It simulates the implicit deduction of GPCs. These learned GPCs are tested in conjunction with the dual-route cascaded model of reading aloud. The new model learns many productive GPCs and achieves good word reading performance without lexical route participation. Nonword pronunciation using the learned GPCs also more closely matched human data than achieved by the connectionist dual-process models (CDP+/++). Despite this, challenges regarding psychological plausibility remain, and are discussed.
    Full-text · Article · Nov 2015 · Scientific Studies of Reading
  • Rachel A. Robbins · Max Coltheart
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    ABSTRACT: Children have been shown to be worse at face recognition than adults even into their early teens. However, there is debate about whether this is due to face-specific mechanisms or general perceptual and memory development. Here, we considered a slightly different option-that children use different cues to recognition. To test this, we showed 8-year-olds, 10-year-olds, and adults whole body, head only, and body only stimuli that were either moving or static. These were shown in two tasks, a match-to-sample task with unfamiliar people and a learning task, to test recognition of experimentally familiar people. On the match-to-sample task, children were worse overall, but the pattern of results was the same for each age group. Matching was best with all cues or head available, and there was no effect of movement. However, matching was generally slower with moving stimuli, and 8-year-olds, but not 10-year-olds, were slower than adults. In general, more cues were faster than heads or bodies alone, but 8-year-olds were surprisingly slow when still bodies were shown alone. On the learning task, again all age groups showed similar patterns, with better performance for all cues. Both 8- and 10-year-olds were more likely to say that they knew someone unfamiliar. Again, movement did not provide a clear advantage. Overall, this study suggests that any differences in face recognition between adults and children are not due to differences in cue use and that instead these results are consistent with general improvements in memory. Copyright © 2015 Elsevier Inc. All rights reserved.
    No preview · Article · Oct 2015 · Journal of Experimental Child Psychology
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    ABSTRACT: Masked priming studies have repeatedly provided evidence for a form-based morpho-orthographic segmentation mechanism that blindly decomposes any word with the mere appearance of morphological complexity (e.g., corn + er). This account has been called into question by Baayen et al. Psychological Review, 118, 438-482 (2011), who pointed out that the prime words previously tested in the morpho-orthographic condition vary in the extent to which the suffix conveys regular meaning. In the present study, we investigated whether evidence for morpho-orthographic segmentation can be obtained with a set of tightly controlled prime words that are entirely semantically opaque. Using a visual lexical decision task, we compared priming from truly suffixed primes (hunter-HUNT), completely opaque pseudo-suffixed primes (corner-CORN), and non-suffixed primes (cashew-CASH). The results show comparable magnitudes of priming for the truly suffixed and pseudo-suffixed primes, and no priming from non-suffixed primes, and therefore provide further important evidence in support of morpho-orthographic segmentation processes operating in the absence of any possible role for semantics.
    Full-text · Article · Aug 2015 · Psychonomic Bulletin & Review
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    ABSTRACT: Dual-route theories of reading posit that a sublexical reading mechanism that operates serially and from left to right is involved in the orthography-to-phonology computation. These theories attribute the Masked Onset Priming Effect (MOPE) and the Phonological Stroop Effect (PSE) to the serial left-to-right operation of this mechanism. However, both effects may arise during speech planning, in the phonological encoding process, which also occurs serially and from left to right. In the present paper, we sought to determine the locus of serial processing in reading aloud by testing the contrasting predictions that the dual-route and speech planning accounts make in relation to the MOPE and the PSE. The results from three experiments that used the MOPE and the PSE paradigms in English are inconsistent with the idea that these effects arise during speech planning, and consistent with the claim that a sublexical serially-operating reading mechanism is involved in the print-to-sound translation. Simulations of the empirical data on the MOPE with the DRC and CDP++ models, which are computational implementations of the dual-route theory of reading, provide further support for the dual-route account.
    Full-text · Article · Jul 2015 · Journal of Experimental Psychology Learning Memory and Cognition
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    Max Coltheart

    Preview · Article · Jun 2015 · World psychiatry: official journal of the World Psychiatric Association (WPA)
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    Xenia Schmalz · Eva Marinus · Max Coltheart · Anne Castles
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    ABSTRACT: Orthographic depth has been studied intensively as one of the sources of cross-linguistic differences in reading, and yet there has been little detailed analysis of what is meant by orthographic depth. Here we propose that orthographic depth is a conglomerate of two separate constructs: the complexity of print-to-speech correspondences and the unpredictability of the derivation of the pronunciations of words on the basis of their orthography. We show that on a linguistic level, these two concepts can be dissociated. Furthermore, we make different predictions about how the two concepts would affect skilled reading and reading acquisition. We argue that refining the definition of orthographic depth opens up new research questions. Addressing these can provide insights into the specific mechanisms by which language-level orthographic properties affect cognitive processes underlying reading.
    Full-text · Article · Apr 2015 · Psychonomic Bulletin & Review
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    Xenia Schmalz · Eva Marinus · Max Coltheart · Anne Castles
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    ABSTRACT: Orthographic depth has been studied intensively as one of the sources of cross-linguistic differences in reading, and yet there has been little detailed analysis of what is meant by orthographic depth. Here we propose that orthographic depth is a conglomerate of two separate constructs: the complexity of print-to-speech correspondences and the unpredictability of the derivation of the pronunciations of words on the basis of their orthography. We show that on a linguistic level, these two concepts can be dissociated. Furthermore, we make different predictions about how the two concepts would affect skilled reading and reading acquisition. We argue that refining the definition of orthographic depth opens up new research questions. Addressing these can provide insights into the specific mechanisms by which language-level orthographic properties affect cognitive processes underlying reading. Getting to the bottom of orthographic depth.. Available from: https://www.researchgate.net/publication/275217141_Getting_to_the_bottom_of_orthographic_depth [accessed Apr 29, 2015].
    Full-text · Article · Apr 2015
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    ABSTRACT: It has been claimed that delusional and delusion-prone individuals have a tendency to gather less data before forming beliefs. Most of the evidence for this "jumping to conclusions" (JTC) bias comes from studies using the "beads task" data-gathering paradigm. However, the evidence for the JTC bias is mixed. We conducted a random-effects meta-analysis of individual participant data from 38 clinical and nonclinical samples (n = 2,237) to investigate the relationship between data gathering in the beads task (using the "draws to decision" measure) and delusional ideation (as indexed by the "Peters et al Delusions Inventory"; PDI). We found that delusional ideation is negatively associated with data gathering (r s = -0.10, 95% CI [-0.17, -0.03]) and that there is heterogeneity in the estimated effect sizes (Q-stat P = .03, I (2) = 33). Subgroup analysis revealed that the negative association is present when considering the 23 samples (n = 1,754) from the large general population subgroup alone (r s = -0.10, 95% CI [-0.18, -0.02]) but not when considering the 8 samples (n = 262) from the small current delusions subgroup alone (r s = -0.12, 95% CI [-0.31, 0.07]). These results provide some provisional support for continuum theories of psychosis and cognitive models that implicate the JTC bias in the formation and maintenance of delusions. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.
    Full-text · Article · Jan 2015 · Schizophrenia Bulletin
  • M. Coltheart
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    ABSTRACT: In this overview, Author presents the development of his approach-the twofactor account of delusions-drawing attention to the neuropsychological research on delusions (the role of brain damage in the formation of delusions), as well as to the differences between explaining monothematic and polythematic delusions (this differentiation is not analyzed in detail in the present volume). He also sketches the most promising issues in the current research on delusions.
    No preview · Article · Jan 2015
  • M.H. Connors · R. Langdon · M. Coltheart
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    ABSTRACT: Misidentification delusions involve an incorrect belief about the identity of other people, oneself, animals, objects, or places. Examples include Capgras delusion (the belief that a person or animal has been replaced by a visually similar impostor), the delusion of inanimate doubles (the belief that objects have been replaced by replicas), and reduplicative paramnesia (the belief that a person or place has been duplicated). Although encompassing a wide range of different beliefs, misidentification delusions share two common elements: 1) a misidentified entity, and 2) an incorrect belief about the identity of that entity. Misidentification delusions can occur in many different clinical conditions. These include, for example, schizophrenia, dementia, affective disorders, stroke, and traumatic brain injury. This chapter reviews different types of misidentification delusions, examining the etiology and prevalence of misidentification delusions and offering a theoretical explanation based on Langdon and Coltheart's two-factor theory of delusions.
    No preview · Article · Jan 2015

  • No preview · Article · Jan 2015 · Psychology of Consciousness: Theory, Research, and Practice
  • Derek Besner · Darcy White · Max Coltheart

    No preview · Article · Dec 2014 · Canadian Journal of Experimental Psychology
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    ABSTRACT: The self-teaching hypothesis (Share, 1995) describes a psychologically plausible process by which people learn to read without constant supervision. Despite being highly regarded and supported by a good deal of empirical investigation, the self-teaching hypothesis has not been widely explored computationally. A computational cognitive model affords greater rigour than is possible when considering a purely verbal cognitive theory. In this research, we simulated the self-teaching hypothesis using an adapted version of the dual-route cascaded (DRC) model of visual word recognition and reading aloud. This model allows a quantitative exploration of the complex interaction between sublexical knowledge, contextual ambiguity and word regularity associated with learning to read English, all while effectively simulating the self-teaching hypothesis in action. We present here a thorough account of this new model and its theoretical commitments, and also present the results from a range of simulations exploring the model’s operation and plausibility.
    Full-text · Conference Paper · Nov 2014
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    Jing Zhao · Yi Qian · Hong-Yan Bi · Max Coltheart
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    ABSTRACT: The visual magnocellular-dorsal (M-D) deficit theory of developmental dyslexia (DD) is still highly debated. Many researchers have made great efforts to investigate the relationship between M-D dysfunction and reading disability. Given that visual analysis plays an important role in Chinese reading, the present study tried to examine how the M-D dysfunction affected Chinese character recognition in Chinese children with DD. Sixteen DD children with M-D deficit, fifteen DD children with normal M-D function and twenty-seven age-matched typically developing children participated in this study. A global/local decision task was adopted, in which we manipulated the spatial frequency of target characters to separate an M-D condition from an unfiltered condition. Results of reaction times and error rates showed that in the M-D condition both M-D normal dyslexics and controls exhibited a significant global precedence effect, with faster responses and lower error rates in global decision than in local decision. In contrast, this global advantage was absent for the M-D impaired dyslexics. Accordingly, we propose that the M-D impairment present in some but not all dyslexics might influence global recognition of Chinese characters in this subgroup of children with DD, which might be implicated in their difficulties in learning to read.
    Full-text · Article · Nov 2014 · Scientific Reports
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    ABSTRACT: The type of sublexical correspondences employed during non-word reading has been a matter of considerable debate in the past decades of reading research. Non-words may be read either via small units (graphemes) or large units (orthographic bodies). In addition, grapheme-to-phoneme correspondences may involve context-sensitive correspondences, such as pronouncing an “a” as /ɔ/ when preceded by a “w”. Here, we use an optimisation procedure to explore the reliance on these three types of correspondences in non-word reading. In Experiment 1, we use vowel length in German to show that all three sublexical correspondences are necessary and sufficient to predict the participants' responses. We then quantify the degree to which each correspondence is used. In Experiment 2, we present a similar analysis in English, which is a more complex orthographic system.
    Full-text · Article · Oct 2014 · European Journal of Cognitive Psychology
  • Robyn Langdon · Emily Connaughton · Max Coltheart
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    ABSTRACT: Fregoli delusion is the mistaken belief that some person currently present in the deluded person's environment (typically a stranger) is a familiar person in disguise. The stranger is believed to be psychologically identical to this known person (who is not present) even though the deluded person perceives the physical appearance of the stranger as being different from the known person's typical appearance. To gain a deeper understanding of this contradictory error in the normal system for tracking and identifying known persons, we conducted a detailed survey of all the Fregoli cases reported in the literature since the seminal Courbon and Fail (1927) paper. Our preliminary reading of these cases revealed a notable lack of definitional clarity. So, we first formulated a classification scheme of different person misidentification delusions so as to identify those cases that qualified as instances of Fregoli according to the above characterization: the mistaken belief that a known person is present in the environment in a different guise to his or her typical appearance. We identified 38 clear cases of this type and set out to answer a series of questions motivated by current hypotheses about the origin of the Fregoli delusion. We asked whether the patients misidentified particular strangers, made reference to the misidentified known persons using wigs or plastic surgery (or other techniques to disguise their appearance), misidentified many different strangers or only one, showed other symptoms (in particular, other misidentification delusions), and made inferences about the motives of the known persons in disguise. We conclude by discussing the implications of our findings for current hypotheses concerning the origin of the Fregoli delusion.
    No preview · Article · Sep 2014 · Topics in Cognitive Science

Publication Stats

16k Citations
1,043.59 Total Impact Points

Institutions

  • 1988-2016
    • Macquarie University
      • • Department of Cognitive Science
      • • ARC Centre of Excellence for Cognition and its Disorders
      • • Macquarie Centre for Cognitive Science (MACCS)
      • • Department of Psychology
      Sydney, New South Wales, Australia
  • 2013
    • University of London
      Londinium, England, United Kingdom
  • 2010
    • Vrije Universiteit Brussel
      Bruxelles, Brussels Capital, Belgium
  • 2009
    • Children's Hospital at Westmead
      • Developmental Cognitive Neuropsychology Research Unit (DeCog)
      Sydney, New South Wales, Australia
  • 2008
    • University of Leeds
      • Institute of Psychological Sciences
      Leeds, England, United Kingdom
  • 2005
    • University of Melbourne
      Melbourne, Victoria, Australia
  • 2001
    • University of Sydney
      • School of Psychology
      Sydney, New South Wales, Australia
  • 2000
    • University of Cambridge
      Cambridge, England, United Kingdom
    • Royal Prince Alfred Hospital
      Camperdown, New South Wales, Australia
    • Deakin University
      • School of Psychology
      Geelong, Victoria, Australia
  • 1996
    • University of Exeter
      • Department of Psychology
      Exeter, England, United Kingdom
  • 1995
    • University of Wollongong
      • School of Psychology
      City of Greater Wollongong, New South Wales, Australia
  • 1978-1988
    • Birkbeck, University of London
      Londinium, England, United Kingdom
  • 1973-1976
    • University of Reading
      • Department of Psychology
      Reading, ENG, United Kingdom
  • 1971-1974
    • University of Waterloo
      • Department of Psychology
      Ватерлоо, Ontario, Canada
  • 1969
    • Monash University (Australia)
      • School of Psychology and Psychiatry
      Melbourne, Victoria, Australia