Max Coltheart

Macquarie University, Sydney, New South Wales, Australia

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Publications (294)1008.87 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.
    Cortex 01/2016; DOI:10.1016/j.cortex.2015.10.009 · 5.13 Impact Factor
  • 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.
    Journal of Experimental Child Psychology 10/2015; 138. DOI:10.1016/j.jecp.2015.04.006 · 3.12 Impact Factor
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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.
    Psychonomic Bulletin & Review 08/2015; DOI:10.3758/s13423-015-0927-z · 2.99 Impact Factor
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    Betty Mousikou · Kathleen Rastle · Derek Besner · Max Coltheart ·
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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.
    Journal of Experimental Psychology Learning Memory and Cognition 07/2015; 41(4):1076-1099. DOI:10.1037/xlm0000090 · 2.86 Impact Factor
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    Max Coltheart ·

    World psychiatry: official journal of the World Psychiatric Association (WPA) 06/2015; 14(2):186-8. DOI:10.1002/wps.20214 · 14.23 Impact Factor
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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.
    Psychonomic Bulletin & Review 04/2015; DOI:10.3758/s13423-015-0835-2 · 2.99 Impact Factor
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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: [accessed Apr 29, 2015].
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    Robert Malcolm Ross · Ryan McKay · Max Coltheart · Robyn Langdon ·
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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:
    Schizophrenia Bulletin 01/2015; 41(5). DOI:10.1093/schbul/sbu187 · 8.45 Impact Factor
  • 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.
  • 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.

  • Psychology of Consciousness: Theory, Research, and Practice 01/2015; DOI:10.1037/cns0000059
  • Derek Besner · Darcy White · Max Coltheart ·

    Canadian Journal of Experimental Psychology 12/2014; 68(4):258-258. · 1.02 Impact Factor
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    Stephen C Pritchard · Max Coltheart · Eva Marinus · Anne Castles ·
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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.
    Psychonomics 2014, Long Beach, CA, USA; 11/2014
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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.
    Scientific Reports 11/2014; 4:7068. DOI:10.1038/srep07068 · 5.58 Impact Factor
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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.
    European Journal of Cognitive Psychology 10/2014; 26(8):831. DOI:10.1080/20445911.2014.968161 · 1.09 Impact Factor
  • 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.
    Topics in Cognitive Science 09/2014; 6(4). DOI:10.1111/tops.12108 · 2.88 Impact Factor
  • Claudio Mulatti · Lisa Ceccherini · Max Coltheart ·
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    ABSTRACT: In this work, we develop an empirically driven model of visual attention to multiple words using the word-word interference (WWI) task. In this task, two words are simultaneously presented visually: a to-be-ignored distractor word at fixation, and a to-be-read-aloud target word above or below the distractor word. Experiment 1 showed that low-frequency distractor words interfere more than high-frequency distractor words. Experiment 2 showed that distractor frequency (high vs. low) and target frequency (high vs. low) exert additive effects. Experiment 3 showed that the effect of the case status of the target (same vs. AlTeRnAtEd) interacts with the type of distractor (word vs. string of # marks). Experiment 4 showed that targets are responded to faster in the presence of semantically related distractors than in presence of unrelated distractors. Our model of visual attention to multiple words borrows two principles governing processing dynamics from the dual-route cascaded model of reading: cascaded interactive activation and lateral inhibition. At the core of the model are three mechanisms aimed at dealing with the distinctive feature of the WWI task, which is that two words are presented simultaneously. These mechanisms are identification, tokenization, and deactivation.
    Memory & Cognition 07/2014; 43(1). DOI:10.3758/s13421-014-0450-x · 1.92 Impact Factor
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    ABSTRACT: Mirrored-self misidentification delusion is the belief that one's reflection in the mirror is not oneself. This experiment used hypnotic suggestion to impair normal face processing in healthy participants and recreate key aspects of the delusion in the laboratory. From a pool of 439 participants, 22 high hypnotisable participants ("highs") and 20 low hypnotisable participants were selected on the basis of their extreme scores on two separately administered measures of hypnotisability. These participants received a hypnotic induction and a suggestion for either impaired (i) self-face recognition or (ii) impaired recognition of all faces. Participants were tested on their ability to recognize themselves in a mirror and other visual media - including a photograph, live video, and handheld mirror - and their ability to recognize other people, including the experimenter and famous faces. Both suggestions produced impaired self-face recognition and recreated key aspects of the delusion in highs. However, only the suggestion for impaired other-face recognition disrupted recognition of other faces, albeit in a minority of highs. The findings confirm that hypnotic suggestion can disrupt face processing and recreate features of mirrored-self misidentification. The variability seen in participants' responses also corresponds to the heterogeneity seen in clinical patients. An important direction for future research will be to examine sources of this variability within both clinical patients and the hypnotic model.
    Frontiers in Human Neuroscience 06/2014; 8. DOI:10.3389/fnhum.2014.00361 · 3.63 Impact Factor
  • Oren Griffiths · Robyn Langdon · Mike E Le Pelley · Max Coltheart ·
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    ABSTRACT: Introduction: There is now significant evidence that prediction error signalling is mediated by dopamine in the midbrain, and that dopamine dysfunction is implicated in people experiencing psychotic symptoms, including delusions. There has also been significant theorizing and experimentation concerning the remaining link in this triad, namely that deviant prediction error signalling produces or maintains psychotic symptoms. Methods: The research supporting the link between prediction error signalling and delusional symptoms was reviewed. Numerous studies indirectly support this link, but only one set of studies claim to directly test this hypothesis by combining three crucial elements: a patient sample, a manipulation of prediction error and neuroimaging. This particular set of studies were examined in detail. Results: Important methodological limitations in these studies were observed, and a reinterpretation of their data was offered. Conclusions: Methodological inconsistencies significantly weaken the claims made by these studies, but their data are consistent with current theorizing and they are instructive for future lines of inquiry in this field.
    Cognitive Neuropsychiatry 04/2014; 19(5). DOI:10.1080/13546805.2014.897601 · 1.91 Impact Factor
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    Petroula Mousikou · Max Coltheart ·
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    ABSTRACT: Reading aloud is faster when target words/nonwords are preceded by masked prime words/nonwords that share their first sound with the target (e.g., s ave-SINK) compared to when primes and targets are unrelated to each other (e.g., farm-SINK). This empirical phenomenon is the masked onset priming effect (MOPE) and is known to be due to serial left-to-right processing of the prime by a sublexical reading mechanism. However, the literature in this domain lacks a critical experiment. It is possible that when primes are real words their orthographic/phonological representations are activated in parallel and holistically during prime presentation, so any phoneme overlap between primes and targets (and not just initial-phoneme overlap) could facilitate target reading aloud. This is the prediction made by the only computational models of reading aloud that are able to simulate the MOPE, namely the DRC1.2.1, CDP+, and CDP++ models. We tested this prediction in the present study and found that initial-phoneme overlap ( b lip-BEST), but not end-phoneme overlap (flat -BEST), facilitated target reading aloud compared to no phoneme overlap (junk-BEST). These results provide support for a reading mechanism that operates serially and from left to right, yet are inconsistent with all existing computational models of single-word reading aloud.
    The Quarterly Journal of Experimental Psychology 04/2014; 67(11):2239-2246,. DOI:10.1080/17470218.2014.915332 · 4.67 Impact Factor

Publication Stats

15k Citations
1,008.87 Total Impact Points


  • 1988-2015
    • 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
  • 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
  • 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
      Exeter, England, United Kingdom
  • 1978-1988
    • Birkbeck, University of London
      Londinium, England, United Kingdom
  • 1973-1976
    • University of Reading
      • Department of Psychology
      Reading, ENG, United Kingdom
  • 1971-1972
    • University of Waterloo
      • Department of Psychology
      Waterloo, Ontario, Canada