Emer M E Forde

Aston University, Birmingham, England, United Kingdom

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Publications (25)130.59 Total impact

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    EMER M. E. FORDE
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    ABSTRACT: Patients with category specific recognition impairments for living and non living things have played a crucial role in developing current theories of semantic memory and object recognition. This paper reviews a number of the classic cases and discusses the theories that have been developed to account for these impairments. The first reports of patients with category specific recognition impairments for living and non living things were documented by Nielsen, who argued that they arose because living and non living things were stored in functionally and anatomically separate systems. Although this hypothesishas been reiterated in some recent papers, the most widespread view hasbeen that they emerge because living andnon living thingshave contrasting processing demands. The latter accounts include those which stress the relative importance of: the 'weighting of sensory and functional features associated with living and non living things; the role of structural similarity between objects; the role of direct experience with objects; direct links between perceptual and functional features; and category structure. These theories are reviewed before outlining our own view on why category specific recognition impairments emerge following brain damage.
    Preview · Article · Aug 2010 · Aphasiology
  • E M E Forde · J Rusted · N Mennie · M Land · G W Humphreys
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    ABSTRACT: We examined eye movements in a patient, FK, who has action disorganisation syndrome (ADS), as he performed the everyday task of making a cup of tea. We compared his eye movements with those of a person with Alzheimer's disease and with healthy volunteers. Despite showing very disorganised behaviour many aspects of FK's eye movements were relatively normal. However, unlike normal participants FK made no advance glances to objects that were about to be used, and he made increased numbers of fixations to irrelevant objects during the task. There were also differences in the durations of his eye movements during correct actions and during his perseverative and task-addition responses. We discuss the implications for understanding ADS and the cognitive processes required for correctly performing everyday tasks.
    No preview · Article · Feb 2010 · Neuropsychologia
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    Emer M E Forde · Glyn W Humphreys
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    ABSTRACT: We describe a patient (J.M.) who showed "refractory" behavior in picture-word matching tasks--that is, his performance became poorer when items were repeated. This contrasts with the facilitatory effects of repetition usually observed in normal participants. We show for the first time that there can be facilitatory effects of repetition on some tasks, even though refractory behavior is shown on the same items in other tasks. In particular, in Experiments 1 and 2, we demonstrate that J.M. showed contrasting effects of repetition across different components of the language system: There were facilitatory effects of repetition priming on lexical decision but refractory behavior on picture-word matching. In Experiments 3 and 4, we demonstrate that J.M. showed contrasting effects of repetition within the same system (semantic memory). His performance became refractory when items were repeated in picture-word matching (Experiment 3), but it was facilitated when items were repeated in superordinate categorization (Experiment 4). These contrasting patterns of facilitation and interference from repetition priming have implications for understanding the nature of refractory behavior and for constraining theoretical accounts of semantic memory.
    Preview · Article · Oct 2007 · Cognitive Affective & Behavioral Neuroscience
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    Richard Thomas · Emer Forde
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    ABSTRACT: We report a study on a patient (DW) with integrative visual agnosia and a category-specific recognition impairment for living things. We assessed DW's local and global processing and tested if his integrative agnosia could have led directly to his category-specific impairment. The main findings were: (i) DW was faster at identifying local compared to global letters. (ii) DW showed no local-to-global (or global-to-local) interference effects in selective attention tasks. (iii) DW showed a congruency effect in a divided attention task, suggesting that, when his attention was cued to both levels, he could process information simultaneously and integrate local and global information. (iv) Controls were poorer at naming nonliving compared to living things when presented with silhouettes. These data suggest that local and global information are differentially weighted in the visual recognition of living and nonliving things, and that an impairment in processing the overall shape of an object can lead to a category-specific deficit for living things. Crucially, this implies that category-specific impairments do not necessarily reflect damage to the semantic system, and models of semantic memory based on this assumption need to be revised.
    Full-text · Article · Feb 2006 · Neuropsychologia
  • Glyn W Humphreys · Emer M E Forde
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    ABSTRACT: We report data on patient FK, who presented with a marked deficit in accessing semantic knowledge about objects when tested across a range of input and output modalities. FK also showed a high degree of item-specific consistency in object identification, over and above effects due to object familiarity. We show that, despite being better at naming some objects than others, FK was equally poor at discriminating the superordinate categories of the stimuli. Also, he tended to be better at matching nameable items to a base-level label than to a superordinate-level label. We discuss the implications of the data for models of semantic memory.
    No preview · Article · Jul 2005 · Cognitive Neuropsychology
  • Emer M E Forde · Glyn W Humphreys
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    ABSTRACT: Recognition of orally spelt words is an unusual task, not commonly encountered in everyday life, but it can be surprising well preserved in patients with brain damage. There is, however, considerable debate over the cognitive abilities that are required to successfully perform this task. The main controversy has centred on whether oral spelling recognition is parasitic on the processes normally involved in spelling aloud or in reading. We describe a patient (FL) who showed a similar pattern of performance on reading and oral spelling recognition and was better at both tasks relative to spelling. We describe a second patient (FK) who was good at reading and reasonable at spelling but poor at reverse spelling. The patient data are not consistent with either of the following hypotheses: that oral spelling recognition is dependent either on a reading system that is functionally separate from a spelling system, or on a spelling system that is functionally separate from reading. We propose that the findings can, however, be accommodated by a model in which spelling and reading are not functionally independent systems, but share important cognitive components such as a graphemic buffer.
    No preview · Article · Mar 2005 · Cognitive Neuropsychology
  • Emer M E Forde · Glyn W Humphreys · Marietta Remoundou
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    ABSTRACT: We report data on stored knowledge of everyday tasks in a patient, FK, with 'action disorganisation syndrome'. In section 1, we analysed his explicit knowledge of the component actions, and their temporal order. FK showed generally impaired knowledge of everyday tasks relative to controls, and, when knowledge of the temporal order of the actions was probed, he showed particular impairments for the actions making up the final steps in tasks. In section 2 we assessed FK's implicit knowledge of the tasks, by evaluating how knowledge of the tasks influenced his ability to act out sets of instructions. We demonstrate that FK had some implicit knowledge of the tasks, but also, when actions had to be performed in the order as instructed, there was better knowledge of order for actions performed early rather than late in the task. We suggest that disordered task schema contributed to FK's deficits, with impairments on 'end' actions being vulnerable when task order was important for performance.
    No preview · Article · Mar 2004 · Neurocase
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    ABSTRACT: Using group functional Magnetic Resonance Imaging (fMRI) and group Magnetoencephalography (MEG) we studied two cognitive paradigms: A language task involving covert letter fluency and a visual task involving biological motion direction discrimination. The MEG data were analyzed using an adaptive beam-former technique known as Synthetic Aperture Magnetometry (SAM), which provides continuous 3-D images of cortical power changes. These images were spatially normalized and averaged across subjects to provide a group SAM image in the same template space as the group fMRI data. The results show that frequency-specific, task-related changes in cortical synchronization, detected using MEG, match those areas of the brain showing an evoked cortical hemodynamic response with fMRI. The majority of these changes were event-related desynchronizations (ERDs) in the 5-10 Hz and 15-25 Hz frequency ranges. Our study demonstrates how SAM, spatial normalization, and intersubject averaging enable group MEG studies to be performed. SAM analysis also allows the MEG experiment to have exactly the same task design as the corresponding fMRI experiment. This new analysis framework represents an important advance in the use of MEG as a cognitive neuroimaging technique and also allows mutual cross-validation with fMRI.
    No preview · Article · Jun 2002 · NeuroImage
  • Emer M E Forde · Glyn W Humphreys
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    ABSTRACT: We present a single case study of a patient, FK, who was severely impaired on routine, everyday tasks, such as preparing a cup of tea. We used the action coding system developed by Schwartz et al. to provide quantitative and qualitative measures of his performance in a number of experimental manipulations. In section A, we established FK's baseline performance on a range of tasks with (a) task-congruent objects only and (b) task-congruent objects and semantic distracters. In section B, we aimed to facilitate FK's performance by (a) giving him a pictorial representation of the goal, (b) giving him a set of written commands to follow, (c) giving him one command at a time, (d) demonstrating how the task should be performed and (e) dividing the task into smaller subgoals. We compared FK's performance with another patient, HG, to establish if there are qualitative differences between patients with 'action disorganization syndrome'. In section C, we aimed to hinder FK's performance by interrupting his execution of routine tasks. By comparing the factors that facilitated and impaired FK's performance in sections B and C, we hoped to isolate the key cognitive processes required to generate and control routine behaviour. In section D, we investigated how task demands impact on our ability to complete different everyday activities. The results of these experiments have important clinical implications for rehabilitation programmes for patients with action disorganization syndrome and can also help to distinguish between contemporary theoretical accounts of routine behaviour. In particular, we propose that patients who can be classified under the umbrella term of 'action disorganization syndrome' do not all have a reduction to 'non-specific cognitive resources' but can have qualitatively different impairments to a specialized action production system.
    No preview · Article · Feb 2002 · Neurocase
  • Emer M E Forde · Glyn W Humphreys
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    ABSTRACT: In this paper we examine the role of stored semantic knowledge in recall from short-term memory. We assessed the performance of a patient (FK), who showed a consistent lack of semantic knowledge for some words ('unknown') but not others ('known') on a range of serial recall tasks using both spoken and written words. Overall, FK was significantly better at recalling lists of known compared with unknown words. His recall of unknown words was characterized by numerous phonological errors, such as repeating 'bear skunk' as 'bunk scare'. FK showed a relatively normal primacy effect in immediate recall, but a striking lack of a recency effect. This pattern of performance is useful for constraining theoretical accounts of language production and verbal short-term memory and for understanding the role that long-term semantic knowledge may play in maintaining information in short-term memory.
    No preview · Article · Feb 2002 · Neurocase
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    ABSTRACT: We report a 12-year longitudinal case study on a 60-year-old male patient (DW) with category-specific agnosia. The extent to which DW's impairment has changed over time was evaluated using identical tests at time 1 (1988) and time 2 (2000). In particular, we assessed his ability to identify pictures and real objects, to draw from memory, and to access stored semantic information about living and non-living things. The principal findings were: (i). DW was significantly better at identifying real objects in comparison with line drawings. (ii). DW presented with a category-specific impairment for living things that remained consistent over the 12-year period. (iii). He significantly improved in his ability to identify real non-living objects over the 12-year period but real living objects remained at floor. (iv). His ability to access stored visual knowledge declined over time. On the basis of these data, we suggest that visual perception is required to maintain intact visual memories over a period of time. We also suggest that integrative visual agnosia co-occurs with a category-specific impairment for living things because the recognition of these items requires more global processing than for non-living things. In addition, we suggest that degradation to stored visual knowledge can cause category-specific naming impairments for living compared with non-living things because naming living things requires access to more detailed visual knowledge.
    Full-text · Article · Feb 2002 · Neurocase
  • Emer M E Forde · Glyn W Humphreys

    No preview · Article · Feb 2002 · Neurocase

  • No preview · Article · Nov 2001 · NeuroImage
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    G.W. Humphreys · E.M.E. Forde
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    ABSTRACT: Category-specific impairments of object recognition and naming are among the most intriguing disorders in neuropsychology, affecting the retrieval of knowledge about either living or nonliving things. They can give us insight into the nature of our representations of objects: Have we evolved different neural systems for recognizing different categories of object? What kinds of knowledge are important for recognizing particular objects? How does visual similarity within a category influence object recognition and representation? What is the nature of our semantic knowledge about different objects? We review the evidence on category-specific impairments, arguing that deficits even for one class of object (e.g., living things) cannot be accounted for in terms of a single information processing disorder across all patients; problems arise at contrasting loci in different patients. The same apparent pattern of impairment can be produced by damage to different loci. According to a new processing framework for object recognition and naming, the hierarchical interactive theory (HIT), we have a hierarchy of highly interactive stored representations. HIT explains the variety of patients in terms of (1) lesions at different levels of processing and (2) different forms of stored knowledge used both for particular tasks and for particular categories of object.
    Preview · Article · Jul 2001 · Behavioral and Brain Sciences
  • Glyn W.  Humphreys  · Emer M. E.  Forde 
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    ABSTRACT: We summarise and respond to the main points made by the commentators on our target article, which concern: (1) whether structural similarity can play a causal role in normal object identification and in neuropsychological deficits for living things, (2) the nature of our structural knowledge of the world, (3) the relations between sensory and functional knowledge of objects, and the nature of our functional knowledge about living things, (4) whether we need to posit a “core” semantic system, (5) arguments that can be marshalled from evidence on functional imaging, (6) the causal mechanisms by which category differences can emerge in object representations, and (7) the nature of our knowledge about categories other than living and nonliving things. We also highlight points raised in our article that seem to be accepted.
    No preview · Article · May 2001 · Behavioral and Brain Sciences
  • E M Forde · G W Humphreys
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    ABSTRACT: Category-specific impairments of object recognition and naming are among the most intriguing disorders in neuropsychology, affecting the retrieval of knowledge about either living or nonliving things. They can give us insight into the nature of our representations of objects: Have we evolved different neural systems for recognizing different categories of object? What kinds of knowledge are important for recognizing particular objects? How does visual similarity within a category influence object recognition and representation? What is the nature of our semantic knowledge about different objects? We review the evidence on category-specific impairments, arguing that deficits even for one class of object (e.g., living things) cannot be accounted for in terms of a single information processing disorder across all patients; problems arise at contrasting loci in different patients. The same apparent pattern of impairment can be produced by damage to different loci. According to a new processing framework for object recognition and naming, the hierarchical interactive theory (HIT), we have a hierarchy of highly interactive stored representations. HIT explains the variety of patients in terms of (1) lesions at different levels of processing and (2) different forms of stored knowledge used both for particular tasks and for particular categories of object.
    No preview · Article · Jan 2001 · Behavioral and Brain Sciences
  • G W Humphreys · E M Forde
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    ABSTRACT: Category-specific impairments of object recognition and naming are among the most intriguing disorders in neuropsychology, affecting the retrieval of knowledge about either living or nonliving things. They can give us insight into the nature of our representations of objects: Have we evolved different neural systems for recognizing different categories of object? What kinds of knowledge are important for recognizing particular objects? How does visual similarity within a category influence object recognition and representation? What is the nature of our semantic knowledge about different objects? We review the evidence on category-specific impairments, arguing that deficits even for one class of object (e.g., living things) cannot be accounted for in terms of a single information processing disorder across all patients; problems arise at contrasting loci in different patients. The same apparent pattern of impairment can be produced by damage to different loci. According to a new processing framework for object recognition and naming, the hierarchical interactive theory (HIT), we have a hierarchy of highly interactive stored representations. HIT explains the variety of patients in terms of (1) lesions at different levels of processing and (2) different forms of stored knowledge used both for particular tasks and for particular categories of object.
    No preview · Article · Jan 2001 · Behavioral and Brain Sciences
  • Emer M.E. Forde · Glyn W. Humphreys
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    ABSTRACT: We present a single case study of a patient, HG, who was severely impaired on routine everyday tasks, such as cleaning his teeth and preparing a cup of tea. We used the Action Coding System developed by Schwartz et al. (1991) to provide quantitative and qualitative measures of his performance in a number of experimental manipulations: (a) with task-congruent objects only, (b) with task-congruent objects and semantic distractors, (c) with a set of written commands to follow, (d) when he was given one command at a time, (e) when he was shown how the task should be performed before starting himself, and (f) when the task was divided into smaller subgoals. In general, the majority of HG's errors were step omissions, perseverations, sequence errors, and semantic errors. These semantic errors are particularly interesting since HG was able to name, gesture to, and define all the objects when they were presented in isolation or in task-congruent arrays. We suggest that semantic errors may arise for a number of reasons: (1) impaired access from semantic memory to a network representing action schema, (2) degradation of stored schema, and (3) behavior that is abnormally driven by the goal, by preceding actions, or by salient objects rather than by an appropriate association between these elements in working memory.
    No preview · Article · Dec 2000 · Brain and Cognition
  • G. W. Humphreys · E. M. E. Forde · D. Francis
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    ABSTRACT: Successful performance on many everyday tasks depends on the ability to recognize the objects involved, stored knowledge about the steps in the action, the ability to organize the steps in the correct temporal order, and maintenance of information about the steps completed. Insights into these abilities and their interrelations can be gained by studying the breakdown of performance, either after brain damage or when people perform tasks with forms of processing load imposed. We report data from patients with the neuropsychological deficit "action disorganization syndrome" (ADS) and from normal subjects under dual-task conditions, demonstrating the fractionation of some of these abilities. ADS can entail deficits in long-term knowledge for the component steps and their orders, in actions, and in inhibiting component actions already completed. Moreover, the problems ADS patients have in maintaining the steps within a complex action sequence interact with learned knowledge about familiar object usage, which can be invoked directly by objects. Qualitatively similar effects can be observed in control subjects under dual-task conditions. We discuss the implications of the results for understanding how sequential behavior is organized in complex tasks.
    No preview · Article · Jan 2000
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    E Forde · Adriane E Seiffert

    Preview · Article · Aug 1999 · Perception