<p>Four experiments were undertaken to identify properties of differential reinforcement relevant to response differentiation. Differential reinforcement was given for the length of "runs" of pigeons' key pecks, the length of a run being defined as the number of responses on a key preceding a spatially different terminal response.</p> <p>In Experiment I, a criterion run-length was assigned each subject and each subject was reinforced only following emission of a run-length which exceeded its criterion. Criterion run-lengths of 5, 10 and 20 responses were assigned to different groups. Mean run-lengths (N) were related to criteria (n) by a power function:N = 2.63 n^0.69. The fractional exponent of this function implies that the proportion of responses exceeding criterion was lower for higher criterion values. Because reinforced response values were confined to an extreme of the dis tribution, a lower proportion of reinforced response values indicated a greater difference between the distribution of values of the response emitted by a subject and the distribution of values reinforced. Since higher criterion values produced higher asymptotic mean run-lengths, the differential between emitted and reinforced run-lengths was also related to asymptotic run-length.</p> <p>A similar relationship between mean run-length and the proportion of responses exceeding a criterion was obtained in Experiments II and III. These experiments used a differential reinforcement paradigm in which thecriterion was continuously adjusted for each subject so that a constant proportion of its distribution of run-lengths exceeded its criterion. In Experiment II, the proportion of the distribution exceeding the criterion was set at 15%, 30% or 45%, for different groups. However, only a random half of the run-lengths exceeding the criterion for animals in the 30% group, and one-third of those for the 45% group were actually reinforced, so that the overall probability of reinforcement was constant at 0.15 for all groups. Increases in the mean length of runs were obtained for all groups, with the 15% group exhibiting a more rapid change and a higher asymptotic mean run-length than the 30% group, which in turn exceeded the 45% group.</p> <p>In Experiment III, pigeons were reinforced only for run-lengths in the most extreme 30% of their run-length distributions. One group received reinforcement for a random half of these run-lengths, while others received reinforcement for all of the run-lengths in this range. The relative extremeness of run-lengths selected for reinforcement was therefore constant (30%) 'vhile the overall probability of reinforcement was either 0.30 or 0.15. Increases in mean run-length were obtained, but no differences in the rate of change or asymptotic mean run-length were found between groups.</p> <p>The results of Experiments II and III suggest that the relative extremeness of run-lengths selected for reinforcement, that is the differential between emitted and reinforced run-lengths, determines the rate and extent of changes in values of a response. The relationship between the relative extremeness of reinforced response values and the rate and extent of changes in emitted response values was further</p> <p>demonstrated in Experiment IV. Reinforcement was provided for a fixed area of the distribution of run-lengths closest to a specified target value. For one group, the area of the distribution reinforced was 15%, while another group was reinforced for a random half of run-lengths in the closest 30% to the target. Reinforcement probability was thus held constant at 0.15. Mean run-lengths changed in the direction of the target at a rate dependent on the difference between the mean run-length and the target run-length. An asymptote was reached (rate of change = 0) when mean run-length approached the target value (differential = 0). The relationship between asymptotic mean run-length and target run-length was nearly linear for both 15% and 30% groups.</p> <p>The results of this series of experiments were discussed in terms of a hypotnetical differentiation process emphasizing the differential between the central tendencies of the distributions of emitted and reinforced response values, expressed in percentage units. When a differential exists, a change in the distribution of response values occurs in a direction which tends to reduce the differential, and at a rate proportional to the magnitude of the differential. When no differential exists, no change occurs. Since change in many dynamic response properties is resisted in a way which suggests an opponent process (e.g.iLaw of Least Effort), the asymptote reached after differential reinforcement represents an equilibrium between differential reinforcement and its opponent process. The increased effectiveness of differential reinforcement when relatively more extreme response values are reinforced would thus not only result in greater rates of change, but would also overcome the resistance of the opponent process to a greater extent,shifting the equilibrium point to a higher value.</p> / Doctor of Philosophy (PhD)

Traumatic brain injury (TBI) causes life-debilitating conditions. While patient survival after a TBI has improved, the outlook for quality of life after TBI currently remains poor. In order to address this problem, there is a significant unmet need for new therapeutic options to prevent progression of deficits associated with TBI. To this end, we investigated two strategies to combat the deleterious affect of TBI. First, we targeted cerebral acidosis associated with TBI by testing whether disruption of acid sensing ion channel 1a (ASIC1a) in CNS, or buffering acidosis with sodium bicarbonate, could prevent neurological deficits after TBI. We next tested whether treatment with the neovel class of aminopropyl carbozoles, known as the P7C3 series, could also prevent TBI-associated neurological decline. Using the mouse fluid percussion injury model of TBI, we observed post-injury acidosis in the cortex, consistent with what has been shown in humans following brain injury. Administering HCO3- after fluid percussion injury prevented acidosis and reduced neurodegeneration. Because acidosis activates acid sensing ion channels (ASICs), we also studied AIC1a-/- mice and found reduced neurodegeneration after injury. Both HCO3-3 administration and loss of ASIC1a reduced functional deficits caused by fluid percussion injury. These results suggest that fluid percussion injury induces cerebral acidosis, which activates ASIC channels in the brain and contributes to neurodegeneration. Blocking ASIC1aactivity may thus offer a new therapeutic strategy to attenuate the adverse consequences of TBI. We next applied the blast injury model of TBI to test whether the P7C3 class of neuroprotective aminopropyl carbazoles would be of therapeutic benefit. In addition to preventing neuronal cell death, P7C3 molecules also preserved axonal integrity before neuronal cell loss in this model. The mechanism of P7C3 neuroprotection may be linked to its ability to activate the enzyme, nicotinamide phosphoribosyltransferase, which catalyzed the rate limiting step of nicotinamide adenine dinucleotide salvage pathway. Administration of the lead compound in the series, P7C3-S243, 1 day after blast-mediated TBI blocked axonal degeneration and preserved normal synaptic activity. P7C3-S243 administration also reduced neuronal functional deficits, including impaired learning, memory, and motor coordination in mice. We additionally reported persistent neurologic deficits and acquisition of anxiety-like phenotype in untreated animals 8-months after blast-mediated TBI. Optimized variants of P7C3 thus offer hope for identifying neuroprotective agents for conditions involving axonal damage, neuronal cell death, or both. Together, the results of this body of work identify novel therapeutic interventions that may attenuate deficits associated with TBI, and thus improve the quality of life in people after TBI.

The focus of this study was to explore the impact of challenging behaviors on Applied Behaviors Analysis treatment in Autism Spectrum Disorder. The prevalence of ASD is on the rise, so it is important that we understand how patients are responding to treatment. In this study, we cluster patients (N=854) based on their eight observed challenging behaviors using k-means, a machine learning algorithm, and then perform a multiple linear regression analysis to find significant differences between average exemplars mastered. The goal of this study was to expand the research in the area of ABA treatment for ASD and to help provide more insight helpful for creating personalized therapeutic interventions with maximum efficacy, minimum time and minimum cost for individuals.

Adherence to traditional masculinity has been associated with negative physical and psychological health outcomes. Specifically, the standards of masculinity imposed on men have been associated with high levels of stress reactivity, interpersonal violence, and substance abuse. However, previous research has been limited to primarily Caucasian samples. In order to better understand masculinity and the stress associated with adherence to masculinity across ethnicity, we examined the validity of the Masculine Gender Role Stress scale in a diverse sample. We hypothesized that the MGRS in a diverse sample would function similarly to the MGRS in a primarily Caucasian sample in that it would be reliable and valid and that a five factor model of MGRS would be the best fit. Undergraduate students (N = 234) completed the MGRS scale and several questionnaires measuring masculinity, stress, anger and anxiety. A confirmatory factor analysis was conducted in order to assess the validity of the five-factor model of the MGRS scale in a diverse sample. Results confirmed that the MGRS is valid among a diverse sample, a diverse Caucasian excluded sample, and a Hispanic only sample. Additionally, the five factor model was the better fit for all samples evaluated.

Although the negative associations between marital conflict and children’s adjustment are well documented, less is known about how marital conflict styles (e.g., engagement, withdrawal, problem solving and compliance) are related to children’s developmental outcomes. The present study seeks to determine what types of parents’ conflict styles, during the child’s first year of life, are related to children’s behavioral outcomes in the first grade. Analyses examine the hypothesis that more conflictual conflict resolution styles of parents during a child’s infancy will predict poorer child outcomes over time. In addition, given the growing literature documenting the first year of life as a particularly sensitive period in children’s development, the proposed study will explore the effect of parents’ conflict resolution styles in the child’s first year of life on child outcomes at age six, controlling for concurrent levels of conflict. Lastly this study will explore the interaction of parents’ conflict resolution style in predicting children’s outcomes. Conflict resolution style and children outcomes were examined in a sample of 153 working-class, first-time parents and their children. Participants were recruited through prenatal classes at hospitals and birth clinics, as well as through Women, Infants, and Children (WIC) offices in Western Massachusetts.

The purpose of this study was to examine the genetic and environmental influences on lifetime quit attempt in three US adolescent and young adult twin samples (N total = 6,322). The study utilized a common-contingent-causal (CCC) model to estimate these factors for lifetime quit attempts, after accounting for the factors for lifetime cigarette use and cigarettes per day. The study also examined age and sex differences, as well as the degree of relationship between these smoking phenotypes. The results demonstrated significant genetic influences for lifetime quit attempts in adolescents and young adults. No sex differences were observed for the contributions of genetic and environmental factors for lifetime quit attempts. Furthermore, separate liabilities for lifetime quit attempts and lifetime cigarette use were found for most age groups. Study findings have important implications for promoting quit attempts in adolescents and young adults.

Although integrated primary care psychology services are becoming increasingly common, the literature lacks adequate research support for the longitudinal durability of treatment effects following the conclusion of brief primary care interventions. This study served as a follow-up program evaluation of psychological services for depression and anxiety provided at the Medical College of Virginia’s Ambulatory Care Center in Richmond, Virginia. Data were collected on 47 adult primary care patients who received treatment for depression and/or anxiety between six and 18 months prior to the follow-up telephone call. Data were collected on the trajectory of depression scores throughout and following treatment, treatment received by patients in the interim, and reasons provided by patients for discontinuing treatment. Analyses of these data indicated that primary care psychology services were effective in reducing patient anxiety and depression as measured by the GAD-7 and PHQ-9 respectively, even when controlling for additional treatment in the interim, and that patients as a group continued to improve over time following the conclusion of treatment. These preliminary results should be interpreted with caution, however, due to the study’s small sample size and lack of a control group. Study limitations, strengths, and future directions are addressed.

While caffeine withdrawal has been well-characterized, research on caffeine intake and factors associated with withdrawal has been limited. The present study examined prevalence rates of caffeine use and identified psychosocial factors associated with having caffeine withdrawal headaches (CWH). Participants were N = 1,989 college freshmen who participated in the 2011 Spit for Science project. Caffeine use was reported by 80% of the sample. Females were more likely than males to consume caffeine, and soda was the primary source of caffeine for both genders. As hypothesized, daily caffeine users were more likely to report CWH than non-daily users. When multivariable analyses examined other variables identified through univariable analyses, the most parsimonious model for distinguishing between those with and without CWH included the following set of predictor variables: daily caffeine use; female; non-white minority; peers with alcohol problems; greater neuroticism, and those reporting maternal depression or anxiety.

The purpose of this study was to describe the perceived barriers to obtaining psychiatric treatment at the Johnson City Community Health Center. The context of the study was a rural area in Eastern Tennessee. Five patients with confirmed DSM-IV mental health diagnoses were recruited during treatment and interviewed at the Johnson City Community Health Center after their scheduled appointments with a Mental Health Nurse Practitioner (MHNP). The semi-structured interview focused on perceived barriers to obtaining treatment, perceptions of treatment received, and perceived availability of treatment. From those interviews, two themes were identified and each of which had two sub-themes identified: Realities of Treatment with the sub-themes of Therapy-Related Realities and Logistics Realities, The Way It Is with the sub-themes of Take Care of It Myself and Don’t Want People to Know. The findings indicate that there is a duality of positive and negative aspects of treatment at Johnson City Community Health Center. Understanding the needs and perceptions of those with psychiatric diagnoses will assist all staff and mental health providers in developing programs that are better suited for those with psychiatric diagnoses receiving treatment from Johnson City Community Health Center.

This paper investigates what has caused a lack of Asian American leadership in the corporate space and how transformational leadership can be the solution for these people by using their culture to their advantage. This was accomplished through a comprehensive review of transformational leadership and the personality traits associated with it, as well as psychological research on Asian American issues in the workplace and the role of Asian American culture. Stereotyping and discrimination play a role in the workplace, but usually, what a person can do to combat these issues is not explicated. This thesis aims to fill in that missing information and gives evidence from research that shows that Asian people can take proactive measures against prejudice. They can try to reduce that stigma through a couple different techniques. Transformational leadership is the most effective form of leadership and the style that Asian people should use to become effective leaders. Luckily there are aspects of their culture that already helps them become competent leaders, so it is paramount for companies to nurture those positive qualities. By fixing these issues companies will promote the best personnel which will lead to higher productivity as transformational leaders increase output. Asian Americans will not feel like they are limited by their ethnicity. This will result in greater worker productivity and an actual diversity in the leaders of the company which will lead to higher revenue and a positive public image.