Browsing by Subject "Behavioral psychology"

In addition to the adverse effects of high blood pressure (HBP) on cardiovascular disease, HBP is also associated with increased risk of stroke, dementia, and neurocognitive dysfunction. Although aerobic exercise and dietary modifications have been shown to reduce blood pressure, no studies have examined the effects of a combined aerobic exercise and dietary intervention on neurocognition among individuals with HBP, a group at elevated risk for neurocognitive dysfunction. As part of a larger investigation, the ENCORE study, this study examined the effects of dietary modification alone and combined with aerobic exercise on neurocognitive function among individuals with HBP. One hundred twenty five individuals with high normal blood pressure were randomized to an aerobic exercise and dietary modification group (DASH + WM), dietary modification alone (DASH-A), or a usual care control group. Participants completed a battery of neurocognitive tests assessing executive function and vigilance at baseline and again following the four month intervention. Following the intervention, participants in the DASH + WM and DASH-A groups exhibited modest improvements in neurocognitive function relative to controls, and these changes appeared to be mediated by improved cardiovascular fitness and weight loss. A combined aerobic exercise and dietary intervention improves neurocognitive function among individuals with HBP.

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.

I present a framework that describes how perceived discrepancies from an ideal, or hoped-for, self influence how people view and behave with products associated with identity attainment (i.e., "symbolic props"). In the first half of this framework, I demonstrate that individuals who perceive that they are more discrepant from their aspired identity (i.e., more aspirationally discrepant individuals) view symbolic props as more "instrumental," or useful, in helping them achieve identity goals. I demonstrate that this effect is egocentric, mediated by motivation, and only occurs when the perceived rate of progress toward one's aspirational goals is high enough to merit engagement toward the goal. In the second half of the framework, I show that for more aspirationally discrepant individuals, the use of symbolic props may actually limit effort on goal-relevant tasks. These studies suggest an ironic effect whereby aspirational discrepancy may lead to acquisition of goal-relevant props to the detriment of performance-relevant effort.

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.

Among some researchers, there is an emerging conceptualization of chronic tic disorders (CTDs) as conditions that are partially rooted in avoidance of tic-related private experiences (i.e., painful or difficult thoughts and feelings) and internal sensations (i.e., premonitory urges to tic). The first specific aim of the present research was to investigate the possibility that experiential avoidance is related to tic severity and perceived quality of life in individuals with CTDs. The second aim was to determine whether the efficacy of Habit Reversal Training (HRT), the most prevalent and effective behavioral intervention for CTDs to date, might be enhanced by combining it with Acceptance and Commitment Therapy (ACT), an intervention that directly targets experiential avoidance. These aims were addressed by conducting two related studies. Study I, an online survey, included 239 adults (M = 37.6 years; SD = 13.8 years) who reported having been previously diagnosed with a CTD. Results showed that levels of premonitory urges, as well as both general and tic-specific experiential avoidance, were significantly positively related to tic severity. General and tic-specific experiential avoidance were also significantly negatively related to perceived quality of life. Psychometric analyses of two novel measures developed for Study I (i.e., the Yale Global Tic Severity Scale-Self-Report Version and the Acceptance and Action Questionnaire-Tic-Specific Version) demonstrated excellent internal consistency and convergent validity. Study II, a multi-site pilot investigation, involved 13 adolescents (M = 15.4 years; SD = 1.3 years) who were treated with either HRT alone or a novel HRT+ACT intervention. Results suggest that the HRT+ACT treatment is feasible, highly acceptable to both patients and parents, and as effective as HRT alone at reducing tic severity from pre-treatment through week 22 follow-up. Participants in both groups reported clinically significant post-treatment decreases in general and tic-specific experiential avoidance and improvements in overall functioning. Researchers concluded that experiential avoidance plays an important role in tic expression and overall functioning for individuals with CTDs. Results support additional development and testing of the promising HRT+ACT intervention, to evaluate its efficacy alone and in comparison to other relevant psychosocial and pharmacological interventions.

Recent studies have linked expressive suppression to impairments in interpersonal functioning, but the mechanism underlying this relationship has not been well articulated. One possibility is that the individual who engages in expressive suppression is impaired in perceiving the emotions of others, a critical ability in successful interpersonal functioning. In the current study, participants were presented with a series of photographs of facial expressions that were manipulated so that they appeared to "morph" from neutral into full emotion expressions. As they viewed these images, participants were instructed to identify the expression as quickly as possible, by selecting one of the six emotion labels (happiness, sadness, fear, anger, surprise, and disgust) on the screen. Prior to this task, participants were randomized to one of three groups: instructed to mimic the expressions on the screen, instructed to suppress all emotion expressions, or not given specific instructions on how to control expressions (the control group). The speed with which participants accurately identified emotional expressions (emotion sensitivity) was the primary variable of interest. Overall, participants in the suppression condition were found to be slower to accurately identify emotions, while no statistically-significant differences were found between the mimicry and no-instructions conditions. The decreased emotion sensitivity in the suppression group could not be accounted for by impulsive responding, decreased sensitivity at full expression, or perceived difficulty of task.

Altered dietary availability of the vital nutrient choline during early development leads to persistent changes in brain and behavior throughout adulthood. Prenatal choline supplementation during embryonic days (ED) 12-17 of the rodent gestation period enhances memory capacity and precision and hippocampal plasticity in adulthood, and protects against spatial learning and memory deficits shortly after excitotoxic seizures, whereas prenatal choline deficiency can compromise hippocampal memory and plasticity in adulthood. Recent evidence from our laboratory has determined that lifelong proliferation of newborn neurons in the adult hippocampus, a feature of adult hippocampal plasticity that has been implicated in some aspects of learning and memory, is modulated by early choline availability. Prenatal choline's effects on adult neurogenesis may be one mechanism for diet-induced cognitive changes throughout life and in response to injury, although little is known about the mechanisms underlying how prenatal choline alters adult neurogenesis or the neural mechanisms underlying prenatal choline supplementation's protection against cognitive deficits after seizures. To address these issues, the present set of experiments investigated how prenatal choline availability modulates specific properties of neurogenesis in the adult brain (in the intact brain and in response to injury), as well as hippocampal markers known to change in response to excitotoxin-induced seizures, and sought to relate changes in neurogenesis and in neuropathological markers following injury to changes in performance on spatial learning and memory tasks. Subjects in each experiment were adult offspring from rat dams that received either a control diet or diet supplemented with choline chloride or deficient of choline on ED 12-17. To measure neurogenesis, rats were given injections of the mitotic marker bromodeoxyurdine to label dividing cells in the hippocampus. Prenatal choline supplementation enhanced several properties of basal adult hippocampal neurogenesis (cell division and survival, neural stem/progenitor cell phenotype and proliferative capacity, trophic support), and this increase was associated with improvements in spatial working memory retention in a delayed-matching-to-place water maze task. In contrast, prenatal choline deficiency had little effect on basal adult hippocampal neurogenesis, and no effect on spatial memory performance. Prenatal choline supplementation also enhanced olfactory bulb neurogenesis without altering cell proliferation in the subventricular zone, while prenatal choline deficiency had no effect on either measure, showing for the first time that prenatal choline's effects on adult neurogenesis is similarly expressed in another distinct neurogenic region of the adult brain. Altered prenatal choline availability also modulated the hippocampal response to kainic acid-induced seizures where supplementation attenuated while deficiency had no effect on the injury-induced proliferative response of the dentate gyrus shortly after injury. Prenatal choline supplementation also attenuated other markers of hippocampal neuropathology shortly after seizures and promoted the long-term hippocampal recovery from seizures months after injury, including rescuing declines in adult hippocampal neurogenesis and in spatial memory performance in a standard water maze task. Taken together, these findings demonstrate a robust neuroprotective effect of prenatal choline supplementation that may be driven by enhanced adult hippocampal plasticity and trophic support prior to injury, and shed light on the mechanisms underlying how prenatal choline availability alters adult hippocampal neurogenesis, which may contribute to changes in memory capacity and precision both throughout life and following neural assault.

Opioid drug abuse represents a serious public health concern with few effective therapeutic strategies. A primary goal for researchers modeling substance abuse disorders has been the delineation of the biological and environmental factors that shape an individual’s susceptibility or resistance to the reinforcing properties of abused substances. Early-life environmental conditions are frequently implicated as critical mediators for later-life health outcomes, although the cellular and molecular mechanisms that underlie these effects have historically been challenging to identify. Previous work has shown that a neonatal handling procedure in rats (which promotes enriched maternal care) attenuates morphine conditioning, reduces morphine-induced glial activation in the nucleus accumbens (NAc), and increases microglial expression of the anti-inflammatory cytokine interleukin-10 (IL-10). The experiments described in this dissertation were thus designed to address if inflammatory signaling in the NAc may underlie the effects of early-life experience on later-life opioid drug-taking. The results demonstrate that neonatal handling attenuates intravenous self-administration of the opioid remifentanil in a drug concentration-dependent manner. Transcriptional profiling of the NAc reveals a suppression of pro-inflammatory cytokine and chemokine signaling molecules and an increase in anti-inflammatory IL-10 in handled rats following repeated exposure to remifentanil. To directly test the hypothesis that anti-inflammatory signaling can alter drug-taking behavior, bilateral intracranial injections of plasmid DNA encoding IL-10 (pDNA-IL-10) or control pDNA were delivered into the NAc of naïve rats. pDNA-IL-10 treatment reduces remifentanil self-administration in a drug concentration-dependent manner, similar to the previous observations in handled rats. Additional experiments confirmed that neither handling nor pDNA-IL-10 treatment alters operant responding for food or sucrose rewards. These results help define the conditions under which ventral striatal neuroimmune signaling may influence motivated behaviors for highly reinforcing opioid drugs.

Alcohol is a leading risk factor for injury. Road traffic injuries are a leading killer, but perceptions of drinking and drink driving in Tanzania are unclear. This research aims to define how perceptions of drinking influence risky driving behavior at Kilimanjaro Christian Medical Center in Moshi, Tanzania. This mixed methods study incorporated the Alcohol Adapted Perceived Discrimination-Devaluation scale (PDD) and the Alcohol Use Disorders Identification Test (AUDIT) among 96 injury patients regardless of their alcohol use prior to injury. Results were reported as medians and IQRs with Kurskal Wallis tests. Additionally, focus groups with injury patients, their families, and community members (n = 63) were conducted and analyzed in parallel using an inductive thematic content analysis approach. Of the 96 injury patients surveyed, 53 used alcohol and 17%(n=9) of those self-reported driving after ingesting 3 or more alcoholic drinks (SRDD). SRDD’s average AUDIT score (median=11) was significantly different from those who denied drink driving (median=6, p= 0.03). The PDD showed a high overall stigma, particularly discrimination, against those who use alcohol; but, the PDD was similar for drinkers and abstainers from alcohol (median=2.7 and 3.1, respectively). Thematic content analysis highlighted an ‘inability to change those that drink drive, ‘disapproving of drink driving’, and a ‘necessary police enforcement on drink driving.’ While stigma is present in Tanzania against those who use alcohol, it does not impact the choice to drink and drive, and was not stronger in drinkers or abstainers. Overall, there appears to be a community-wide disapproval of drinking and driving coupled with feeling unable to change this risky behavior.

AbstractBackground: Mental health significantly affects overall well-being, with childhood identified as a critical period for intervention. The family unit plays a pivotal role in shaping children's mental health, serving as both a source of support and, potentially, stress. In low and middle-income countries (LMICs) like Kenya, where access to mental health services is limited, the impact of family dynamics on children's mental health underscores the need for effective, culturally tailored interventions. The Tuko Pamoja program in Kenya offers a novel approach by integrating community-based prevention with targeted family counseling, addressing the gap in family-based mental health interventions within a community-embedded framework. Objective: This study aims to explore the factors influencing family participation in the Tuko Pamoja program, examining the experiences of families who engaged with the program and those who did not. It seeks to understand the interplay between the program's two components –group-based prevention (Tuko Pamoja Family Days) and individual family counseling (Tuko Pamoja Home) and participants' perceptions of their collective influence on family dynamics and mental health. Methods: Employing a qualitative research design, this study included in-depth interviews with 14 caregivers from families identified within the community with high levels of family distress. Thematic content analysis was conducted to identify themes related to participation decisions, program impact, and recommendations for improvement. Results: Findings reveal that non-attenders had positive perceptions of the program but were still unable to attend due to logistical barriers. Among attenders, effective recruitment strategies, clear communication, and logistical support facilitated participation in both tiers of the program. Attenders expressed that participation in TP Family Days played a crucial role in reducing stigma and encouraging participation in the more intensive TP Home counseling tier. Participants who engaged with both tiers reported significant improvements in family communication, parenting practices, and overall family dynamics, with both tiers reinforcing each other's content to enhance the overall impact. Conclusion: The Tuko Pamoja program demonstrates the potential to improve family dynamics and mental health awareness in LMIC settings by synergistically combining prevention and treatment tiers. Attenders felt that the program's prevention component played a crucial role in reducing stigma, improving family communication, and strengthening family relationships. This study contributes to the understanding of implementing family-based mental health interventions in LMICs, offering valuable insights into how integrated approaches can effectively address complex psychosocial needs within family systems. Addressing barriers to participation and enhancing program accessibility will be important for broadening the program's reach and efficacy. Keywords: Family-based interventions, Mental health, LMIC, Community-embedded model, Tuko Pamoja, Tuko Pamoja Home, Tuko Pamoja Family Days, Kenya, Qualitative research.

One of the most frequent things we do as consumers is make purchase. We pay for a coffee or for food, we pay for necessities around the house, we even pay for one another, buying drinks or dinner for a friend every now and then. In today’s marketplace, the decision of whether to purchase is also coupled with the decision of how to make a purchase. Consumers have so many different methods to pay for their transactions. Can the way a consumer chooses to pay change the likelihood that s/he make a purchase? And then post-purchase, can the payment method used to pay for a purchase influence how connected individuals feel to that product, brand, or organization? Given that we sometimes pay for others (and vice versa), can the way we pay influence our interpersonal relationships?

In what follows, I argue that the way individuals pay, and specifically the pain associated with making a payment, can have a pervasive effect on their decision to make a purchase and how they feel post-transaction. Across three essays, I focus on how the pain of paying can influence the likelihood to purchase an item from a consideration set (Essay 1) and subsequently, how the pain of paying can influence post-transaction connection to a product, organization, or even to other people (Essay 2 and 3). Across field, laboratory, online, and archival methods, I find robust evidence that increasing the pain of paying may initially deter individuals from choosing. However, post-transaction, increasing the pain of payment may have an upside: individuals feel closer and more committed to a product that they purchased, organization that they donated to, and feel greater connection and rapport to who they spent their money on. However, I also demonstrate the boundary conditions of these findings. When individuals are spending money on something that is undesirable, such as paying for a competitor, increasing the pain of payment decreases interpersonal connection and rapport.