Browsing by Subject "Behavioral sciences"

Background: Obesity is the number one health risk facing Americans. The obesity epidemic in America is attributed to physical inactivity, unhealthy food choices, and excessive food intake. Structured weight loss programs have been successful in initiating behavior change and weight loss; however, weight is almost always regained over time. The rate of weight gain is highest immediately after cessation of a structured weight loss program. Thus, effective interventions are needed that can successfully be used following a structured weight loss program to sustain weight loss and prevent weight relapse. Due to low cost, ubiquity, and ease of use, healthcare communicated through mobile technology, or "mHealth", may be able to serve as an effective medium to reach a large number of people to facilitate weight loss behaviors. Short message service (SMS), also known as text messaging, is easy to use, ubiquitous, affordable, and can target people directly where they are regardless of geographic location, socioeconomic status, or demographic factors. A review of the literature demonstrated limited information regarding message content, timing and frequency of message delivery and only 3 of 14 SMS-related interventions reviewed demonstrated a statistically significant effect on weight loss, diet or exercise. Additionally, information on how to integrate and leverage SMS as a health promotion tool for weight loss was also limited in the literature.

The Behavior Change Process model was used as a guide to understand how to develop an intervention to help people sustain recent weight loss. Furthermore, research suggests interventions that target and frame messages about how people reach goals in their life through either a prevention or promotion focus may be beneficial at motivating people to self-regulate and sustain recent behavioral changes. The goal of this study was to design an intervention that would help people stay in the continued response phase of the Behavior Change Process and help prevent weight relapse. Using the Behavior Change Process and regulatory focus theory, an intervention was developed that leveraged short message service (SMS) to deliver messages to people who have recently lost weight in attempt to help them sustain weight loss and prevent relapse.

Methods: First, a pilot study was conducted to inform the development of a SMS software application, the development of message content and the frequency and timing of message delivery. Second, an exploratory 3-arm mixed methods randomized controlled trial was conducted to test the feasibility, acceptability, perception of the usefulness, and efficacy of a weight loss sustaining mHealth SMS intervention among people with obesity. Participants (N=120) were randomized to a promotion message group, a prevention message group, or an attention-control general health message group. Participants completed baseline assessments, and reported their weight at 1 and 3 months post-baseline to assess efficacy of the intervention on sustaining weight loss. In addition, participants partook in a phone interview follow completion of the intervention to assess acceptability and usefulness.

Results: Participants found the message content and intervention acceptable and a majority perceived value in receiving messages via SMS that promote weight loss sustaining behaviors. Interview data implied that the intervention served as a reminder and daily cue to action. Participants were favorable towards receiving a daily reminder, which they noted helped them to stay focused, and in some cases to keep them motivated to continue losing weight. And a majority, 42 (91%) who participated in a telephone interview said that they preferred to get messages on their cell phone due to accessibility and convenience. A minimum of one message per day delivered at approximately 8:00 A.M. was deemed the optimal delivery time and frequency. This was particularly true for weight loss, which many participants reported as a daily struggle that begins every morning. With regards to sustaining weight loss, there was a statistical trend in sustained weight loss at months 1 and 3 in the promotion and prevention framed message groups compared to the control group in both the intent-to-treat and evaluable case analyses. Clinically, there was a significant decrease in mean weight of approximately 5 pounds at month 3 in the promotion and prevention groups compared to the control. Additionally, effect sizes indicated a large effect of the intervention on sustaining weight loss in the promotion and prevention groups relative to the control group.

Conclusion: Overall results showed that at the continued response phase of the behavioral change process, it was feasible to design an application to deliver promotion and prevention framed weight loss sustaining messages. In particular, prevention framed messages may have been more useful in helping participants sustain weight loss. Though there was less than 80% power to detect a statistically significant difference, the observed effect sizes in this study were significant and demonstrated a large effect of the promotion and prevention interventions on sustaining weight loss relative to control. Furthermore, there was a clinically significant increase in mean weight loss and in the number of people who sustained weight loss in the promotion and prevention intervention groups compared to control.

These findings may serve as a reference for future interventions designed to help people thwart relapse and transition from a state of sustaining recent weight loss behaviors to a state of maintenance. Technological tools such as this SMS intervention that are constructed and guided by evidence-based content and theoretical constructs show promise in helping people sustain healthy behaviors that can lead to improved health outcomes.

One of the outstanding goals of neuroscience is to understand how neural circuits are assembled to produce context appropriate behavior. In an ever changing environment, it is critical for animals to be able to flexibly respond to different stimuli to optimize their behavioral responses accordingly. Oviposition, or the process of choosing where to lay eggs, is an important behavior for egg-laying animals, yet the neural mechanisms of this behavior are still not completely understood. Here, we use the genetically tractable organism, Drosophila melanogaster, to investigate how the brain decides which substrates are best for egg deposition. We show that flies prefer to lay eggs away from UV light and that induction egg-laying correlates with increased movement away from UV. Both egg-laying and movement aversion of UV are mediated through R7 photoreceptors, but only movement aversion is mediated through Dm8 amacrine neurons. We then identify octopaminergic neurons as being potential modulators of egg-laying output. Collectively, this work reveals new insights into the neural mechanisms that govern Drosophila egg-laying behavior.

Financial decision-making in a complex and dynamic world poses many challenges including which information to use, how to filter out distractions, and how to arrive at a decision strategy that balances effort and accuracy in the face of imperfect information and cognitive constraints. Traditional financial education methods that provide more information to consider and thus require expending additional time and energy have had limited efficacy in improving long-term decision-making capacity. The research presented here takes a different approach by exploring the influence of context on the construction of value to elucidate mechanisms in consumer choice that underlie individual differences in decision-making. This approach uses computational modeling to identify the component parts of decision-making, eye tracking to measure attentional processes and information gathering strategies during choice, and functional neuroimaging (fMRI) to characterize how social networks modulate value representations in the brain. Characterizing the underpinnings of decision-making can help pinpoint which individual differences in the decision process lead to different choices. The research presented reveals that patience in intertemporal choice results from rapid, attribute-wise comparison of amounts with minimal attention paid to time information, whereas impatience results from slower integration of time and amount within options. Furthermore, measuring attention in purchasing behavior shows that budget size can influence the value of items through a comparison process with price. Finally, a public social context influences motivation for rewards for self but does not affect motivation to earn for charity. This mechanistic approach to understanding value construction and evidence accumulation in choice can help offer strategies grounded in human cognition for people to better adapt to their financial situation, hopefully increasing the likelihood of longer-term impact.

Humans are able to make adaptive decisions with the goal of obtaining a goal, earning a reward, or avoiding punishment. While much is known about the behavior and corresponding underlying neural mechanism relating to this aspect of decision-making, the field of cognitive neuroscience has focused almost exclusively on how these types of decisions are made in discrete choices where the set of possible actions is comparatively much smaller. We know much less about how human brains are able to make similar types of goal-directed decisions in continuous contexts which are more akin to the types of choices humans make in real-life. Further, how these processes are modified by the presence of other humans whose goals might influence one's own future behavior is currently unknown. Across three empirical studies, I address some of these gaps in the literature by studying human competitive decision-making in a dynamic, control paradigm in which humans interacted with both social and non-social opponents (Chapter 2 and Chapter 4). In Chapter 3, I show that brain regions heavily implicated in social cognition and value-based decision-making also play a role in tracking continuous decision metrics involved in monitoring instantaneous coupling between opponents, advantageous decision timing, and constructing social context. Collectively, the results in this dissertation demonstrate the utility in studying decision-making in less-constrained paradigms with the overall goal of gaining further understanding of how humans make complex, goal-directed decisions closer to real-world conditions.

Abstract

INTRODUCTION

Clergy are a dynamic group of the population: they point people to God, navigate social and spiritual waters, provide advice and guidance, and teach and visit parishioners. Research has shown that caregivers often neglect their health to tend to the health and well-being of others. Because of their unique role in society, the health and well-being of the clergy themselves is an important subject of research. While clergy health is a growing topic of interest in the Western world, very little is known. The few studies conducted on the health of clergy have found that in some areas, this group is less healthy than the general population due to their hectic schedules, lacking social support, and job-related stressors. With the exception of the United States, Canada, and Great Britain, almost nothing has been studied internationally regarding clergy health. In Africa, religion is known to play an important role in the daily life of its inhabitants; however, the overall well-being of clergy including mental, spiritual, and physical health remains under-studied. To date, nothing has been reported regarding the health of pastors in Kenya. This exploratory study sought to better understand how United Methodist Church (UMC) clergy in Western Kenya conceptualize health and how that relates to their health seeking behaviors.

METHODS

This study partnered with religion and public health researchers at Moi University in Eldoret, Kenya, and utilized qualitative methodology to gather information on the conceptualization of health among UMC clergy in Western Kenya. One hour in-depth oral interviews with seven clergy and two Associate District Superintendents and four focus group discussions were conducted with a total of 52 United Methodist Church clergy in Nyanza Province, Kenya in June and July 2012.

ANALYSIS

All transcripts were entered into QSR International's NVivo 10 qualitative data analysis software and coded. Two members of the research team coded an in-depth oral interview and focus group transcription to ensure replicability. A combination of Grounded Theory (GT) analysis and Interpretative Phenomenological Analysis (IPA) was used to interpret the data.

CONCLUSION

UMC clergy define health holistically as the complete well-being of a person in their mind, body, and spirit. Indigenous cultural traditions are still present within the UMC; pastors and parishioners will seek care from a magician rather than a medical doctor if they believe the disease stems from evil spirits. Religious beliefs relate to health seeking behavior in one of two ways: first, clergy believe God alone heals, and thereby view medical seeking behavior as unnecessary and second, clergy believe God alone heals, but view the doctor as a permitted conduit of healing. This knowledge learned from this exploratory study may help inform future interventions.

Children learn crucial skills like speech by imitating the behavior of skilled adults. Similarly, juvenile zebra finches learn to sing by learning to imitate adults. This song learning process enables laboratory study of juvenile imitative learning. But it also poses behavioral quantification challenges. Zebra finches produce hundreds of thousands of complex vocalizations during vocal development. These undergo learned changes with respect to acoustic features that are relevant to the animal but experimentally unknown \textit{a priori}. Recent developments in machine learning provide tools to reduce the dimensionality of complex behaviors, plausibly simplifying this inference challenge. These tools have not been validated on or applied to song learning problems.

Here, I validate the use of an autoencoder to extract copying-relevant features from zebra finch song. Then, I develop tools to quantify developmental song change with respect to extracted features. In particular, I generate forward models that quantify developmental changes in syllable acoustic distributions. I also develop a method to score syllable maturity on a rendition-by-rendition basis. Both these techniques reveal circadian behavioral patterns that differ between normally developing and untutored juveniles, suggesting that tutoring not only sets target song acoustics; it directly affects intrinsic features of practice behavior. Critically, these tools enable making concrete predictions from otherwise abstract song learning theories.

Disease risk in wild animal populations is driven by multiple factors, including host, parasite, and environmental traits, that facilitate the transmission of parasites and infection of hosts. Parasites inflict costs on their hosts that affect host fitness with downstream consequences on population structures and disease emergence patterns. Most disease risk-related studies are conducted in captive animals, while few have focused on free-ranging populations because of the logistical challenges associated with long-term monitoring of the hosts and sample collection. Hence, data regarding disease dynamics in natural populations are scarce, which limits our understanding of the ecological and evolutionary context of disease dynamics. In this thesis, we investigate the forces driving disease risk in wild primates and the possible consequences of infection on these hosts.

We used longitudinal and cross-sectional data sets from wild primate populations in Kenya, Eastern Africa, to examine the following aims: 1) the effect of host behavior on hormones associated with disease risk, 2) environmental and host factors that predispose individuals to helminth infections, and 3) the immune responses and fitness costs associated with helminth infections. First, we investigated how two maturational milestones in wild male baboons—natal dispersal and rank attainment—were associated with variation in fecal hormone metabolites (glucocorticoids and testosterone). These two hormones are generally considered to be immunosuppressive and are often associated with high parasite loads. Within this analysis, we also investigated whether changes in the frequencies of behaviors (mating and agonistic encounters) were associated with adult dominance rank attainment. Second, we investigated multiple sources of variance in helminth burdens in a well-studied population of wild female baboons, including factors that contribute to both exposure and susceptibility (group size, social status, rainfall, temperature, age, and reproductive status). Third, we investigated how hematological indices and body mass index were associated with helminth burden.

In the first study, our results revealed that rank attainment is associated with an increase in fecal glucocorticoids (fGC) levels but not fecal testosterone (fT) levels: males that have achieved an adult rank have higher fGC than males that have not yet attained an adult rank. We also found that males win more agonistic encounters and acquire more reproductive opportunities after they have attained adult rank than before they have done so. The second study revealed that female baboons in Amboseli were infected with diverse helminth taxa, including both directly transmitted and indirectly transmitted helminths. In general, high parasite risk was linked to large group sizes, low rainfall conditions, old age, and pregnancy, although these predictors varied somewhat across helminth species. Fecal GC levels were not associated with any measures of helminth burden. The third study found that helminth burdens were positively associated with circulating lymphocyte counts and negatively associated with neutrophil-lymphocyte ratios (NLR). We did not find any associations between helminth burdens and total WBC or eosinophil counts. Red blood cell indices were not predicted by our measures of helminth burden but instead varied with age class and sex. Helminth burdens were also negatively correlated with body mass index (BMI).

Overall, the findings of this thesis are consistent with the hypothesis that host and environmental traits are important predictors of disease risk and infection in wild primate populations. In addition, our results suggest that wild primates mount immune responses to helminth burden and that helminth infections may have detrimental consequences on host body condition. Our work enhances the limited data on sources of disease variation and associated costs in wild populations. It also emphasizes the continued need for disease surveillance and health monitoring in wild populations.

In chimpanzees, most females disperse from the community in which they were born to reproduce in a new community, thereby eliminating the risk of inbreeding with close kin. However, across sites, some females breed in their natal community, raising questions about the flexibility of dispersal, the costs and benefits of different strategies and the mitigation of costs associated with dispersal and integration. In this dissertation I address these questions by combining long-term behavioral data and recent field observations on maturing and young adult females in Gombe National Park with an experimental manipulation of relationship formation in captive apes in the Congo.

To assess the risk of inbreeding for females who do and do not disperse, 129 chimpanzees were genotyped and relatedness between each dyad was calculated. Natal females were more closely related to adult community males than were immigrant females. By examining the parentage of 58 surviving offspring, I found that natal females were not more related to the sires of their offspring than were immigrant females, despite three instances of close inbreeding. The sires of all offspring were less related to the mothers than non-sires regardless of the mother’s residence status. These results suggest that chimpanzees are capable of detecting relatedness and that, even when remaining natal, females can largely avoid, though not eliminate, inbreeding.

Next, I examined whether dispersal was associated with energetic, social, physiological and/or reproductive costs by comparing immigrant (n=10) and natal (n=9) females of similar age using 2358 hours of observational data. Natal and immigrant females did not differ in any energetic metric. Immigrant females received aggression from resident females more frequently than natal females. Immigrants spent less time in social grooming and more time self-grooming than natal females. Immigrant females primarily associated with resident males, had more social partners and lacked close social allies. There was no difference in levels of fecal glucocorticoid metabolites in immigrant and natal females. Immigrant females gave birth 2.5 years later than natal females, though the survival of their first offspring did not differ. These results indicate that immigrant females in Gombe National Park do not face energetic deficits upon transfer, but they do enter a hostile social environment and have a delayed first birth.

Next, I examined whether chimpanzees use condition- and phenotype-dependent cues in making dispersal decisions. I examined the effect of social and environmental conditions present at the time females of known age matured (n=25) on the females’ dispersal decisions. Females were more likely to disperse if they had more male maternal relatives and thus, a high risk of inbreeding. Females with a high ranking mother and multiple maternal female kin tended to disperse less frequently, suggesting that a strong female kin network provides benefits to the maturing daughter. Females were also somewhat less likely to disperse when fewer unrelated males were present in the group. Habitat quality and intrasexual competition did not affect dispersal decisions. Using a larger sample of 62 females observed as adults in Gombe, I also detected an effect of phenotypic differences in personality on the female’s dispersal decisions; extraverted, agreeable and open females were less likely to disperse.

Natural observations show that apes use grooming and play as social currency, but no experimental manipulations have been carried out to measure the effects of these behaviors on relationship formation, an essential component of integration. Thirty chimpanzees and 25 bonobos were given a choice between an unfamiliar human who had recently groomed or played with them over one who did not. Both species showed a preference for the human that had interacted with them, though the effect was driven by males. These results support the idea that grooming and play act as social currency in great apes that can rapidly shape social relationships between unfamiliar individuals. Further investigation is needed to elucidate the use of social currency in female apes.

I conclude that dispersal in female chimpanzees is flexible and the balance of costs and benefits varies for each individual. Females likely take into account social cues present at maturity and their own phenotype in choosing a settlement path and are especially sensitive to the presence of maternal male kin. The primary cost associated with philopatry is inbreeding risk and the primary cost associated with dispersal is delay in the age at first birth, presumably resulting from intense social competition. Finally, apes may strategically make use of affiliative behavior in pursuing particular relationships, something that should be useful in the integration process.

Sex differences in drug addiction are mediated in part by effects of the ovarian hormone estradiol (E2) within the ascending dopamine (DA) system from the midbrain to the striatum. Estradiol enhances the effects of psychostimulants, but the exact underlying mechanisms are unknown. Mice could serve as an ideal genetically-tractable model for mechanistic studies into sex and hormone effects within the DA system but have been under-utilized. This study sought to: 1) characterize psychostimulant-induced behavior in mice as an indirect but quantifiable measure of DA neurotransmission, and 2) elucidate the mechanism underlying E2's enhancement of psychostimulant effects in females using surgical, pharmacological, and genetic manipulations. The spontaneous behavior of mice during habituation to a novel environment and after the psychostimulants d-amphetamine (AMPH; 1, 2.5, and/or 5 mg/kg) and cocaine (COC; 5, 15, and/or 30 mg/kg) were assessed in open field chambers using both automated photobeam interruptions and behavioral observations. Behaviors were assessed in the following groups of mice: intact males and females; ovariectomized mice replaced with either E2 for 2 days or 30 minutes or with estrogen receptor-selective agonists; and female mice lacking either ERα (αERKO) or ERβ (βERKO) versus wildtype (WT) littermates. Brain psychostimulant concentrations and tissue content of DA and its metabolites were determined at the time of maximum behavioral stimulation. Psychostimulants induced behavioral activation in mice including both increased locomotion as detected with an automated system and a sequence of behaviors progressing from stereotyped sniffing at low doses to patterned locomotion and rearing at high doses. Intact female mice exhibited more patterned locomotion and a shift towards higher behavior scores after psychostimulants despite having lower AMPH and equivalent COC brain levels as males. Actively ovariectomized mice exhibited fewer ambulations and lower behavior scores during habituation and after psychostimulants than Sham females. Two days but not 30 minutes of E2 replacement restored COC-induced behavioral responses to Sham levels. ERα-selective PPT replacement in ovariectomized mice and genetic ablation of ERα in αERKO mice altered COC-stimulated behavior. Immunohistochemistry revealed that midbrain DA neurons in mice express ERβ but not ERα, and that non-DA cells in the midbrain and the striatum express ERα. These results indicate that E2 enhances COC-stimulated locomotion in mice through an indirect effect of ERα. ERα may alter behavior through presynaptic effects on DA neuron activity and/or through postsynaptic effects on transcription and signal transduction pathways within striatal neurons.

Physiological signals measured from the body, such as brain activity and motor behavior, can be used to infer different physiological states or processes in humans. Signal processing and machine learning often play a fundamental role in this assessment, providing unique approaches to analyzing and interpreting physiological data for a variety of applications, such as medical diagnosis and human-computer interaction. In this work, these approaches were utilized and adapted for two separate applications: brain-computer interfaces (BCIs) and the assessment of visual-motor skill in virtual reality (VR).

The goal of BCI technology is to allow people with severe motor impairments to control a device without the need for voluntary muscle control. Conventional BCIs operate by converting electrophysiological signals measured from the brain into meaningful control commands, eliminating the need for physical interaction with the system. However, despite encouraging improvements over the last decade, BCI use remains primarily in research laboratories. One of the biggest obstacles limiting their daily in-home use is the significant amount of time and expertise that is often required to set up the biosensors (electrodes) for recording brain activity. The most common modality for brain recording is electroencephalography (EEG), which typically employs gel-based “wet” electrodes for recording signals with high signal-to-noise ratios (SNRs). However, while wet electrodes record higher quality signals than dry electrodes, they often hinder frequent use because of the complex and time-consuming process of applying the electrodes to the scalp. Therefore, in this research, a signal processing solution was implemented to help mitigate noise in a dry electrode system to facilitate a more practical BCI device for everyday use in people with severe motor impairments. This solution utilized a Bayesian algorithm that automatically determined the amount of EEG data to collect online based on the quality of incoming data. The hypothesis for this research was that the algorithm would detect the need for additional data collection in low SNR scenarios, such as those in the dry electrode systems, and collect sufficient data to improve BCI performance. In addition to this solution, two anomaly detection techniques were implemented to characterize the differences between the wet and dry electrode recordings to determine if any additional types of signal processing would further improve BCI performance with dry electrodes. Taken as a whole, this research demonstrated the impact of noise in dry electrode recordings on BCI performance and showed the potential of a signal processing approach for noise mitigation. However, further signal processing efforts are likely necessary for full mitigation and adoption of dry electrodes for use in the home.

The second study presented in this work focused on signal processing and machine learning techniques for assessing visual-motor skill during a simulated marksmanship task in immersive VR. Immersive VR systems offer flexible control of an interactive environment, along with precise position and orientation tracking of realistic movements. These systems can also be used in conjunction with brain monitoring techniques, such as EEG, to record neural signals as individuals perform complex motor tasks. In this study, these elements were fused to investigate the psychophysiological mechanisms underlying visual-motor skill during a multi-day simulated marksmanship training regimen. On each of 3 days, twenty participants performed a task where they were instructed to shoot simulated clay pigeons that were launched from behind a trap house using a mock firearm controller. Through the practice of this protocol, participants significantly improved their shot accuracy and precision. Furthermore, systematic changes in the variables extracted from the EEG and kinematic signals were observed that accompanied these improvements in performance. Using a machine learning approach, two predictive classification models were developed to automatically determine the combinations of EEG and kinematic variables that best differentiated successful (target hit) from unsuccessful (target miss) trials and high-performing participants (top fourth) from low-performing participants (bottom fourth). Finally, in order to capture the more complex patterns of human motion in the spatiotemporal domain, time series methods for motion trajectory prediction were developed that utilized the raw tracking data to estimate the future motion of the firearm controller. The objective of this approach was to predict whether the controller’s virtually projected ray would intersect with the target before the trigger was pulled to shoot, with the eventual goal of alerting participants in real-time when shooting may be suboptimal.

Overall, the findings from this research project point towards a comprehensive psychophysiological signal processing approach that can be used to characterize and predict human performance in VR, which has the potential to revolutionize the design of current simulation-based training programs for realistic visual-motor tasks.

Attentional processes are critical aspects of the neural, cognitive, and computational mechanisms of decision-making. However, the role of such processes is often not given much focus in decision-making research, especially for studies involving economic decision-making. Here, I present three studies that evaluated the role of attention during decision making. Study 1 evaluated the role of attentional control, such as top-down and bottom-up control, in mediating conflict between internal and external demands on attention to promote optimal task performance in a discrimination decision task. Results from Study 1 provided novel neural insights into the role of attentional control in processing and resolving conflict between internal representations and external stimuli during everyday decision-making. Studies 2 and 3 evaluated the role of selective attention, namely online feature-based selective attention, underlying mechanisms of delay and effort discounting in economic decision-making. Results from these two studies demonstrated the importance of measuring (online and parametrically) and utilizing feature-based selective attention during comparative decision-making tasks to better quantify the cognitive and computational mechanisms underlying behavior and preferences. Taken together, results from all three studies provide important quantitative and qualitative implications for understanding mechanisms of decision-making through the lens of attention.

AbstractBackground: In 2020, Tanzania struggled with significant HIV-related challenges, including 1.4 million people living with HIV (PLWH), 33,000 new infections, and 22,000 AIDS-related deaths. Suicide emerged as a main cause of mortality among PLWH, accounting for over a quarter of all suicides. Despite these alarming statistics, mental health resources remained scarce, with only 55 psychologists and psychiatrists in the country. Clinic staff in HIV care were tasked with providing counseling despite limited mental health training, primarily focusing on HIV education. This study aimed to delve into the lived experiences of PLWH with recent suicidal ideation to inform tailored mental health interventions. Methods: Participants were screened for suicidal ideation during routine HIV clinic visits, with qualitative interviews conducted thereafter. Data was analyzed using thematic analysis facilitated by NVivo 12 software. Results: PLWH experiencing suicidal ideation encounter significant mental health challenges originating from factors such as their HIV diagnosis, societal stigma, financial stress, and broader social determinants. Death is sometimes perceived as an escape from the challenges associated with HIV. Coping mechanisms include seeking assistance from religious leaders. While participants expressed openness to counseling, limited treatment options hinder access. Conclusion: Suicide is an urgent public health challenge among PLWH in Tanzania, exacerbated by unique stressors like socioeconomic challenges, stigma, discrimination, and psychological distress. Despite the seriousness of these challenges, options for mental health treatment are scarce and not tailored to the needs of PLWH. Our findings can inform the improvement of mental health care for PLWH in Tanzania and other low-resource settings.

Key Words: Tanzania, HIV, Suicide, Suicidal ideation, Mental health, lived experience, Qualitative research, Stigma, Coping mechanisms, Counseling intervention, Socioeconomic challenges, Discrimination, Psychological distress, Treatment options and Low-resource settings.

Background: Prior studies have produced conflicting results regarding the associations between partner-level characteristics and antiretroviral treatment (ART) adherence, with some findings suggesting that romantic or sexual partners negatively impact ART adherence in women. This study aimed to examine ART adherence in association with individual- and partner-level factors among South African women with sexual trauma histories, a particularly vulnerable group with low levels of ART adherence. Methods: Data were collected as part of a larger trial of HIV-infected women with trauma histories in Cape Town. A structured survey assessed partner characteristics, including the frequency of partner drinking and serostatus-disclosure, as well as individual-level factors. The level of ART nonadherence was measured in the parent trial through medical record abstraction. Univariate and multivariate linear regression analyses were used to explore possible individual- and partner-level predictors of ART nonadherence. Log likelihood ratio tests were used to examine the possible moderation of disclosure on the association between hazardous drinking and ART nonadherence. Results: The combination of hazardous drinking and partner drinking accounted for a significant percentage of the variance in ART nonadherence (F(2, 41) = 3.632, p < .05). HIV-serostatus disclosure was found to significantly modify the relationship between hazardous drinking and nonadherence (LR chi2(1) = 5.67, p < .05). Conclusions: This study found that the frequency of partner drinking and hazardous drinking were significantly associated with ART nonadherence in HIV-seropositive South African women. These analyses additionally found that HIV-serostatus disclosure to a partner exacerbated the effects of hazardous drinking on nonadherence. These findings point to the importance of addressing problem drinking in women and men, and of considering the impact of partners on ART adherence.

Background: Hypertension is a primary risk factor for cardiovascular disease. Studies have shown that hypertension may have a more severe effect on cardiovascular disease outcomes among women. To mitigate this risk of hypertension in women, evidence supports that the DASH (Dietary Approaches to Stop Hypertension) diet as an effective treatment. Despite decades of evidence supporting the efficacy of the DASH diet to treat hypertension, compliance to DASH remains consistently low across all populations. However, given the importance of self-monitoring for producing behavior change, innovative efforts that utilize this strategy are needed to improve adoption of DASH on a population level. Methods: This thesis is a secondary analysis of 3-month digital health intervention (DASH Cloud) to improve adoption of DASH among high risk women conducted in Durham, NC at Duke University. Participants (N= 59) were allocated into the DASH Cloud arm (N= 30), or the attention control arm (N = 29). Both groups received publicly available booklets about the DASH diet and were asked to self-monitor their diet using a commercially available diet tracking app. Only the intervention arm received personalized feedback about their compliance to the DASH diet and skills training videos via text message. The goal of this study was to understand patterns and predictors of self-monitoring via the diet tracking app. Results: Overall, the median proportion of self-monitoring engagement was 76%. By treatment arm, the median proportion of engagement in the DASH Cloud arm and attention control arm was 68% and 85%, respectively. Significant predictors of self-monitoring include those who had 100% engagement during the first two weeks and first month of the study, had marital support, lower BMI, at least a college degree, insurance, a negative perception of their food environment, were somewhat comfortable with using apps and less likely to use an app to track medication adherence. Conclusion: This study provided evidence that self-monitoring of diet is high within the context of an intervention aimed at using digital health to promote compliance to the DASH diet among high risk women. The strongest predictor of self-monitoring engagement was early engagement. This suggests that interventions aiming to improve rates of self-monitoring an improve uptake of DASH using diet tracking apps should aim to improve early engagement to achieve success overall. However, given the small sample size of the study, future studies should include a larger population to describe patterns of self-monitoring and ascertain other predictors of engagement.

Background: The global rise in early-onset type 2 diabetes (T2D) is impacting the lives of millions of young individuals around the world. To address the knowledge gap and emotional burden in young adults with T2D, the research team designed a four-week education and goal-based peer support intervention, Kanasina Gulabi (Kannada: My Dream Rose), implemented in Mysore, India between June and July 2023. Methods: The Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) framework was used to assess feasibility. Peer navigators (n=3, mean age: 33 years) were recruited from the community and trained to deliver the intervention. Twenty-eight adults ≤ 40 years of age with T2D were recruited and quasi-randomly allocated to the intervention group (n=14, mean age: 33 years) or the control group (n=14, mean age: 33 years). Hemoglobin A1c, T2D knowledge, diabetes distress, diabetes-related stigma, depression severity, and optimism were assessed at baseline, immediately after the intervention, and at the 2-month follow-up. Attendance, fidelity, and acceptability were also assessed. Results: Intervention participants expressed high satisfaction with Kanasina Gulabi and gratitude for the guided knowledge and mentorship from their peer navigators. Participants displayed excellent attendance and adherence, with an average of 5 hours of Kanasina Gulabi exposure over 4 weeks. Peer navigators delivered the intervention with 100% fidelity. Results immediately following the intervention showed reductions in diabetes distress (Intervention: 30.9%, Control: 6.5%), diabetes-related stigma (Intervention: 25.3%, Control: 14.5%), and depression severity (Intervention: 58.3%, Control: 38.5%). Both groups presented an increase in T2D knowledge (Intervention: 19.7%, Control: 25.2%). Conclusion: Implementing Kanasina Gulabi in Mysore is feasible and acceptable, with intervention participants showing more positive changes on multiple psychosocial outcomes compared to the control group. Results support a full trial to evaluate its effectiveness and sustainability in young adults with T2D.

People expend a great deal of time and energy telling each other stories of events that are known to be invented. These fictional narratives—emerging from novels, films, television shows, radio dramas, and other media—can nevertheless leave an impact once a book’s cover is closed or the theater lights toggle on. This dissertation characterizes memories of fiction, a phenomenon both commonplace and understudied within empirical psychology. Not only is characterizing this behavior valuable in its own right, understanding how people remember and recruit memories of fiction also holds theoretical implications: any theory of memory which does not allow or account for how and why people recollect and use memories of events they know to be fiction is incomplete.

In Chapter 1, I knit together the theoretical precedent from prior work in autobiographical memory, mental models, and more, for considering memories of fiction as part of the “autobiographical record.” In subsequent chapters and across six studies, I examine the assumptions of this claim empirically. In Chapters 2 through 4, I characterize the subjective experience and function of memories of fiction by adapting established measures of autobiographical remembering across four studies, such as the Autobiographical Memory Questionnaire (AMQ), Centrality of Event (CES) scale, and Talking About Life Experiences (TALE) questionnaire (Berntsen & Rubin, 2006; Bluck et al., 2005; Rubin et al., 2003). I find that people readily ascribe phenomenological vivacity and functional significance to memories of fiction, and that these reports follow the same patterns as reports of memories of lived experience. On average, memories of fiction are less vivid and significant than personal memories, but not as a hard-and-fast-rule. Thus, these first four chapters provide evidence for claiming that the differences between memories of fiction and memories of lived experience are of degree, rather than kind. Chapter 5 (Studies 5 and 6) explore the extent to which memories from works of fiction are recruited to fulfill similar directive functions as autobiographical memories, especially in the absence of lived experience. Chapter 6 concludes by summarizing this body of work and a discussion of notable differences between memories of fiction and lived experience.

Background: Cancer stigma presents a critical barrier to care seeking, contributing to delayed presentation and poor cancer outcomes worldwide. The burden of cancer in Tanzania is on the rise, with cancer being the third-leading cause of death in the country. Despite rising incidence and poor outcomes of cancer, cancer-related stigma interventions have received low prioritization. There is a need for sound research that focuses on understanding attitudes driving stigma, its impact on care seeking and treatment adherence, and intervention models to reduce stigma. Methods: We administered three open-ended qualitative questions to 140 adults newly diagnosed with cancer in Moshi, Tanzania. The questions explored, (1) common attitudes toward people with cancer, (2) the perceived impact of cancer-related stigma, and (3) ideas for reducing stigma experienced by people with cancer. Patients were recruited during routine appointments at the Cancer Center at Kilimanjaro Christian Medical Center. Data were analyzed using a team-based, applied thematic approach and NVivo 12 software. Twenty percent of the responses were double coded to assess inter-coder agreement and exceeded a pre-established threshold of 80% agreement (84.9%). Results: Participants described stigma as a major challenge for treatment and for receiving support from their social networks. Perceptions of financial stress, misconceptions about cancer such as the belief that it is contagious, and fear of death were common attitudes driving cancer stigma. Participants feared that symptoms would prevent them from working and that the cost of cancer care would drive away loved ones. Stigma was not a ubiquitous response, as some participants reported increased care and social support from family members after a cancer diagnosis. Experiences of stigma contributed to feelings of shame, fear of burdening the family, reduced resources to access treatment, and disengagement from care. Common substitutes to medical therapies included religious interventions and traditional medicine, which were perceived as less expensive and less stigmatizing. Participants felt they would benefit from improved financial support and professional counseling, as well as education for families and communities to reduce stigmatizing attitudes and enhance social support. Conclusions: There is need for intervention studies focused on improving cancer literacy, community advocacy to reduce cancer stigma, and increasing support for people with cancer and their families. There is also a clear need for policy efforts to make cancer care more affordable and accessible to reduce the financial burden on patients and families.

Activation of monoaminergic receptors is essential to the mechanism by which psychostimulants and antidepressants induce changes in behavior. Although these drugs rapidly increase monoaminergic transmission, they need to be administered for several weeks or months in order to produce long-lasting alterations in behavior. This observation suggests that it is likely that molecular mechanisms downstream of receptor activation contribute to the effects of psychostimulants and antidepressants on behavior.

Recently, we and others have demonstrated that the methyl-CpG-binding protein 2 (MeCP2) contributes to both neural and behavioral adaptations induced by repeated psychostimulant exposure (Deng et al, 2010, Im et al, 2010). Psychostimulants induce rapid and robust phosphorylation of MeCP2 at Ser421 (pMeCP2), a site that is thought to modulate MeCP2-dependent chromatin regulation (Cohen et al, 2011), and this phosphorylation event is selectively induced in the GABAergic interneurons of the nucleus accumbens (NAc). In order to understand the signaling pathways that contribute to the pattern of pMeCP2 we observe, I characterized the monoaminergic signaling pathways that regulate pMeCP2. I found that activation of dopamine (DA) and serotonin (5-HT) transmission is sufficient to induce pMeCP2. The novel finding that drugs that activate serotonergic signaling induce pMeCP2 suggests that pMeCP2 may be involved in serotonergic mediated behaviors.

To determine the requirement of pMeCP2 in serotonergic mediated behaviors, I utilized mice that bear a knockin (KI) mutation that converts serine to alanine at 421 (S421A) (Cohen et al, 2011). After characterizing the behavioral phenotype of these mice, I conducted tests to assess anxiety- and depression-like behavior. I found that the KI mice do not display heightened anxiety in several assays. However, the KI mice exhibit depression-like behavior in the forced swim and tail suspension but show no differences compared to wild-type (WT) littermates in the sucrose preference test, suggesting that pMeCP2 may be implicated in the behavioral response to stressful stimuli.

Because we are interested in examining the role of pMeCP2 in the behavioral adaptations to chronic monoaminergic signaling, I then put the KI mice and their WT littermates through chronic social defeat stress, a behavioral paradigm in which repeated exposure to aggressive mice causes social avoidance that is reversed by chronic but not acute antidepressant treatment. Although the WT mice show an increase in social interaction following chronic imipramine treatment, the KI mice fail to show a behavioral response to chronic treatment. These data suggest that pMeCP2 may be implicated in the antidepressant action of chronic imipramine. Finally, investigation of the brain regions in which pMeCP2 may be contributing to the behavioral response to chronic imipramine treatment revealed that chronic but not acute imipramine treatment induces pMeCP2 in the lateral habenula (LHb), a brain region involved in the behavioral response to stress and reward. Together, these data implicate a novel role for pMeCP2 in depression-like behavior and the behavioral response to chronic antidepressant treatment.

An inescapable component to survival in a dynamic environment is detecting and reacting to signals of danger. One of the most elegant processes animals possess to handle this complex task is classical conditioning, wherein stimuli associated with an aversive event acquire the capacity to elicit defensive behaviors. This process helps ensure quick reactions prior to the occurrence of an imminent threat. A problem of living in a dynamic environment, however, is that reliable signals of danger are rarely re-encountered in the exact same form from one situation to the next. Thus, to be truly adaptive it is imperative for defensive responses to extend beyond a specific instance towards other exemplars that might portend the same negative outcome. While the phenomenon of stimulus generalization was recognized in the earliest studies of conditioning from Pavlov's laboratory, a century of conditioning research has not resolved how humans and other animals actually meet this challenge. The research presented herein employs a combination of psychophysiological and functional imaging methods to examine how humans recruit neurocognitive systems to determine what stimuli do (and do not) pose a threat. Results show that human fear generalization is a complex phenomenon affected by the perceptual and conceptual nature of the stimulus. Brain regions and functional networks involved in fear generalization comprise cortical areas involved in coding the representation of conditioned stimuli and subcortical regions involved conditioned learning and the production of behavioral responses, most notably the amygdala. These results reveal the importance of stimulus-specific factors in fear learning and generalization, provide support for anatomically constrained models of fear generalization, and contribute to the development of model systems of fear generalization processes in human anxiety disorders.

Just as biological life becomes more interesting and diverse when the edges of ecosystems meet, intellectual life crackles with energy and possibility when leaders from different disciplines collaborate. The recent emergence of behavioral economics, a fusion of economic theory with psychological cognitive theory, represents the best of what can happen when different fields collide. Behavioral economists combine the sophisticated and nuanced anthropology articulated by cognitive theorists such as Nobel laureate Daniel Kahneman with classical economic theory to offer more realistic models and

expanded explanatory power, giving particular insight into why humans do not always behave in ways that are purely rational and self interested. I show that theological reflection and pastoral leadership, specifically, have much to gain by undertaking a similar `behavioral turn' and exploring the insights cognitive theory offers. By exploring the nature and history of the behavioral turn in economics and then showing the relevance to Christology and theological anthropology, I lay the groundwork for a `behavioral theology'. Behavioral theology sheds light on the Chalcedonian full divinity and humanity of Christ and underscores the view of sin as hubris. Behavioral theology also encourages pastors to see themselves as choice architects responsible for making decisions that help busy and tired congregants be the people they desire to be. Finally, I will demonstrate the experimental spirit of behavioral theology in a study of one facet of ecclesial life: church numerical growth and decline, using an approach inspired by behavioral game theory. With the permission of Duke's Independent Review Board I observed sessions, local church governing bodies in the Presbyterian Church (U.S.A.), play two versions of a public goods game to determine

whether the willingness and ability of leaders to cooperate, defect, reward, and punish one another correlates to a congregation's ability to sustain membership.