Matching Items (7)

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Immediacy Premium: A Linear Estimator of Hyperbolic Delay Discounting Rate (k).

Description

The estimation of delay discounting rates (k) typically assume that the relative subjective value of a reinforcer declines as a reciprocal function of its delay. Despite the prevalence, estimates of

The estimation of delay discounting rates (k) typically assume that the relative subjective value of a reinforcer declines as a reciprocal function of its delay. Despite the prevalence, estimates of k based on least-squares fits of relative subjective value to the hyperbolic discount function appear to have serious limitations. This curve-fitting method provides curves, which when averaged, may not accurately reflect the individual subjects’ data. The present study used the hyperbolic discounting function to derive a new dependent measure, termed immediacy premium, which is a linear function of delay. By averaging linear rather than reciprocal functions, the averaged data are more representative of individual data, and comparisons between mean data across treatments or samples is more meaningful. Based on data published, the assumptions of least-square based estimates were evaluated for estimation methods based on relative subjective value and immediacy premiums. This analysis yielded mixed support for each method, thus advising for the implementation of both methods when drawing inferences on treatment effects and population differences.

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Agent

Created

Date Created
  • 2019-05

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Depletion in the Accounting World

Description

Depletion can be a common occurrence in today’s world where a rapid pace is the norm. Depletion is the using of a person’s self-monitoring resources that can erode one’s decision

Depletion can be a common occurrence in today’s world where a rapid pace is the norm. Depletion is the using of a person’s self-monitoring resources that can erode one’s decision making ability. Depletion affects people in their day-to-day personal and professional lives and can especially be problematic when it compromises career prospects. Professionals, such as doctors, lawyers, and accountants, all make important decisions daily and in pursuit of quality decision-making must exert self-control and avoid impulsive reactions to environmental events. Many studies have been conducted providing evidence of the harmful effects of cognitive depletion; an extensive literature focuses on the medical profession where poor decision-making has life-and-death consequences. This thesis reflects on the effect of depletion on accounting professionals. To that extent, behavioral experiments were conducted using student participants: students that will be future accountants. This study found that accounting students’ performance on a subsequent task was influenced if they had completed a difficult first task. Accountants, along with all professionals, need to be made aware of this circumstance to ensure that those who may be more susceptible to their resources being depleted can find ways to be aware of their self-control levels.

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Created

Date Created
  • 2019-05

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Modeling ADHD: impulsivity, hyperlocomotion, and sensitivity to nicotine in the SHR strain of rat

Description

ADHD is a childhood neurobehavioral disorder characterized by inordinate levels of hyperactivity, inattention and impulsivity. The inability to withhold a reinforced response, or response inhibition capacity (RIC), is one aspect

ADHD is a childhood neurobehavioral disorder characterized by inordinate levels of hyperactivity, inattention and impulsivity. The inability to withhold a reinforced response, or response inhibition capacity (RIC), is one aspect of impulsivity associated with ADHD. The first goal of this dissertation was to evaluate the fixed minimum interval (FMI) schedule as a method for assessing RIC. Chapter 2 showed that latencies were substantially more sensitive than FMI-derived estimates of RIC to the effects of pre-feeding and changes in rate and magnitude of reinforcement. Chapter 3 examined the ability of the FMI to discriminate between spontaneously hypertensive rats (SHR), an animal model of ADHD, and Wistar Kyoto (WKY) controls. Results from Chapter 3 showed that RIC was not substantially different between SHR and WKY rats. However, latencies were significantly shorter for SHRs than for WKYs suggesting incentive motivation differed between strains. The second goal of this dissertation was to examine the sensitivity of the SHR to nicotine. ADHD is a risk factor for tobacco dependence. The goal of Chapters 4 and 5 was to determine whether the SHR provided a model of ADHD-related tobacco sensitivity. Chapter 4 examined nicotine's locomotor and rewarding effects in adolescent SHRs using the conditioned place preference (CPP) procedure. SHRs developed CPP to the highest nicotine dose tested and were sensitive to nicotine's locomotor-enhancing properties. WKY controls did not develop CPP to any nicotine dose tested and were not sensitive to nicotine's locomotor properties. However, it is likely that nicotine effects were obscured by a pseudo-conditioning to saline in WKYs. Chapter 5 demonstrated that SHRs were more active than WKYs in the open-field but not in the Rotorat apparatus. Results also showed that SHRs and WKYs were both sensitive to nicotine's locomotor sensitizing effects. However, WKYs were more sensitive than SHRs to nicotine's locomotor suppressing effects. Collectively, results from Chapters 4 and 5 show that SHRs are sensitive to the rewarding and locomotor-enhancing properties of nicotine. However, more research is necessary to confirm that SHRs are a suitable model for studying ADHD-related tobacco use.

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Created

Date Created
  • 2015

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Impulsivity and the experience of childhood trauma on the effect of psychological maladjustment

Description

Research in the area of childhood trauma has shown a substantial amount of psychological maladjustment following the experience of traumatic events in childhood. Trauma survivors are at risk for developing

Research in the area of childhood trauma has shown a substantial amount of psychological maladjustment following the experience of traumatic events in childhood. Trauma survivors are at risk for developing a multitude of adverse psychological outcomes as well as unsafe behaviors following the event of trauma. One unifying theme within these psychological sequelae is the nature of impulsive behaviors. Delay-discounting refers to the subjective decrease in value of a reward when its presentation is delayed. Delay-discounting is often used as an index of impulsive behavior. This study poses two primary questions: 1) Can childhood trauma predict rates of delay-discounting? 2) Could delay-discounting predict psychological maladjustment for individuals who have experienced childhood trauma? This study will seek to answer these questions using an online version of the Kirby et al., 1999 hypothetical delay-discounting method, as well as the Barratt Impulsiveness Scale (BIS-11), to measure trait impulsivity. Measures of depression (BDI-II), life events (LEC), post-traumatic stress (PCL-C), and drug and alcohol abuse (DAST-20) will also be included. Participants included a sample of university students ages 18-52 (n=521, females = 386, males = 135) with a mean age of 25.19 years. Results indicated that childhood trauma was not a significant predictor of delay-discounting rate, nor was delay-discounting rate a significant predictor of psychological maladjustment. Limitations and future directions are discussed.

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Created

Date Created
  • 2012

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Effects of nicotine on response inhibition and fos activation in spontaneously hypertensive and wistar kyoto Rats

Description

Smoking remains the leading cause of preventable death in the United States, and early initiation is associated with greater difficulty quitting. Among adolescent smokers, those with attention-deficit hyperactivity disorder

Smoking remains the leading cause of preventable death in the United States, and early initiation is associated with greater difficulty quitting. Among adolescent smokers, those with attention-deficit hyperactivity disorder (ADHD), characterized by difficulties associated with impulsivity, hyperactivity, and inattention, smoke at nearly twice the rate of their peers. Although cigarette smoking is highly addictive, nicotine is a relatively weak primary reinforcer, spurring research on other potential targets that may maintain smoking, including the potential benefits of nicotine on attention, inhibition, and reinforcer efficacy. The present study employs the most prevalent rodent model of ADHD, the spontaneously hypertensive rat (SHR) and its control comparison Wistar Kyoto (WKY) to examine the effects of acute and chronic subcutaneous nicotine injections on performance in three operant response inhibition paradigms. Functional activation in select regions of the prefrontal cortex and striatum was also explored. Acute (0.1, 0.3, 0.6 mg/kg) and chronic (0.3 mg/kg) nicotine increased impulsive responding regardless of strain, dose, or operant schedule. Dose-dependent decreases in latency to initiate the task were also observed. SHR receiving daily nicotine injections showed less activation in the nucleus accumbens shell compared to saline controls. Despite close similarities, one of the three operant tasks did not detect response inhibition deficits in SHR relative to WKY. A closer examination of these tasks may highlight critical components involved in the amelioration of response inhibition deficits.

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Created

Date Created
  • 2014

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The Development of Impulsivity and Sensation Seeking: Sources of Between- and Within-Individual Differences Over Time and Across Sex

Description

Criminological theories have long incorporated personality traits as key explanatory factors and have generally relied on assumptions of trait stability. However, growing evidence from a variety of fields including criminology,

Criminological theories have long incorporated personality traits as key explanatory factors and have generally relied on assumptions of trait stability. However, growing evidence from a variety of fields including criminology, psychology, and neurobiology is demonstrating that personality traits are malleable over the life-course, and substantial individual variation exists in the developmental patterns of personality traits over time. This research is forcing criminologists to consider how and why “enduring” individual characteristics may change over the life course in ways that are meaningfully related to offending. Two traits that have been consistently linked to offending and conflated in key criminological theories (i.e. Gottfredson and Hirschi’s self-control theory), impulsivity and sensation seeking, have recently been shown to be independent personality traits with different normative maturational timetables and biological underpinnings. This dissertation extends this work by examining developmental patterns of impulsivity and sensation seeking and social sources of variation in these traits with the Family and Community Health Survey, a longitudinal data set that consists of approximately 900 African American youth and their families followed from late childhood to their late-twenties. Multiple longitudinal modeling methods are employed (hierarchical linear modeling and group-based trajectory modeling) to address this research agenda. Results from this dissertation lead to four broad conclusions. First, and in support of existing research, there is substantial variability in developmental trajectories of impulsivity and sensation seeking. Average developmental trajectories of these traits greatly mask the degree of individual variability in developmental patterns that exists. Second, social factors are significantly associated with levels of impulsivity and sensation seeking. Socio-environmental experiences characterized by hostility and unsupportiveness are generally associated with elevated levels of impulsivity and sensation seeking while socio-environmental experiences characterized by warmth and supportiveness are associated with lower levels of impulsivity and sensation seeking. Third, sex differences in developmental patterns of impulsivity are nonexistent while sex differences in developmental patterns of sensation seeking are significant. Finally, with few exceptions, predictors of trait levels operate in a general fashion such the same factors typically explain both male and female trait levels and produce similar effects on impulsivity and sensation seeking.

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Created

Date Created
  • 2019

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The Effect of Risk Aversion, Loss Aversion and Impulsivity on Delay Discounting

Description

Delay discounting is the decline in the present value of a reward with delay to its receipt. (Mazur,1987). The delay discounting task is used to measure delay discounting rate, which

Delay discounting is the decline in the present value of a reward with delay to its receipt. (Mazur,1987). The delay discounting task is used to measure delay discounting rate, which requires the participants to choose between two options: one involves immediate delivery of a reward, and other involves delivery after a delay, and the immediate rewards are adjusted in value until the subject feels there is no difference between the immediate and the delayed reward. Some previous studies (Robles and Vargas, 2007; 2008; Robles et al., 2009) found that the order of presentation of the immediate rewards (ascending or descending) significantly influenced the estimated delay discounting rate, which is known as the order effect. Uncertainty about the future and impulsivity could explain delay discounting behavior. The purpose of this study was to explore the order effect in delay discounting assessment. The current study found that the order effect in the delay discounting task can be explained by risk aversion, loss aversion and impulsivity. In the current study, the two kinds of fixed procedure (ascending and descending), and the titrating delay discounting task were used to estimate the degree of delay discounting. Also, two gambling tasks were applied to measure risk and loss aversion indices. The BIS-11 scale was used to assess the level of trait impulsivity. The results indicated that impulsivity biases individuals to choose the immediate small reward rather than the large delayed reward, resulting in lower area under the discounting curve (AUC) when estimated with the ascending-sequence delay discounting task. Also, impulsivity moderated the relationship between loss aversion and AUC estimated with the descending-sequence delay discounting task.

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Agent

Created

Date Created
  • 2018