John Dunn | The University of Adelaide (original) (raw)
Papers by John Dunn
Proceedings of the National Academy of Sciences of the United States of America, Jan 22, 2015
Laboratory-based mock crime studies have often been interpreted to mean that (i) eyewitness confi... more Laboratory-based mock crime studies have often been interpreted to mean that (i) eyewitness confidence in an identification made from a lineup is a weak indicator of accuracy and (ii) sequential lineups are diagnostically superior to traditional simultaneous lineups. Largely as a result, juries are increasingly encouraged to disregard eyewitness confidence, and up to 30% of law enforcement agencies in the United States have adopted the sequential procedure. We conducted a field study of actual eyewitnesses who were assigned to simultaneous or sequential photo lineups in the Houston Police Department over a 1-y period. Identifications were made using a three-point confidence scale, and a signal detection model was used to analyze and interpret the results. Our findings suggest that (i) confidence in an eyewitness identification from a fair lineup is a highly reliable indicator of accuracy and (ii) if there is any difference in diagnostic accuracy between the two lineup formats, it li...
Scientific reports, 2015
People frequently change their preferences for options of gambles which they play once compared t... more People frequently change their preferences for options of gambles which they play once compared to those they play multiple times. In general, preferences for repeated play gambles are more consistent with the expected values of the options. According to the one-process view, the change in preference is due to a change in the structure of the gamble that is relevant to decision making. According to the two-process view, the change is attributable to a shift in the decision making strategy that is used. To adjudicate between these two theories, we asked participants to choose between gambles played once or 100 times, and to choose between them based on their expected value. Consistent with the two-process theory, we found a set of brain regions that were sensitive to the extent of behavioral change between single and aggregated play and also showed significant (de)activation in the expected value choice task. These results support the view that people change their decision making str...
Psychological Review, 2004
This article critically examines the view that the signal detection theory (SDT) interpretation o... more This article critically examines the view that the signal detection theory (SDT) interpretation of the remember-know (RK) paradigm has been ruled out by the evidence. The author evaluates 5 empirical arguments against a database of 72 studies reporting RK data under 400 different conditions. These arguments concern (a) the functional independence of remember and know rates, (b) the invariance of estimates of sensitivity, (c) the relationship between remember rates and overall hit and false alarm rates, (d) the relationship between RK responses and confidence judgments, and (e) dissociations between remember and overall hit rates. Each of these arguments is shown to be flawed, and despite being open to refutation, the SDT interpretation is consistent with existing data from both the RK and rememberknow-guess paradigms and offers a basis for further theoretical development.
Psychological Review, 2008
This article addresses the issue of whether the remember-know (RK) task is best explained by a si... more This article addresses the issue of whether the remember-know (RK) task is best explained by a single-process or a dual-process model. All single-process models propose that remember and know responses reflect different levels of a single strength-of-evidence dimension. Thus, across conditions in which response criteria are held constant, these models predict that the RK task is unidimensional. Many dual-process models propose that remember and know responses reflect two qualitatively distinct processes underlying recognition memory, often characterized as recollection and familiarity. These models predict that the RK task is bidimensional. Using data from 37 studies, the author conducted a state-trace analysis to determine the dimensionality of the RK task. In those studies, non-memory-related differences between conditions were eliminated via decision criteria constrained to be constant across all levels of the independent variables. The results reveal little or no evidence of bidimensionality and lend additional support to the unequal-variance signal detection model. Other arguments supporting a bidimensional interpretation are examined, and the author concludes there is insufficient evidence for the RK task to be used to identify qualitatively different memory components.
Psychological Review, 1988
Psychological Research Psychologische Forschung, 2000
A recent controversy in the ®eld of depth perception has highlighted an important aspect of model... more A recent controversy in the ®eld of depth perception has highlighted an important aspect of model testing concerning a model's complexity, de®ned as the prior propensity of the model to ®t arbitrary data sets. The present article introduces an index of complexity, called the mean minimum distance, de®ned as the average squared distance between an arbitrary data point and the prediction range of the model. It may also be expressed as a dimensionless quantity called the scaled mean minimum distance. For linear models, theoretical values for the scaled mean minimum distance and the variance of the scaled minimum distance can be readily obtained and compared against empirical estimates obtained from ®ts to random data. The approach is applied to resolving the question of the relative complexity of the Linear Integration model and the Fuzzy Logic of Perception model, both of which have been the subject of controversy in the ®eld of depth perception. It is concluded that the two models are equally complex.
Journal of Mathematical Psychology, 2003
Psychological constructs can only be measured indirectly in terms overt behavior, often by means ... more Psychological constructs can only be measured indirectly in terms overt behavior, often by means of changes in the level of performance on tasks they are presumed to affect. However, the exact relationship between constructs and the tasks they are presumed to affect is usually not known, which often requires non-essential auxiliary assumptions to be added to a psychological model to allow it to contact the data. Signed difference analysis is a method of deriving testable consequences from psychological models under the general assumption that the relationship between task performance and the constructs or combinations of constructs postulated by the model is at least monotonic. The predictions derived using signed difference analysis do not depend upon estimation of either model parameters or explicit functional relationships. In the present paper, the mathematical theory of signed difference analysis is presented and applied to illustrative problems drawn from research in memory, spatial attention, and reading. The relationships between signed difference analysis and related inferential procedures such as conjoint measurement, statetrace analysis, and double dissociation are discussed. r
Journal of Experimental Psychology: Learning, Memory, and Cognition, 2012
Evidence that learning rule-based (RB) and information-integration (II) category structures can b... more Evidence that learning rule-based (RB) and information-integration (II) category structures can be dissociated across different experimental variables has been used to support the view that such learning is supported by multiple learning systems. Across 4 experiments, we examined the effects of 2 variables, the delay between response and feedback and the informativeness of feedback, which had previously been shown to dissociate learning of the 2 types of category structure. Our aim was twofold: first, to determine whether these dissociations meet the more stringent inferential criteria of state-trace analysis and, second, to determine the conditions under which they can be observed. Experiment 1 confirmed that a mask-filled feedback delay dissociated the learning of RB and II category structures with minimally informative (yes/no) feedback and also met the state-trace criteria for the involvement of multiple latent variables. Experiment 2 showed that this effect is eliminated when a less similar, fixed pattern mask is presented in the interval between response and feedback. Experiment 3 showed that the selective effect of feedback delay on II learning is reduced with fully informative feedback (in which the correct category is specified after an incorrect response) and that feedback type did not dissociate RB and II learning. Experiment 4 extended the results of Experiment 2, showing that the differential effect of feedback delay is eliminated when a fixed pattern mask is used. These results pose important challenges to models of category learning, and we discuss their implications for multiple learning system models and their alternatives.
Journal of Clinical and Experimental Neuropsychology (Neuropsychology, Development and Cognition: Section A), 2002
The aim of this study was to compare traditional methods of scoring the Logical Memory test of th... more The aim of this study was to compare traditional methods of scoring the Logical Memory test of the Wechsler Memory Scale-III with a new method based on Latent Semantic Analysis (LSA). LSA represents texts as vectors in a high-dimensional semantic space and the similarity of any two texts is measured by the cosine of the angle between their respective vectors. The Logical Memory test was administered to a sample of 72 elderly individuals, 14 of whom were classi®ed as cognitively impaired by the Mini-Mental State Examination (MMSE). The results showed that LSA was at least as valid and sensitive as traditional measures. Partial correlations between prose recall measures and measures of cognitive function indicated that LSA explained all the relationship between Logical Memory and general cognitive function. This suggests that LSA may serve as an improved measure of prose recall.
Cortex, 2003
The joint aim of cognitive psychology and cognitive neuropsychology is to describe the functional... more The joint aim of cognitive psychology and cognitive neuropsychology is to describe the functional architecture of the human mind. That is, to identify, characterize, and enumerate the fundamental mental processes underlying human behaviour. In both of these fields, behaviour is measured in terms of performance on a wide range of tasks that are presumed to involve different combinations of mental functions. The two fields differ primarily in the nature of the conditions under which these tasks are performed. Specifically, whereas cognitive psychology generally involves systematic manipulation of variables in experiments involving non-brain damaged participants, cognitive neuropsychology is concerned with the impact of brain damage on task performance.
Cortex, 2003
It is claimed that task dissociations and, in particular, double dissociations constitute critica... more It is claimed that task dissociations and, in particular, double dissociations constitute critical evidence for the existence of separate mental functions, processes, or modules. As a result, considerable research effort has been directed towards discovering and cataloging them. This effort presupposes that experimental data can be unequivocally characterized as constituting either a dissociation or something else. I want to argue that it is impossible to make this distinction. Therefore it is impossible to use a dissociation to assert the existence of separate mental functions.
In this paper we outline a new approach to the study of language production. Central to this appr... more In this paper we outline a new approach to the study of language production. Central to this approach is the assumption that communication takes place in a dynamic environment in which cognitive resources are deployed to achieve 'Right-Time' as distinct from 'Fast-as-Possible' solutions. This is based on the assumption that language production includes a single, integrated, interactive process that recruits and coordinates information from a variety of internal, external and interactive sources to build each speech segment. The output of this process is reflected in the longer of the two log-normal pause duration distributions observed in spontaneous speech . The methodology described here permits the inspection of temporally defined processes under natural speaking conditions. The procedures do not rely on the assumption that language is the product of independent components that can be studied under static, de-contextualised conditions. Results from aphasia, amnesia and bilingualism will be used to illustrate the new paradigm.
Page 115. 7 Domain-Specific Resources in Word Recognition Kim Kirsner, John C. Dunn, and Peter St... more Page 115. 7 Domain-Specific Resources in Word Recognition Kim Kirsner, John C. Dunn, and Peter Standen University of Western Australia ABSTRACT Much remains to be discovered about the impact of specific types of experience and training on performance. ...
Australian Psychologist, 1997
Journal of Experimental Psychology: Learning, Memory, and Cognition, 2014
Journal of Memory and Language, 2006
Does recognition memory rely on discrete recollection, continuous evidence, or both? Is continuou... more Does recognition memory rely on discrete recollection, continuous evidence, or both? Is continuous evidence sensitive to only the recency and duration of study (familiarity), or is it also sensitive to details of the study episode? Dual process theories assume recognition is based on recollection and familiarity, with only recollection providing knowledge about study details. Single process theories assume a single continuous evidence dimension that can provide information about familiarity and details. We replicated list and plural discrimination experiments requiring knowledge of details to discriminate targets from similar non-targets. We also ran modified versions of these experiments aiming to increase recollection by removing non-targets that could be discriminated by familiarity alone. Single process models provided the best trade-off between goodness-of-fit and model complexity and dual process models were able to account for the data only when they incorporated continuous evidence sensitive to details.
Front Behav Neurosci, 2014
- The neural correlates of risk propensity in males and females using resting-state fMRI. Fro... more 2014) The neural correlates of risk propensity in males and females using resting-state fMRI. Front. Behav. Neurosci. 8:2.
Trends in Cognitive Sciences, 2008
Proceedings of the National Academy of Sciences, 1997
OspA (outer surface protein A) is an abundant immunogenic lipoprotein of the Lyme disease spiroch... more OspA (outer surface protein A) is an abundant immunogenic lipoprotein of the Lyme disease spirochete Borrelia burgdorferi. The crystal structure of a soluble recombinant form of OspA was solved in a complex with the Fab fragment of mouse monoclonal antibody 184.1 and refined to a resolution of 1.9 Å. OspA has a repetitive antiparallel  topology with an unusual nonglobular region of ''freestanding'' sheet connecting globular N-and C-terminal domains. Arrays of residues with alternating charges are a predominant feature of the folding pattern in the nonglobular region. The 184.1 epitope overlaps with a well conserved surface in the N-terminal domain, and a hydrophobic cavity buried in a positively charged cleft in the C-terminal domain is a potential binding site for an unknown ligand. An exposed variable region on the C-terminal domain of OspA is predicted to be an important factor in the worldwide effectiveness of OspA-based vaccines.
Proceedings of the National Academy of Sciences of the United States of America, Jan 22, 2015
Laboratory-based mock crime studies have often been interpreted to mean that (i) eyewitness confi... more Laboratory-based mock crime studies have often been interpreted to mean that (i) eyewitness confidence in an identification made from a lineup is a weak indicator of accuracy and (ii) sequential lineups are diagnostically superior to traditional simultaneous lineups. Largely as a result, juries are increasingly encouraged to disregard eyewitness confidence, and up to 30% of law enforcement agencies in the United States have adopted the sequential procedure. We conducted a field study of actual eyewitnesses who were assigned to simultaneous or sequential photo lineups in the Houston Police Department over a 1-y period. Identifications were made using a three-point confidence scale, and a signal detection model was used to analyze and interpret the results. Our findings suggest that (i) confidence in an eyewitness identification from a fair lineup is a highly reliable indicator of accuracy and (ii) if there is any difference in diagnostic accuracy between the two lineup formats, it li...
Scientific reports, 2015
People frequently change their preferences for options of gambles which they play once compared t... more People frequently change their preferences for options of gambles which they play once compared to those they play multiple times. In general, preferences for repeated play gambles are more consistent with the expected values of the options. According to the one-process view, the change in preference is due to a change in the structure of the gamble that is relevant to decision making. According to the two-process view, the change is attributable to a shift in the decision making strategy that is used. To adjudicate between these two theories, we asked participants to choose between gambles played once or 100 times, and to choose between them based on their expected value. Consistent with the two-process theory, we found a set of brain regions that were sensitive to the extent of behavioral change between single and aggregated play and also showed significant (de)activation in the expected value choice task. These results support the view that people change their decision making str...
Psychological Review, 2004
This article critically examines the view that the signal detection theory (SDT) interpretation o... more This article critically examines the view that the signal detection theory (SDT) interpretation of the remember-know (RK) paradigm has been ruled out by the evidence. The author evaluates 5 empirical arguments against a database of 72 studies reporting RK data under 400 different conditions. These arguments concern (a) the functional independence of remember and know rates, (b) the invariance of estimates of sensitivity, (c) the relationship between remember rates and overall hit and false alarm rates, (d) the relationship between RK responses and confidence judgments, and (e) dissociations between remember and overall hit rates. Each of these arguments is shown to be flawed, and despite being open to refutation, the SDT interpretation is consistent with existing data from both the RK and rememberknow-guess paradigms and offers a basis for further theoretical development.
Psychological Review, 2008
This article addresses the issue of whether the remember-know (RK) task is best explained by a si... more This article addresses the issue of whether the remember-know (RK) task is best explained by a single-process or a dual-process model. All single-process models propose that remember and know responses reflect different levels of a single strength-of-evidence dimension. Thus, across conditions in which response criteria are held constant, these models predict that the RK task is unidimensional. Many dual-process models propose that remember and know responses reflect two qualitatively distinct processes underlying recognition memory, often characterized as recollection and familiarity. These models predict that the RK task is bidimensional. Using data from 37 studies, the author conducted a state-trace analysis to determine the dimensionality of the RK task. In those studies, non-memory-related differences between conditions were eliminated via decision criteria constrained to be constant across all levels of the independent variables. The results reveal little or no evidence of bidimensionality and lend additional support to the unequal-variance signal detection model. Other arguments supporting a bidimensional interpretation are examined, and the author concludes there is insufficient evidence for the RK task to be used to identify qualitatively different memory components.
Psychological Review, 1988
Psychological Research Psychologische Forschung, 2000
A recent controversy in the ®eld of depth perception has highlighted an important aspect of model... more A recent controversy in the ®eld of depth perception has highlighted an important aspect of model testing concerning a model's complexity, de®ned as the prior propensity of the model to ®t arbitrary data sets. The present article introduces an index of complexity, called the mean minimum distance, de®ned as the average squared distance between an arbitrary data point and the prediction range of the model. It may also be expressed as a dimensionless quantity called the scaled mean minimum distance. For linear models, theoretical values for the scaled mean minimum distance and the variance of the scaled minimum distance can be readily obtained and compared against empirical estimates obtained from ®ts to random data. The approach is applied to resolving the question of the relative complexity of the Linear Integration model and the Fuzzy Logic of Perception model, both of which have been the subject of controversy in the ®eld of depth perception. It is concluded that the two models are equally complex.
Journal of Mathematical Psychology, 2003
Psychological constructs can only be measured indirectly in terms overt behavior, often by means ... more Psychological constructs can only be measured indirectly in terms overt behavior, often by means of changes in the level of performance on tasks they are presumed to affect. However, the exact relationship between constructs and the tasks they are presumed to affect is usually not known, which often requires non-essential auxiliary assumptions to be added to a psychological model to allow it to contact the data. Signed difference analysis is a method of deriving testable consequences from psychological models under the general assumption that the relationship between task performance and the constructs or combinations of constructs postulated by the model is at least monotonic. The predictions derived using signed difference analysis do not depend upon estimation of either model parameters or explicit functional relationships. In the present paper, the mathematical theory of signed difference analysis is presented and applied to illustrative problems drawn from research in memory, spatial attention, and reading. The relationships between signed difference analysis and related inferential procedures such as conjoint measurement, statetrace analysis, and double dissociation are discussed. r
Journal of Experimental Psychology: Learning, Memory, and Cognition, 2012
Evidence that learning rule-based (RB) and information-integration (II) category structures can b... more Evidence that learning rule-based (RB) and information-integration (II) category structures can be dissociated across different experimental variables has been used to support the view that such learning is supported by multiple learning systems. Across 4 experiments, we examined the effects of 2 variables, the delay between response and feedback and the informativeness of feedback, which had previously been shown to dissociate learning of the 2 types of category structure. Our aim was twofold: first, to determine whether these dissociations meet the more stringent inferential criteria of state-trace analysis and, second, to determine the conditions under which they can be observed. Experiment 1 confirmed that a mask-filled feedback delay dissociated the learning of RB and II category structures with minimally informative (yes/no) feedback and also met the state-trace criteria for the involvement of multiple latent variables. Experiment 2 showed that this effect is eliminated when a less similar, fixed pattern mask is presented in the interval between response and feedback. Experiment 3 showed that the selective effect of feedback delay on II learning is reduced with fully informative feedback (in which the correct category is specified after an incorrect response) and that feedback type did not dissociate RB and II learning. Experiment 4 extended the results of Experiment 2, showing that the differential effect of feedback delay is eliminated when a fixed pattern mask is used. These results pose important challenges to models of category learning, and we discuss their implications for multiple learning system models and their alternatives.
Journal of Clinical and Experimental Neuropsychology (Neuropsychology, Development and Cognition: Section A), 2002
The aim of this study was to compare traditional methods of scoring the Logical Memory test of th... more The aim of this study was to compare traditional methods of scoring the Logical Memory test of the Wechsler Memory Scale-III with a new method based on Latent Semantic Analysis (LSA). LSA represents texts as vectors in a high-dimensional semantic space and the similarity of any two texts is measured by the cosine of the angle between their respective vectors. The Logical Memory test was administered to a sample of 72 elderly individuals, 14 of whom were classi®ed as cognitively impaired by the Mini-Mental State Examination (MMSE). The results showed that LSA was at least as valid and sensitive as traditional measures. Partial correlations between prose recall measures and measures of cognitive function indicated that LSA explained all the relationship between Logical Memory and general cognitive function. This suggests that LSA may serve as an improved measure of prose recall.
Cortex, 2003
The joint aim of cognitive psychology and cognitive neuropsychology is to describe the functional... more The joint aim of cognitive psychology and cognitive neuropsychology is to describe the functional architecture of the human mind. That is, to identify, characterize, and enumerate the fundamental mental processes underlying human behaviour. In both of these fields, behaviour is measured in terms of performance on a wide range of tasks that are presumed to involve different combinations of mental functions. The two fields differ primarily in the nature of the conditions under which these tasks are performed. Specifically, whereas cognitive psychology generally involves systematic manipulation of variables in experiments involving non-brain damaged participants, cognitive neuropsychology is concerned with the impact of brain damage on task performance.
Cortex, 2003
It is claimed that task dissociations and, in particular, double dissociations constitute critica... more It is claimed that task dissociations and, in particular, double dissociations constitute critical evidence for the existence of separate mental functions, processes, or modules. As a result, considerable research effort has been directed towards discovering and cataloging them. This effort presupposes that experimental data can be unequivocally characterized as constituting either a dissociation or something else. I want to argue that it is impossible to make this distinction. Therefore it is impossible to use a dissociation to assert the existence of separate mental functions.
In this paper we outline a new approach to the study of language production. Central to this appr... more In this paper we outline a new approach to the study of language production. Central to this approach is the assumption that communication takes place in a dynamic environment in which cognitive resources are deployed to achieve 'Right-Time' as distinct from 'Fast-as-Possible' solutions. This is based on the assumption that language production includes a single, integrated, interactive process that recruits and coordinates information from a variety of internal, external and interactive sources to build each speech segment. The output of this process is reflected in the longer of the two log-normal pause duration distributions observed in spontaneous speech . The methodology described here permits the inspection of temporally defined processes under natural speaking conditions. The procedures do not rely on the assumption that language is the product of independent components that can be studied under static, de-contextualised conditions. Results from aphasia, amnesia and bilingualism will be used to illustrate the new paradigm.
Page 115. 7 Domain-Specific Resources in Word Recognition Kim Kirsner, John C. Dunn, and Peter St... more Page 115. 7 Domain-Specific Resources in Word Recognition Kim Kirsner, John C. Dunn, and Peter Standen University of Western Australia ABSTRACT Much remains to be discovered about the impact of specific types of experience and training on performance. ...
Australian Psychologist, 1997
Journal of Experimental Psychology: Learning, Memory, and Cognition, 2014
Journal of Memory and Language, 2006
Does recognition memory rely on discrete recollection, continuous evidence, or both? Is continuou... more Does recognition memory rely on discrete recollection, continuous evidence, or both? Is continuous evidence sensitive to only the recency and duration of study (familiarity), or is it also sensitive to details of the study episode? Dual process theories assume recognition is based on recollection and familiarity, with only recollection providing knowledge about study details. Single process theories assume a single continuous evidence dimension that can provide information about familiarity and details. We replicated list and plural discrimination experiments requiring knowledge of details to discriminate targets from similar non-targets. We also ran modified versions of these experiments aiming to increase recollection by removing non-targets that could be discriminated by familiarity alone. Single process models provided the best trade-off between goodness-of-fit and model complexity and dual process models were able to account for the data only when they incorporated continuous evidence sensitive to details.
Front Behav Neurosci, 2014
- The neural correlates of risk propensity in males and females using resting-state fMRI. Fro... more 2014) The neural correlates of risk propensity in males and females using resting-state fMRI. Front. Behav. Neurosci. 8:2.
Trends in Cognitive Sciences, 2008
Proceedings of the National Academy of Sciences, 1997
OspA (outer surface protein A) is an abundant immunogenic lipoprotein of the Lyme disease spiroch... more OspA (outer surface protein A) is an abundant immunogenic lipoprotein of the Lyme disease spirochete Borrelia burgdorferi. The crystal structure of a soluble recombinant form of OspA was solved in a complex with the Fab fragment of mouse monoclonal antibody 184.1 and refined to a resolution of 1.9 Å. OspA has a repetitive antiparallel  topology with an unusual nonglobular region of ''freestanding'' sheet connecting globular N-and C-terminal domains. Arrays of residues with alternating charges are a predominant feature of the folding pattern in the nonglobular region. The 184.1 epitope overlaps with a well conserved surface in the N-terminal domain, and a hydrophobic cavity buried in a positively charged cleft in the C-terminal domain is a potential binding site for an unknown ligand. An exposed variable region on the C-terminal domain of OspA is predicted to be an important factor in the worldwide effectiveness of OspA-based vaccines.