Matching Items (12)

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Source memory revealed through eye movements and pupil dilation

Description

Current theoretical debate, crossing the bounds of memory theory and mental imagery, surrounds the role of eye movements in successful encoding and retrieval. Although the eyes have been shown to

Current theoretical debate, crossing the bounds of memory theory and mental imagery, surrounds the role of eye movements in successful encoding and retrieval. Although the eyes have been shown to revisit previously-viewed locations during retrieval, the functional role of these saccades is not known. Understanding the potential role of eye movements may help address classic questions in recognition memory. Specifically, are episodic traces rich and detailed, characterized by a single strength-driven recognition process, or are they better described by two separate processes, one for vague information and one for the retrieval of detail? Three experiments are reported, in which participants encoded audio-visual information while completing controlled patterns of eye movements. By presenting information in four sources (i.e., voices), assessments of specific and partial source memory were measured at retrieval. Across experiments, participants' eye movements at test were manipulated. Experiment 1 allowed free viewing, Experiment 2 required externally-cued fixations to previously-relevant (or irrelevant) screen locations, and Experiment 3 required externally-cued new or familiar oculomotor patterns to multiple screen locations in succession. Although eye movements were spontaneously reinstated when gaze was unconstrained during retrieval (Experiment 1), externally-cueing participants to re-engage in fixations or oculomotor patterns from encoding (Experiments 2 and 3) did not enhance retrieval. Across all experiments, participants' memories were well-described by signal-detection models of memory. Source retrieval was characterized by a continuous process, with evidence that source retrieval occurred following item memory failures, and additional evidence that participants partially recollected source, in the absence of specific item retrieval. Pupillometry provided an unbiased metric by which to compute receiver operating characteristic (ROC) curves, which were consistently curvilinear (but linear in z-space), supporting signal-detection predictions over those from dual-process theories. Implications for theoretical views of memory representations are discussed.

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Created

Date Created
  • 2012

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I Can’t Stand Thinking Anymore: An Analysis of Directed Attention on Posture

Description

Maintaining upright balance and postural control is a task that most individuals perform everyday with ease and without much thought. Although it may be a relatively easy task to

Maintaining upright balance and postural control is a task that most individuals perform everyday with ease and without much thought. Although it may be a relatively easy task to perform, research has shown that changes in cognitive (or “attentional”) processes are reflected in the movements of sway. The purpose of this dissertation is to understand the relationship between attention and posture when attention is directly or indirectly shifted away from posture. Using a dual-task paradigm, attention was shifted directly by instructing participants to prioritize the balance task (minimize sway in a unipedal stance) or prioritize the cognitive task (minimize errors in an auditory n-back task) and indirectly by changing the difficulty level of the cognitive task (0-back vs. 2-back task). Postural sway was assessed using sample entropy (SampEn), standard deviation, (SD) and sway path (SP) of trunk movements to measure the regularity, variability, and overall distance of sway travelled, respectively. Dual-task behavior was examined when participants were in a controlled (i.e., non-fatigued) state (Experiment 1), in a state of physical fatigue (Experiment 2), and in a state of mental fatigue (Experiment 3). Across all three experiments, indirectly shifting attention away from posture in the more difficult 2-back task induced less regularity (higher SampEn) and variability (smaller SD) in postural sway. Directly shifting attention away from posture, by prioritizing the cognitive task, induced less regularity (higher SampEn) and a longer path length (higher SP) in Experiment 1, however this effect was not significant for the fatigued participants in Experiments 2 and 3. Neither physical fatigue (Experiment 2) or mental fatigue (Experiment 3) negatively affected postural sway or cognitive performance. Overall, the findings from this dissertation contribute to the relationship between movement regularity and attention in posture, and that the postural behavior that emerges is sensitive to methods in which attention is manipulated (direct, indirect) and fatigue (physical, mental).

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Created

Date Created
  • 2019

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Regulating working memory In emotionally-laden contexts

Description

Individual differences in working memory capacity partly arise from variability in attention control, a process influenced by negative emotional content. Thus, individual differences in working memory capacity should be predictive

Individual differences in working memory capacity partly arise from variability in attention control, a process influenced by negative emotional content. Thus, individual differences in working memory capacity should be predictive of differences in the ability to regulate attention in emotional contexts. To address this hypothesis, a complex-span working memory task (symmetry span) was modified so that negative arousing images or neutral images subtended the background during the encoding phase. Across three experiments, negative arousing images impaired working memory encoding relative to neutral images, resulting in impoverished symmetry span scores. Additionally, in Experiment 3, both negative and arousing images captured attention and led to increased hit rates in a subsequent recognition task. Contrary to the primary hypothesis, individual differences in working memory capacity derived from three complex span tasks failed to moderate the effect of negative arousing images on working memory encoding across two large scale studies. Implications for theories of working memory and attention control in emotional contexts will be discussed.

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Created

Date Created
  • 2015

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Cognitive control processes underlying continuous and transient monitoring processes in event-based prospective memory

Description

A converging operations approach using response time distribution modeling was adopted to better characterize the cognitive control dynamics underlying ongoing task cost and cue detection in event based prospective memory

A converging operations approach using response time distribution modeling was adopted to better characterize the cognitive control dynamics underlying ongoing task cost and cue detection in event based prospective memory (PM). In Experiment 1, individual differences analyses revealed that working memory capacity uniquely predicted nonfocal cue detection, while proactive control and inhibition predicted variation in ongoing task cost of the ex-Gaussian parameter associated with continuous monitoring strategies (mu). In Experiments 2A and 2B, quasi-experimental techniques aimed at identifying the role of proactive control abilities in PM monitoring and cue detection suggested that low ability participants may have PM deficits during demanding tasks due to inefficient monitoring strategies, but that emphasizing importance of the intention can increase reliance on more efficacious monitoring strategies that boosts performance (Experiment 2A). Furthermore, high proactive control ability participants are able to efficiently regulate their monitoring strategies under scenarios that do not require costly monitoring for successful cue detection (Experiment 2B). In Experiments 3A and 3B, it was found that proactive control benefited cue detection in interference-rich environments, but the neural correlates of cue detection or intention execution did not differ when engaged in proactive versus reactive control. The results from the current set of studies highlight the importance of response time distribution modeling in understanding PM cost. Additionally, these results have important implications for extant theories of PM and have considerable applied ramifications concerning the cognitive control processes that should be targeted to improve PM abilities.

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Created

Date Created
  • 2015

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Action, Prediction, or Attention: Does the “Egocentric Temporal Order Bias” Support a Constructive Model of Perception?

Description

Temporal-order judgments can require integration of self-generated action-events and external sensory information. In a previous study, it was found that participants are biased to perceive one’s own action-events to occur

Temporal-order judgments can require integration of self-generated action-events and external sensory information. In a previous study, it was found that participants are biased to perceive one’s own action-events to occur prior to simultaneous external events. This phenomenon, named the “Egocentric Temporal Order Bias”, or ETO bias, was demonstrated as a 67% probability for participants to report self-generated events as occurring prior to simultaneous externally-determined events. These results were interpreted as supporting a feed-forward, constructive model of perception. However, the empirical data could support many potential mechanisms. The present study tests whether the ETO bias is driven by attentional differences, feed-forward predictability, or action. These findings support that participants exhibit a bias due to both feed-forward predictability and action, and a Bayesian analysis supports that these effects are quantitatively unique. Therefore, the results indicate that the ETO bias is largely driven by one’s own action, over and above feed-forward predictability.

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Created

Date Created
  • 2020

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Decoding the ERP/Behavior Link: A Trial-Level Approach to the NoGo-N200 Component

Description

In most of the work using event-related potentials (ERPs), researchers presume the function of specific components based on the careful manipulation of experimental factors, but rarely report direct evidence supporting

In most of the work using event-related potentials (ERPs), researchers presume the function of specific components based on the careful manipulation of experimental factors, but rarely report direct evidence supporting a relationship between the neural signal and other outcomes. Perhaps most troubling is the lack of evidence that ERPs correlate with related behavioral outcomes which should result, at least in part, from the neural processes that ERPs capture. One such example is the NoGo-N2 component, an ERP component elicited in Go/NoGo paradigms. There are two primary theories regarding the functional significance of this component in this context: that the signal represents response inhibition and that the component reflects conflict. In this paper, a trial-level method of analysis for the relationship between ERP component potentials and downstream behavioral outcomes (in this case, response accuracy) using a multi-level modeling framework is proposed to provide discriminatory evidence for one of these theories. Following a description of the research on the NoGo-N2, preliminary data supporting the conflict monitoring theory are presented, noting important limitations. Next, an EEG simulation study is presented in which NoGo-N2 data are generated with a known relationship to fabricated reaction time data, showing that, with added levels of complexity and noise within the data, the MLM approach is consistently successful at extracting the known relationships that occur in real NoGo-N2 data. Next, using independent components analysis (ICA) to extract spatiotemporal components that best represent the signal of interest, a well-powered analysis of the relationship between the NoGo-N2 and response accuracy is used to provide strong discriminatory evidence for the conflict monitoring theory of the NoGo-N2. Finally, implications for the NoGo-N2, as well as all ERP components, are discussed with a focus on how this approach can and should be used. the paper concludes with potential expansions of this approach to areas beyond identifying the function of ERP components.

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Agent

Created

Date Created
  • 2019

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Heaviness perception dynamics in the leg and arm

Description

Perceived heaviness of lifted objects has been shown to scale to a ratio of muscle activity and movement during elbow lifts. This scaling reflects the importance of the forces

Perceived heaviness of lifted objects has been shown to scale to a ratio of muscle activity and movement during elbow lifts. This scaling reflects the importance of the forces applied to an object and the resulting kinematics for this perception. The current study determined whether these perceived heaviness dynamics are similar in other lifting conditions. Anatomically sourced context-conditioned variability has implications for motor control. The current study investigated whether these implications also hold for heaviness perception. In two experiments participants lifted objects with knee extension lifts and with several arm lifts and reported perceived heaviness. The resulting psychophysiological functions revealed the hypothesized muscle activity and movement ratio in both leg and arms lifts. Further, principal component regressions showed that the forearm flexors and corresponding joint angular accelerations were most relevant for perceived heaviness during arm lifts. Perceived heaviness dynamics are similar in the arms and legs.

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Agent

Created

Date Created
  • 2016

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The recall dynamics of importance in delayed free recall

Description

An emerging literature on the relation between memory and importance has shown that people are able to selectively remember information that is more, relative to less important. Researchers in this

An emerging literature on the relation between memory and importance has shown that people are able to selectively remember information that is more, relative to less important. Researchers in this field have operationalized importance by assigning value to the different information that participants are asked to study and remember. In the present investigation I developed two experiments, using a slightly altered value-directed-remembering (VDR) paradigm, to investigate whether and how value modifies the dynamics of memory organization and search. Moreover, I asked participants to perform a surprise final free recall task in order to examine the effects of value in the recall dynamics of final free recall. In Experiment 1, I compared the recall dynamics of delayed and final free recall between a control and a value condition, in the latter of which numbers appeared next to words, in random order, denoting the value of remembering each word during recall. In Experiment 2, I manipulated the order of presentation of the values by adding an ascending and a descending condition where values were presented in either an ascending or a descending order, respectively. Overall, my results indicated that value affected several measures of delayed and final free recall, without, in most cases, taking away the serial position effects on those same measures.

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Created

Date Created
  • 2015

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The cognitive underpinnings of multiply-constrained problem solving

Description

In the daily life of an individual problems of varying difficulty are encountered.

Each problem may include a different number of constraints placed upon the problem

solver. One type of problem commonly

In the daily life of an individual problems of varying difficulty are encountered.

Each problem may include a different number of constraints placed upon the problem

solver. One type of problem commonly used in research are multiply-constrained

problems, such as the compound remote associates. Since their development they have

been related to creativity and insight. Moreover, research has been conducted to

determine the cognitive abilities underlying problem solving abilities. We sought to fully

evaluate the range of cognitive abilities (i.e., working memory, episodic and semantic

memory, and fluid and crystallized intelligence) linked to multiply-constrained problem

solving. Additionally, we sought to determine whether problem solving ability and

strategies (analytical or insightful) were task specific or domain general through the use

of novel problem solving tasks (TriBond and Location Bond). Results indicated that

multiply-constrained problem solving abilities were domain general, solutions derived

through insightful strategies were more often correct than analytical, and crystallized

intelligence was the only cognitive ability that provided unique predictive value.

Contributors

Agent

Created

Date Created
  • 2019

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A Mechanistic Account of the Relation between Working Memory Capacity and Fluid Intelligence

Description

Working memory capacity and fluid intelligence are important predictors of performance in educational settings. Thus, understanding the processes underlying the relation between working memory capacity and fluid intelligence is important.

Working memory capacity and fluid intelligence are important predictors of performance in educational settings. Thus, understanding the processes underlying the relation between working memory capacity and fluid intelligence is important. Three large scale individual differences experiments were conducted to determine the mechanisms underlying the relation between working memory capacity and fluid intelligence. Experiments 1 and 2 were designed to assess whether individual differences in strategic behavior contribute to the variance shared between working memory capacity and fluid intelligence. In Experiment 3, competing theories for describing the underlying processes (cognitive vs. strategy) were evaluated in a comprehensive examination of potential underlying mechanisms. These data help inform existing theories about the mechanisms underlying the relation between WMC and gF. However, these data also indicate that the current theoretical model of the shared variance between WMC and gF would need to be revised to account for the data in Experiment 3. Possible sources of misfit are considered in the discussion along with a consideration of the theoretical implications of observing those relations in the Experiment 3 data.

Contributors

Agent

Created

Date Created
  • 2018