Matching Items (18)

The Role of Mediums in Distributed Learning

Description

The advancement of technology has transformed information consumption into an accessible and flexible process. The open learning ecosystem that exists online relies on self-direction. Learners are able to effectively fulfill

The advancement of technology has transformed information consumption into an accessible and flexible process. The open learning ecosystem that exists online relies on self-direction. Learners are able to effectively fulfill personal learning goals with preferred content forms, specifically by utilizing Massive Open Online Courses (MOOC). It is essential to investigate the role of mediums in distributed learning to initiate human-centric design changes that best support the learner. This study provides insight into how choice influences self-learning and highlights the major engagement difficulties of MOOCs. Significant attrition was experienced while issuing text and audio material to participants for three weeks. Although this prevented valid statistical tests from being run, it was clear that text was the most desirable and effective medium. Students that read exhibited the highest comprehension levels and selected it as their de-facto consumption method even if audio was made available. Since this study involved complex topics, this supported the transient information effect. Future studies should focus deeply on the structure of online courses by implementing personable engagement features that improve overall participation rate.

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Date Created
  • 2019

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Chronic unpredictable intermittent restraint stress disrupts hippocampal-dependent spatial memory in male, but not female rats

Description

The present series of studies examined whether a novel implementation of an

intermittent restraint (IR) chronic stress paradigm could be used to investigate hippocampal-dependent spatial ability in both sexes. In experiments

The present series of studies examined whether a novel implementation of an

intermittent restraint (IR) chronic stress paradigm could be used to investigate hippocampal-dependent spatial ability in both sexes. In experiments 1 and 2, Sprague- Dawley male rats were used to identify the optimal IR parameters to assess spatial ability. For IR, rats were restrained for 2 or 6hrs/day (IR2, IR6, respectively) for five days and then given two days off, a process that was repeated for three weeks and compared to rats restrained for 6hrs/d for each day (DR6) and non-stressed controls (CON). Spatial memory was tested on the radial arm water maze (RAWM), object placement (OP), novel object recognition (NOR) and Y-maze. The results for the first two experiments revealed that IR6, but not IR2, was effective in impairing spatial memory in male rats and that task order impacted performance. In experiment 3, an extended IR paradigm for six weeks was implemented before spatial memory testing commenced in male and female rats (IR- M, IR-F). Unexpectedly, an extended IR paradigm failed to impair spatial memory in either males or females, suggesting that when extended, the IR paradigm may have become predictable. In experiment 4, an unpredictable IR (UIR) paradigm was implemented, in which restraint duration (30 or 60-min) combined with orbital shaking, time of day, and the days off from UIR were varied. UIR impaired spatial memory in males, but not females. Together with other reports, these findings support the interpretation that chronic stress negatively impairs hippocampal-dependent function in males, but not females, and that females appear to be resilient to spatial memory deficits in the face of chronic stress.

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Date Created
  • 2019

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Reward-based sensorimotor decision making

Description

Existing theories suggest that evidence is accumulated before making a decision with competing goals. In motor tasks, reward and motor costs have been shown to influence the decision, but the

Existing theories suggest that evidence is accumulated before making a decision with competing goals. In motor tasks, reward and motor costs have been shown to influence the decision, but the interaction between these two variables has not been studied in depth. A novel reward-based sensorimotor decision-making task was developed to investigate how reward and motor costs interact to influence decisions. In human subjects, two targets of varying size and reward were presented. After a series of three tones, subjects initiated a movement as one of the targets disappeared. Reward was awarded when participants reached through the remaining target within a specific amount of time. Subjects had to initiate a movement before they knew which target remained. Reward was found to be the only factor that influenced the initial reach. When reward was increased, there was a lower probability of intermediate movements. Both target size and reward lowered reaction times individually and jointly. This interaction can be interpreted as the effect of the expected value, which suggests that reward and target size are not evaluated independently during motor planning. Curvature, or the changing of motor plans, was driven primarily by the target size. After an initial decision was made, the motor costs to switch plans and hit the target had the largest impact on the curvature. An interaction between the reward and target size was also found for curvature, suggesting that the expected value of the target influences the changing of motor plans. Reward, target size, and the interaction between the two were all significant factors for different parts of the decision-making process.

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Date Created
  • 2019

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Is the Click the Trick? The Efficacy of Clickers and Other Reinforcement Methods in Training Naïve Dogs to Perform New Tasks

Description

A handheld metal noisemaker known as a “clicker” is widely used to train new behaviors in dogs; however, evidence for the superior efficacy of clickers as opposed to providing solely

A handheld metal noisemaker known as a “clicker” is widely used to train new behaviors in dogs; however, evidence for the superior efficacy of clickers as opposed to providing solely primary reinforcement or other secondary reinforcers in the acquisition of novel behavior in dogs is almost entirely anecdotal. Three experiments were conducted to determine under what circumstances a clicker may result in acquisition of a novel behavior more rapidly or to a higher level compared to other readily available reinforcement methods. In Experiment 1, three groups of 30 dogs each were trained to emit a novel sit and stay behavior of increasing duration with either the delivery of food alone, a verbal stimulus paired with food, or a clicker with food. The group that received only a primary reinforcer reached a significantly higher criterion of training success than the group trained with a verbal secondary reinforcer. Performance of the group experiencing a clicker secondary reinforcer was intermediate between the other two groups, but not significantly different from either. In Experiment 2, three different groups of 25 dogs each were shaped to emit a nose targeting behavior and then perform that behavior at increasing distances from the experimenter using the same three methods of positive reinforcement as in Experiment 1. No statistically significant differences between the groups were found. In Experiment 3, three groups of 30 dogs each were shaped to emit a nose-targeting behavior upon an array of wooden blocks with task difficulty increasing throughout testing using the same three methods of positive reinforcement as previously. No statistically significant differences between the groups were found. Overall, the findings suggest that both clickers and other forms of positive reinforcement can be used successfully in training a dog to perform a novel behavior, but that no positive reinforcement method has significantly greater efficacy than any other.

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Date Created
  • 2020

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Cognitive changes across the menopause transition: a longitudinal evaluation of the impact of age and ovarian status on spatial memory

Description

Aging and the menopause transition are both intricately linked to cognitive changes

during mid-life and beyond. Clinical literature suggests the age at menopause onset can differentially impact cognitive status later in

Aging and the menopause transition are both intricately linked to cognitive changes

during mid-life and beyond. Clinical literature suggests the age at menopause onset can differentially impact cognitive status later in life. Yet, little is known about the relationship between behavioral and brain changes that occur during the transitional stage into the post-menopausal state. Much of the pre-clinical work evaluating an animal model of menopause involves ovariectomy in rodents; however, ovariectomy results in an abrupt loss of circulating hormones and ovarian tissue, limiting the ability to evaluate gradual follicular depletion. The 4-vinylcyclohexene diepoxide (VCD) model simulates transitional menopause in rodents by selectively depleting the immature ovarian follicle reserve and allowing animals to retain their follicle-deplete ovarian tissue, resulting in a profile similar to the majority of menopausal women. Here, Vehicle or VCD treatment was administered to ovary-intact adult and middle-aged Fischer-344 rats to assess the cognitive effects of transitional menopause via VCD-induced follicular depletion over time, as well as to understand potential interactions with age, with VCD treatment beginning at either six or twelve months of age. Results indicated that subjects that experience menopause onset at a younger age had impaired spatial working memory early in the transition to a follicle-deplete state. Moreover, in the mid- and post- menopause time points, VCD-induced follicular depletion amplified an age effect, whereby Middle-Aged VCD-treated animals had poorer spatial working and reference memory performance than Young VCD-treated animals. Correlations suggested that in middle age, animals with higher circulating estrogen levels tended to perform better on spatial memory tasks. Overall, these findings suggest that the age at menopause onset is a critical parameter to consider when evaluating learning and memory across the transition to reproductive senescence. From a translational perspective, this study informs the field with respect to how the age at menopause onset might impact cognition in menopausal women, as well as provides insight into time points to explore for the window of opportunity for hormone therapy during the menopause transition to attenuate age- and menopause- related cognitive decline, and produce healthy brain aging profiles in women who retain their ovaries throughout the lifespan.

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Date Created
  • 2015

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Interval timing under a behavioral microscope: dissociating motivational and timing processes in fixed-interval performance

Description

Theories of interval timing have largely focused on accounting for the aggregate properties of behavior engendered by periodic reinforcement, such as sigmoidal psychophysical functions and their scalar property. Many theories

Theories of interval timing have largely focused on accounting for the aggregate properties of behavior engendered by periodic reinforcement, such as sigmoidal psychophysical functions and their scalar property. Many theories of timing also stipulate that timing and motivation are inseparable processes. Such a claim is challenged by fluctuations in and out of states of schedule control, making it unclear whether motivation directly affects states related to timing. The present paper seeks to advance our understanding of timing performance by analyzing and comparing the distribution of latencies and inter-response times (IRTs) of rats in two fixed-interval (FI) schedules of food reinforcement (FI 30-s and FI 90-s), and in two levels of food deprivation. Computational modeling revealed that each component was well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies are sensitive to the periodicity of reinforcement, and pre-feeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Pre-feeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, these models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance, which need to be accounted for by causal theories of interval timing.

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Date Created
  • 2015

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Factors of religiosity and loss aversion

Description

Loss aversion manifests as a decision bias in which avoiding losses is preferred over acquiring rewards and can drastically alter an individual’s decision-making by overweighting potential losses relative to gains

Loss aversion manifests as a decision bias in which avoiding losses is preferred over acquiring rewards and can drastically alter an individual’s decision-making by overweighting potential losses relative to gains of equal magnitude. Consequently, individuals may require greater positive compensation to offset potential losses, exhibit contradictory choice preferences, or even avoid the decision entirely; and this behavior may be ascribed to an over-reliance on automatic, unconscious (intuitive) judgments rather than initiating analytic reasoning more capable of objectively evaluating outcomes.

Religion (specifically Christianity) is the topic of focus, as preliminary evidence suggests an individual’s intuitive inclinations positively correlate with and predict religious beliefs. Moreover, self-reported religious beliefs significantly differed as a function of inducing either intuitive or reflective mindsets. Therefore, the purpose of this experiment was to test the hypothesis that religious participants will display significantly greater levels of loss aversion than nonreligious participants.

This hypothesis extends from a previous study relating large-scale cultural and religious differences with loss aversion. While their results revealed religious orthodoxy strongly influenced loss aversion, the parameters elicited may be less stable as only two lottery questions were asked and religion was determined by cultural demographics. This study used the same design, but with a total of ten lotteries and a more detailed investigation into individual religious factors.

While loss aversion coefficients replicated the overall behavioral effect (Median θ = 2.6), independent sample, Mann-Whitney U tests did not yield any significant differences between Christian and Nonreligious participants (p > 0.05); nor did any of the religious factors examined account for a significant amount of variability.

This study attempted to add to current knowledge by further conflating the relationship between religiosity and adaptive decision strategies susceptible to errant and inconsistent behavior. While the hypotheses were unsupported, a null finding is still important, and future research re-testing this association or introducing causational designs may prove more fruitful in understanding these complex relationships.

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Date Created
  • 2017

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Mechanisms of recovery from chronic stress

Description

Chronic stress results in functional and structural changes to the hippocampus. Decades of research has led to insights into the mechanisms underlying the chronic stress-induced deficits in hippocampal-mediated cognition and

Chronic stress results in functional and structural changes to the hippocampus. Decades of research has led to insights into the mechanisms underlying the chronic stress-induced deficits in hippocampal-mediated cognition and reduction of dendritic complexity of hippocampal neurons. Recently, a considerable focus of chronic stress research has investigated the mechanisms behind the improvements in hippocampal mediated cognition when chronic stress ends and a post-stress rest period is given. Consequently, the goal of this dissertation is to uncover the mechanisms that allow for spatial ability to improve in the aftermath of chronic stress. In chapter 2, the protein brain derived neurotrophic factor (BDNF) was investigated as a mechanism that allows for spatial ability to show improvements following the end of chronic stress. It was found that decreasing the expression of BDNF in the hippocampus prevented spatial memory improvements following a post-stress rest period. Chapter 3 was performed to determine whether hippocampal CA3 apical dendritic complexity requires BDNF to show improvements following a post-stress rest period, and whether a receptor for BDNF, TrkB, mediates the improvements of spatial ability and dendritic complexity in a temporal manner, i.e. during the rest period only. These experiments showed that decreased hippocampal BDNF expression prevented improvements in dendritic complexity, and administration of a TrkB antagonist during the rest period also prevented the improvements in spatial ability and dendritic complexity. In chapter 4, the role of the GABAergic system on spatial ability following chronic stress and a post-stress rest period was investigated. Following chronic stress, it was found that male rats showed impairments on the acquisition phase of the RAWM and this correlated with limbic glutamic acid decarboxylase, a marker for GABA. In chapter 5, a transgenic mouse that expresses a permanent marker on all GABAergic interneurons was used to assess the effects of chronic stress and a post-stress rest period on hippocampal GABAergic neurons. While no changes were found on the total number of GABAergic interneurons, specific subtypes of GABAergic interneurons were affected by stressor manipulations. Collectively, these studies reveal some mechanisms behind the plasticity seen in the hippocampus in response to a post-stress rest period.

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Date Created
  • 2018

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A comparison of Los Angeles and Phoenix homeowners' attitudes and behaviors towards outdoor water conservation

Description

Los Angeles, California and Phoenix, Arizona are two naturally water-scarce regions that rely on imported water to meet their local water needs. Both areas have been experiencing an ongoing drought

Los Angeles, California and Phoenix, Arizona are two naturally water-scarce regions that rely on imported water to meet their local water needs. Both areas have been experiencing an ongoing drought that has negatively affected their local water supply. Populations in both cities continue to grow, increasing overall demand for water as the supply decreases. Water conservation is important for the sustainability of each town. However, the methods utilized to conserve residential water in the two areas differ drastically; Los Angeles has implemented involuntary water rationing and Phoenix has not.

The widespread effectiveness of involuntary restrictions makes them a popular management scheme. Despite their immediate effectiveness, little is known about how involuntary restrictions affect attitudinal precursors towards the behavior in question and thus, whether or not the restrictions are potentially helpful or harmful to lasting behavior change. This study adapted the Theory of Planned Behavior to survey 361 homeowners in Los Angeles and Phoenix to examine how involuntary water restrictions shape attitudinal precursors to outdoor water conservation.

This study found that when involuntary water restrictions are present, residents feel less in control of their outdoor water use. However, in the presence of involuntary water restrictions, stronger social norms and stronger support for policy prescriptions over outdoor water use were found. The favorable societal support towards water conservation, conceptualized as social norms and policy attitudes, in the presence of involuntary water restrictions is potentially promising for lasting behavior change.

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Date Created
  • 2016

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Improved Discrimination Between Tone and Context During Fear Extinction in Chronically Stressed Rats Provided with a Post-Stress Rest Period

Description

The goal of the present study was to investigate whether a rest period following the end of chronic stress would impact fear extinction. Past research has indicated that chronic

The goal of the present study was to investigate whether a rest period following the end of chronic stress would impact fear extinction. Past research has indicated that chronic stress leads to impairments in the learning and recall of fear conditioning extinction. Moreover, the effects of chronic stress can return to levels similar to controls when a post-stress “rest” period (i.e., undisturbed except for normal husbandry) is given prior to testing. Male rats underwent chronic restraint stress for 6hr/day/21days (STR-IMM). Some rats, underwent a post-stress rest period for 6- or 3-weeks after the end of stress (STR-R6, STR-R3). Control (CON) rats were unrestrained for the duration of the experiment. In Experiment 1, following the stress or rest manipulation, all rats were acclimated to conditioning and extinction contexts, fear conditioned with 3 tone-foot shock pairings, and then had two days of extinction training. All groups froze similarly to the tone across all training sessions. However, STR-R6/R3 froze less in the non-shock context than did STR-IMM or CON. During extinction training, STR-IMM showed high levels of freezing to the non-shock context, leading to a concern they may be generalizing across contexts. Consequently, a follow-up experiment tested for context generalization. In Experiment 2, STR-IMM rats underwent a generalization test in an environment that was either different or the same as the conditioning environment, using STR-R6 as a comparison. STR-IMM and STR-R6 showed similar relative levels of freezing to tone and context, regardless of their conditioning environment to reveal that STR-IMM did not generalize and instead, maybe expressing hypervigilance. Thus, the present study demonstrated the novel finding that a rest period from chronic stress can lead to reduced fear responsiveness in a non-shock environment.

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Date Created
  • 2018