Neurons in the brain are seldom perfectly quiet. They continually receive input and generate outp... more Neurons in the brain are seldom perfectly quiet. They continually receive input and generate output, resulting in highly variable patterns of ongoing activity. Yet the functional significance of this variability is not well understood. If brain signal variability is functionally relevant and serves as an important indicator of cognitive function, then it should be highly sensitive to the precise manner in which a cognitive system is engaged and/or relate strongly to differences in behavioral performance. To test this, we examined EEG activity in younger adults as they performed a cognitive skill learning task and during rest. Several measures of EEG variability and signal strength were calculated in overlapping time windows that spanned the trial interval. We performed a systematic examination of the factors that most strongly influenced the variability and strength of EEG activity. First, we examined the relative sensitivity of each measure to across-subject variation (within blocks) and across-block variation (within subjects). We found that the across-subject variation in EEG variability and signal strength was much stronger than the across-block variation. Second, we examined the sensitivity of each measure to different sources of across-block variation during skill acquisition. We found that key task-driven changes in EEG activity were best reflected in changes in the strength, rather than the variability, of EEG activity. Lastly, we examined across-subject variation in each measure and its relationship with behavior. We found that individual differences in response time measures were best reflected in individual differences in the variability, rather than the strength, of EEG activity. Importantly, we found that individual differences in EEG variability related strongly to stable indicators of subject identity rather than dynamic indicators of subject performance. We therefore suggest that EEG variability may provide a more sensitive subject-driven measure of individual differences than task-driven signal of interest.
Canadian Journal of Experimental Psychology, Jun 1, 2009
When faced with a relatively novel task, it is reasonable to assume that increases in performance... more When faced with a relatively novel task, it is reasonable to assume that increases in performance efficiency depend upon processing adjustments that occur in response to errant or suboptimal performance. For such dynamic corrections to occur, the errors must first be noted, which can be challenging in contexts where no external feedback is provided. In the present article, the authors describe how a "double cross" error monitoring and correction process can be added to diffusion models of binary decision. The authors first outline the logick of our proposed error detection system, and then demonstrate that the addition of this double-cross process in the context of a simulation of lexical decision leads to more efficient responding. That is, with such a mechanism in place, the model was able to gradually respond more quickly and the distribution of errors became more consistent with human response patterns.
Journal of Computer Assisted Learning, Oct 27, 2008
As class sizes increase, methods of assessments shift from costly traditional approaches (e.g. ex... more As class sizes increase, methods of assessments shift from costly traditional approaches (e.g. expert-graded writing assignments) to more economic and logistically feasible methods (e.g. multiple-choice testing, computer-automated scoring, or peer assessment). While each method of assessment has its merits, it is peer assessment in particular, especially when made available online through a Web-based interface (e.g. our peerScholar system), that has the potential to allow a reintegration of open-ended writing assignments in any size class-and in a manner that is pedagogically superior to traditional approaches. Many benefits are associated with peer assessment, but it was the concerns that prompted two experimental studies (n = 120 in each) using peerScholar to examine mark agreement between and within groups of expert (graduate teaching assistants) and peer (undergraduate students) markers. Overall, using peerScholar accomplished the goal of returning writing into a large class, while producing grades similar in level and rank order as those provided by expert graders, especially when a grade accountability feature was used.
Journal of Experimental Psychology: General, May 1, 2020
Language comprehension is left-lateralized but with variable contributions from the right hemisph... more Language comprehension is left-lateralized but with variable contributions from the right hemisphere. When both hemispheres are stimulated simultaneously using divided visual field presentation, performance may be enhanced or hindered depending on the complexity of the task, and these effects may relate to independent processing in both hemispheres or to information transfer between hemispheres. Simultaneous stimulation of both hemispheres is thought to suppress interhemispheric interactions, but information transfer may nonetheless occur. Studies with simultaneous bilateral displays have demonstrated that semantic information from the contralateral visual field (and hemisphere) can facilitate relatedness judgments and lexical decisions. The current study extends this line of research by assessing semantic information transfer in a bilateral word identification task. Task manipulations involving directed spatial attention and asymmetric primes (e.g., ATOM → BOMB) were used to isolate automatic priming as opposed to top-down processing. The results revealed 2 main findings: (a) interhemispheric priming in the form of improved word recognition occurred specifically in conditions designed to isolate automatic transfer of semantic information, that is, in the attended visual field for the target word in asymmetric prime pairs, and (b) there is evidence for an asymmetrical transfer of semantic information, in that the subordinate left visual field-right hemisphere benefited more from such transfer. Together, these results demonstrate evidence for automatic interhemispheric transfer of semantic information, even under conditions of simultaneous bilateral display. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Archives of Clinical Neuropsychology, Sep 30, 2012
Poor effort by examinees during neuropsychological testing has a profound effect on test performa... more Poor effort by examinees during neuropsychological testing has a profound effect on test performance. Although neuropsychological experiments often utilize healthy undergraduate students, the test-taking effort of this population has not been investigated previously. The purpose of the present study was to determine whether undergraduate students exercise variable effort in neuropsychological testing. During two testing sessions, participants (N ¼ 36) were administered three Symptom Validity Tests (SVTs), the Test of Memory Malingering, the Dot Counting Test, and the Victoria Symptom Validity Test (VSVT), along with various neuropsychological tests. Analyses revealed 55.6% of participants in Session 1 and 30.8% of participants in Session 2 exerted poor effort on at least one SVT. Poor effort on the SVTs was significantly correlated with poor performance on various neuropsychological tests and there was support for the temporal stability of effort. These preliminary results suggest that the base rate of suboptimal effort in a healthy undergraduate population is quite high. Accordingly, effort may serve as a source of variance in neuropsychological research when using undergraduate students.
Journal of Experimental Psychology: Learning, Memory and Cognition, 2000
The authors use the qualitative differences logic to demonstrate that 2 separate memory influence... more The authors use the qualitative differences logic to demonstrate that 2 separate memory influences underlie performance in recognition memory tasks, familiarity and recollection. The experiments focus on the mirror effect, the finding that more memorable stimulus classes produce higher hit rates but lower false-alarm rates than less memorable stimulus classes. The authors demonstrate across a number of experiments that manipulations assumed to decrease recollection eliminate or even reverse the hit-rate portion of the mirror effect while leaving the false-alarm portion intact. This occurs whether the critical distinction between conditions is created during the test phase or manipulated during the study phase. Thus, when recollection is present, it dominates familiarity so that the hit-rate portion of the mirror effect primarily reflects recollection; when recollection is largely absent, the opposite pattern associated with the familiarity process emerges.
Journal of Experimental Psychology: Learning, Memory and Cognition, 1997
described a theory of priming that predicts long-term effects for all forms of relatedness. This ... more described a theory of priming that predicts long-term effects for all forms of relatedness. This prediction is reconciled with previous failures to observe long-term semantic priming on the basis of 2 claims: (a) that previously used pairs share few semantic features and (b) that tasks typically used to study priming are not especially sensitive to semantic influences. The present experiments provide further support for these claims by demonstrating long-term semantic priming in the lexical-decision task when the stimuli and task are modified in a way that increases semantic involvement. However, the findings suggest that in addition to the mechanism advocated by Becker et al., a second mechanism is necessary to provide a complete account of semantic priming effects. Meyer and Schvaneveldt (1971) introduced the lexicaldecision task as a tool for learning more about the processes and mechanisms underlying semantic memory. In its original form, the task consisted of two letter strings simultaneously presented, with participants instructed to press one key if both stimuli were words, and another key if one or both of the stimuli were nonwords. Findings from that task indicated that correct "word** responses could be emitted faster if the stimuli consisted of a pair of semantically related words (e.g., sky-cloud) than if the stimuli consisted of apair of semantically unrelated words (e.g., car-cloud). This phenomenon is called semantic priming. In follow-up work, Meyer, Schvaneveldt, and Ruddy (1972) discovered two other facts about semantic priming. The first was that the priming observed in the original study was also observed with a procedure in which participants had to judge the lexical status of a single item that either was or was not preceded by a semantically related associate. The second discovery was that the magnitude of the semantic priming effect was strongly affected if items were presented between the prime and target. In their experiment, they found that the strong semantic priming effect observed when the prime and target were presented consecutively became
Advances in early childhood and K-12 education, Jan 11, 2019
Online learning allows one to escape traditional constraints and to create learning experiences t... more Online learning allows one to escape traditional constraints and to create learning experiences that allow interactions, and support learning, that would be difficult or impossible in brick and mortar contexts. In this chapter, the authors present a new RIFS taxonomy (Relevance, Interestingness, Fun, and Sociality) to highlight the factors that can make a learning experience especially engaging. They then discuss what they want students to learn when they are engaged in support of 21 st century learning. With this context, they describe an initiative called The Global Teenager Project as a concrete example of how, with heavy support from online technologies, these factors can be combined to produce deep learning that students truly find meaningful.
Proceedings of the Annual Meeting of the Cognitive Science Society, 2009
We describe a theory of decision system adaptation in which yoked criteria shifts serve as a simp... more We describe a theory of decision system adaptation in which yoked criteria shifts serve as a simple but powerful mechanism for rapidly minimizing errors without sacrificing speed. To support our theory, we implemented a connectionist model of lexical decision, wherein the state of a word perception network was "read" by a pair of decision units. The response criteria for these decision units were then subjected to yoked shifts to examine how, in the face of perceived errors, such a response mechanism might adjust performance. We also present the results of a lexical decision experiment that manipulated the truthfulness of the feedback participants received so as to trigger the error correction mechanism while keeping other task parameters constant. The results of the experiment largely parallel those of the simulation, suggesting that yoked decision shifts make an important contribution to error minimization in decision system adaptation.
Canadian Journal of Experimental Psychology, Sep 1, 2013
We examine the relationship between a measure of intelligence and estimates of conscious and unco... more We examine the relationship between a measure of intelligence and estimates of conscious and unconscious memory influences derived using Jacoby's (Jacoby, L. L. [1991]. A process dissociation framework: Separating automatic from intentional uses of memory. Journal of Memory and Language, 30, 513-541.) process-dissociation procedure. We find a positive relationship between intelligence and conscious memory, and no relationship between intelligence and unconscious influences once the impact of conscious influences are removed (Experiment 1). We also find that when participants cannot engage in conscious strategies, such as when there is insufficient time for learning, the relationships observed in Experiment 1 are eliminated (Experiments 2A and 2B). Our results support the notion that individual differences in intelligence reflect differences in conscious strategic processes (
Neurons in the brain are seldom perfectly quiet. They continually receive input and generate outp... more Neurons in the brain are seldom perfectly quiet. They continually receive input and generate output, resulting in highly variable patterns of ongoing activity. Yet the functional significance of this variability is not well understood. If brain signal variability is functionally relevant and serves as an important indicator of cognitive function, then it should be highly sensitive to the precise manner in which a cognitive system is engaged and/or relate strongly to differences in behavioral performance. To test this, we examined EEG activity in younger adults as they performed a cognitive skill learning task and during rest. Several measures of EEG variability and signal strength were calculated in overlapping time windows that spanned the trial interval. We performed a systematic examination of the factors that most strongly influenced the variability and strength of EEG activity. First, we examined the relative sensitivity of each measure to across-subject variation (within blocks) and across-block variation (within subjects). We found that the across-subject variation in EEG variability and signal strength was much stronger than the across-block variation. Second, we examined the sensitivity of each measure to different sources of across-block variation during skill acquisition. We found that key task-driven changes in EEG activity were best reflected in changes in the strength, rather than the variability, of EEG activity. Lastly, we examined across-subject variation in each measure and its relationship with behavior. We found that individual differences in response time measures were best reflected in individual differences in the variability, rather than the strength, of EEG activity. Importantly, we found that individual differences in EEG variability related strongly to stable indicators of subject identity rather than dynamic indicators of subject performance. We therefore suggest that EEG variability may provide a more sensitive subject-driven measure of individual differences than task-driven signal of interest.
Canadian Journal of Experimental Psychology, Jun 1, 2009
When faced with a relatively novel task, it is reasonable to assume that increases in performance... more When faced with a relatively novel task, it is reasonable to assume that increases in performance efficiency depend upon processing adjustments that occur in response to errant or suboptimal performance. For such dynamic corrections to occur, the errors must first be noted, which can be challenging in contexts where no external feedback is provided. In the present article, the authors describe how a "double cross" error monitoring and correction process can be added to diffusion models of binary decision. The authors first outline the logick of our proposed error detection system, and then demonstrate that the addition of this double-cross process in the context of a simulation of lexical decision leads to more efficient responding. That is, with such a mechanism in place, the model was able to gradually respond more quickly and the distribution of errors became more consistent with human response patterns.
Journal of Computer Assisted Learning, Oct 27, 2008
As class sizes increase, methods of assessments shift from costly traditional approaches (e.g. ex... more As class sizes increase, methods of assessments shift from costly traditional approaches (e.g. expert-graded writing assignments) to more economic and logistically feasible methods (e.g. multiple-choice testing, computer-automated scoring, or peer assessment). While each method of assessment has its merits, it is peer assessment in particular, especially when made available online through a Web-based interface (e.g. our peerScholar system), that has the potential to allow a reintegration of open-ended writing assignments in any size class-and in a manner that is pedagogically superior to traditional approaches. Many benefits are associated with peer assessment, but it was the concerns that prompted two experimental studies (n = 120 in each) using peerScholar to examine mark agreement between and within groups of expert (graduate teaching assistants) and peer (undergraduate students) markers. Overall, using peerScholar accomplished the goal of returning writing into a large class, while producing grades similar in level and rank order as those provided by expert graders, especially when a grade accountability feature was used.
Journal of Experimental Psychology: General, May 1, 2020
Language comprehension is left-lateralized but with variable contributions from the right hemisph... more Language comprehension is left-lateralized but with variable contributions from the right hemisphere. When both hemispheres are stimulated simultaneously using divided visual field presentation, performance may be enhanced or hindered depending on the complexity of the task, and these effects may relate to independent processing in both hemispheres or to information transfer between hemispheres. Simultaneous stimulation of both hemispheres is thought to suppress interhemispheric interactions, but information transfer may nonetheless occur. Studies with simultaneous bilateral displays have demonstrated that semantic information from the contralateral visual field (and hemisphere) can facilitate relatedness judgments and lexical decisions. The current study extends this line of research by assessing semantic information transfer in a bilateral word identification task. Task manipulations involving directed spatial attention and asymmetric primes (e.g., ATOM → BOMB) were used to isolate automatic priming as opposed to top-down processing. The results revealed 2 main findings: (a) interhemispheric priming in the form of improved word recognition occurred specifically in conditions designed to isolate automatic transfer of semantic information, that is, in the attended visual field for the target word in asymmetric prime pairs, and (b) there is evidence for an asymmetrical transfer of semantic information, in that the subordinate left visual field-right hemisphere benefited more from such transfer. Together, these results demonstrate evidence for automatic interhemispheric transfer of semantic information, even under conditions of simultaneous bilateral display. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Archives of Clinical Neuropsychology, Sep 30, 2012
Poor effort by examinees during neuropsychological testing has a profound effect on test performa... more Poor effort by examinees during neuropsychological testing has a profound effect on test performance. Although neuropsychological experiments often utilize healthy undergraduate students, the test-taking effort of this population has not been investigated previously. The purpose of the present study was to determine whether undergraduate students exercise variable effort in neuropsychological testing. During two testing sessions, participants (N ¼ 36) were administered three Symptom Validity Tests (SVTs), the Test of Memory Malingering, the Dot Counting Test, and the Victoria Symptom Validity Test (VSVT), along with various neuropsychological tests. Analyses revealed 55.6% of participants in Session 1 and 30.8% of participants in Session 2 exerted poor effort on at least one SVT. Poor effort on the SVTs was significantly correlated with poor performance on various neuropsychological tests and there was support for the temporal stability of effort. These preliminary results suggest that the base rate of suboptimal effort in a healthy undergraduate population is quite high. Accordingly, effort may serve as a source of variance in neuropsychological research when using undergraduate students.
Journal of Experimental Psychology: Learning, Memory and Cognition, 2000
The authors use the qualitative differences logic to demonstrate that 2 separate memory influence... more The authors use the qualitative differences logic to demonstrate that 2 separate memory influences underlie performance in recognition memory tasks, familiarity and recollection. The experiments focus on the mirror effect, the finding that more memorable stimulus classes produce higher hit rates but lower false-alarm rates than less memorable stimulus classes. The authors demonstrate across a number of experiments that manipulations assumed to decrease recollection eliminate or even reverse the hit-rate portion of the mirror effect while leaving the false-alarm portion intact. This occurs whether the critical distinction between conditions is created during the test phase or manipulated during the study phase. Thus, when recollection is present, it dominates familiarity so that the hit-rate portion of the mirror effect primarily reflects recollection; when recollection is largely absent, the opposite pattern associated with the familiarity process emerges.
Journal of Experimental Psychology: Learning, Memory and Cognition, 1997
described a theory of priming that predicts long-term effects for all forms of relatedness. This ... more described a theory of priming that predicts long-term effects for all forms of relatedness. This prediction is reconciled with previous failures to observe long-term semantic priming on the basis of 2 claims: (a) that previously used pairs share few semantic features and (b) that tasks typically used to study priming are not especially sensitive to semantic influences. The present experiments provide further support for these claims by demonstrating long-term semantic priming in the lexical-decision task when the stimuli and task are modified in a way that increases semantic involvement. However, the findings suggest that in addition to the mechanism advocated by Becker et al., a second mechanism is necessary to provide a complete account of semantic priming effects. Meyer and Schvaneveldt (1971) introduced the lexicaldecision task as a tool for learning more about the processes and mechanisms underlying semantic memory. In its original form, the task consisted of two letter strings simultaneously presented, with participants instructed to press one key if both stimuli were words, and another key if one or both of the stimuli were nonwords. Findings from that task indicated that correct "word** responses could be emitted faster if the stimuli consisted of a pair of semantically related words (e.g., sky-cloud) than if the stimuli consisted of apair of semantically unrelated words (e.g., car-cloud). This phenomenon is called semantic priming. In follow-up work, Meyer, Schvaneveldt, and Ruddy (1972) discovered two other facts about semantic priming. The first was that the priming observed in the original study was also observed with a procedure in which participants had to judge the lexical status of a single item that either was or was not preceded by a semantically related associate. The second discovery was that the magnitude of the semantic priming effect was strongly affected if items were presented between the prime and target. In their experiment, they found that the strong semantic priming effect observed when the prime and target were presented consecutively became
Advances in early childhood and K-12 education, Jan 11, 2019
Online learning allows one to escape traditional constraints and to create learning experiences t... more Online learning allows one to escape traditional constraints and to create learning experiences that allow interactions, and support learning, that would be difficult or impossible in brick and mortar contexts. In this chapter, the authors present a new RIFS taxonomy (Relevance, Interestingness, Fun, and Sociality) to highlight the factors that can make a learning experience especially engaging. They then discuss what they want students to learn when they are engaged in support of 21 st century learning. With this context, they describe an initiative called The Global Teenager Project as a concrete example of how, with heavy support from online technologies, these factors can be combined to produce deep learning that students truly find meaningful.
Proceedings of the Annual Meeting of the Cognitive Science Society, 2009
We describe a theory of decision system adaptation in which yoked criteria shifts serve as a simp... more We describe a theory of decision system adaptation in which yoked criteria shifts serve as a simple but powerful mechanism for rapidly minimizing errors without sacrificing speed. To support our theory, we implemented a connectionist model of lexical decision, wherein the state of a word perception network was "read" by a pair of decision units. The response criteria for these decision units were then subjected to yoked shifts to examine how, in the face of perceived errors, such a response mechanism might adjust performance. We also present the results of a lexical decision experiment that manipulated the truthfulness of the feedback participants received so as to trigger the error correction mechanism while keeping other task parameters constant. The results of the experiment largely parallel those of the simulation, suggesting that yoked decision shifts make an important contribution to error minimization in decision system adaptation.
Canadian Journal of Experimental Psychology, Sep 1, 2013
We examine the relationship between a measure of intelligence and estimates of conscious and unco... more We examine the relationship between a measure of intelligence and estimates of conscious and unconscious memory influences derived using Jacoby's (Jacoby, L. L. [1991]. A process dissociation framework: Separating automatic from intentional uses of memory. Journal of Memory and Language, 30, 513-541.) process-dissociation procedure. We find a positive relationship between intelligence and conscious memory, and no relationship between intelligence and unconscious influences once the impact of conscious influences are removed (Experiment 1). We also find that when participants cannot engage in conscious strategies, such as when there is insufficient time for learning, the relationships observed in Experiment 1 are eliminated (Experiments 2A and 2B). Our results support the notion that individual differences in intelligence reflect differences in conscious strategic processes (
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