Thesis (Ph.D.)--Boston University / Research in rodents and computational modeling work suggest a critical role for the hippocampus in representing overlapping memories. This thesis tested predictions that the hippocampus is important in humans for remembering overlapping spatial events, and that flexible navigation of spatial routes is supported by key prefrontal and striatal structures operating in conjunction with the hippocampus. The three experiments described in this dissertation used functional magnetic resonance imaging (fMRI) in healthy young people to examine brain activity during context-dependent navigation of virtual maze environments. Experiment 1 tested whether humans recruit the hippocampus and orbitofrontal cortex to successfully retrieve well-learned overlapping spatial routes. Participants navigated familiar virtual maze environments during fMRI scanning. Brain activity for flexible retrieval of overlapping spatial memories was contrasted with activity for retrieval of distinct non-overlapping memories. Results demonstrate the hippocampus is more strongly recruited for planning and retrieval of overlapping routes than non-overlapping routes, and the orbitofrontal cortex is recruited specifically for context-dependent navigational decisions. Experiment 2 examined whether the hippocampus, orbitofrontal cortex, and striatum interact cooperatively to support flexible navigation of overlapping routes. Using a functional connectivity analysis of fMRI data, we compared interactions between these structures during virtual navigation of overlapping and non-overlapping mazes. Results demonstrate the hippocampus interacts with the caudate more strongly for navigating overlapping than non-overlapping routes. Both structures cooperate with the orbitofrontal cortex specifically during context-dependent decision points, suggesting the orbitofrontal cortex mediates translation of contextual information into the flexible selection of behavior. Experiment 3 examined whether the hippocampus and caudate contribute to forming context-dependent memories. fMRI activity for learning new virtual mazes which overlap with familiar routes was compared with activity for learning completely distinct routes. Results demonstrate both the hippocampus and caudate are preferentially recruited for learning mazes which overlap with existing route memories. Furthermore, both areas update their responses to familiar route memories which become context-dependent, suggesting complementary roles in both learning and updating overlapping representations. Together, these studies demonstrate that navigational decisions based on overlapping representations rely on a network incorporating hippocampal function with the evaluation and selection of behavior in the prefrontal cortex and striatum.

abstract: Social scientists from many disciplines have examined trust, including trust between those with different religious affiliations, emotional antecedents of trust, and physiological correlates of trust. However, little is known about how all of these factors intersect to shape trust behaviors. The current study aimed to examine physiological responses while individuals engaged in a trust game with a religious in-group or out-group member. Participants were randomly assigned to one of four conditions in which they were presented with the target’s profile before playing the game. In each of the conditions the target was described as either Catholic or Muslim and as someone who engaged in either costly signaling or anti-costly signaling behavior. In addition to assessing the amount of money invested as a behavioral measure of trust, physiological responses, specifically cardiac interbeat interval (IBI) and respiratory sinus arrhythmia (RSA), were measured. I hypothesized that when playing the trust game with a Catholic target as opposed to a Muslim target, Christian participants would (1) report being more similar to the target, (2) trust the target more, (3) invest more money in the target, (4) have a more positive outlook on the amount invested, and (5) show greater cardiorespiratory down-regulation, reflected by increases in IBI and RSA. Findings revealed that Christian participants reported greater similarity and showed a non-significant trend toward reporting a more positive outlook on (greater confidence in/satisfaction with) their investment decision when playing a Catholic versus Muslim target. Additionally, Christian participants who played an anti-costly signaling Catholic target showed greater cardiorespiratory down-regulation (increases from baseline for IBI, reflecting slower heart rate, and increases in RSA) than Christian participants who played an anti-costly signaling Muslim target. Results from this study echo previous findings suggesting that perceived similarity may facilitate trust. Findings also are consistent with previous research suggesting that religious ingroup or outgroup membership may not be as influential in shaping trust decisions if the trustee is costly signaling; for anti-signaling, however, cardiorespiratory down-regulation to a religious ingroup member may be apparent. These physiological signals may provide interoceptive information about a peer’s trustworthiness. / Dissertation/Thesis / Masters Thesis Psychology 2019

<p> The purpose of this study was to examine potential effects of head-injury on individuals&rsquo; performance on the Picture Memory Interference Test (PMIT). This study examined differences in the performance of college-aged students with and without a history of head-injury on the PMIT. Data was drawn from an archival dataset of PMIT completions held at UCLA and analyzed with permission. From the total dataset of 12,227 completions, experimental groups were derived and separated based upon assumed severity of head-injury, based upon self-report data. Following exclusions, the final data sub-set for analysis consisted of 6,897 unique completions of the PMIT. Of these, 412 were assigned to the Mild head-injury group; 61 individuals were assigned to the Moderate-Severe head-injury group. Multiple one-way ANCOVA were conducted to identify difference between group performances. The results of the current study are unclear as to whether or not the PMIT may effectively detect and discriminate college student participants with a history of head-injury from those without, although significant findings were obtained which demonstrated those with a history of mild head-injury obtained higher scores on particular trials of the PMIT. </p>

Thesis (Ph.D.)--Pacific Graduate School of Psychology, 1994. / Source: Dissertation Abstracts International, Volume: 56-04, Section: B, page: 2321. Chair: Anita Greene.

Thesis (Ph.D.)--Pacific Graduate School of Psychology, 1997. / Source: Dissertation Abstracts International, Volume: 57-04, Section: B, page: 2931. Adviser: Mary R. Crittenden.

Thesis (Ph.D.)--Pacific Graduate School of Psychology, 1996. / Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4768.

abstract: Spirituality has been studied in relation to psychological factors in health for the past decade and has been found to promote positive affect while possibly benefiting health. However, multiple dimensions of spirituality need to be examined systematically before much can be concluded regarding the influence of spirituality on health. One purpose of this study was to test the validity of the four factors of the Psychomatrix Spirituality Inventory (PSI) developed by Wolman using confirmatory factor analysis (CFA): divinity, mindfulness, extrasensory perception, and intellectuality. In addition, the moderation effects of these factors on stress, assessed by cortisol levels, and on perceived cold symptoms induced by a bogus cold viral challenge were investigated among 100 participants as part of a larger study conducted by Nemeroff to identify psychological factors related to perceived cold susceptibility under a bogus viral challenge paradigm. The analysis of CFA among 265 participants indicated that the four-factor Pyscholmatrix Spirituality model did not provide a good fit to the data collected by Nemeroff. The shared variances among factors could be the explanation for failure to confirm these four factors. Women developed more cold symptoms than did men post bogus exposure. Mindfulness and extrasensory perception factors buffered the adverse effects of stress on cold symptoms. A three-way-interaction among gender, stress, and mindfulness indicated that the buffering effects of mindfulness on stress and cold symptoms were stronger for women than for men, and the effects were stronger when the stress levels increased. A three-way-interaction was also found among gender, stress, and extrasensory perception, with the moderation effects of extrasensory perception on stress and cold symptoms stronger for women than for men, and these effects becoming stronger as stress levels elevated. This study is an important step for understanding the relationships among gender, spiritual factors and cortisol levels under laboratory-induced stress. These results have implications for developing preventions or interventions that incorporate mindfulness practices and take extrasensory perception beliefs into consideration for stress reduction and health promotion. / Dissertation/Thesis / Ph.D. Counseling Psychology 2010

abstract: Current theoretical debate, crossing the bounds of memory theory and mental imagery, surrounds the role of eye movements in successful encoding and retrieval. Although the eyes have been shown to revisit previously-viewed locations during retrieval, the functional role of these saccades is not known. Understanding the potential role of eye movements may help address classic questions in recognition memory. Specifically, are episodic traces rich and detailed, characterized by a single strength-driven recognition process, or are they better described by two separate processes, one for vague information and one for the retrieval of detail? Three experiments are reported, in which participants encoded audio-visual information while completing controlled patterns of eye movements. By presenting information in four sources (i.e., voices), assessments of specific and partial source memory were measured at retrieval. Across experiments, participants' eye movements at test were manipulated. Experiment 1 allowed free viewing, Experiment 2 required externally-cued fixations to previously-relevant (or irrelevant) screen locations, and Experiment 3 required externally-cued new or familiar oculomotor patterns to multiple screen locations in succession. Although eye movements were spontaneously reinstated when gaze was unconstrained during retrieval (Experiment 1), externally-cueing participants to re-engage in fixations or oculomotor patterns from encoding (Experiments 2 and 3) did not enhance retrieval. Across all experiments, participants' memories were well-described by signal-detection models of memory. Source retrieval was characterized by a continuous process, with evidence that source retrieval occurred following item memory failures, and additional evidence that participants partially recollected source, in the absence of specific item retrieval. Pupillometry provided an unbiased metric by which to compute receiver operating characteristic (ROC) curves, which were consistently curvilinear (but linear in z-space), supporting signal-detection predictions over those from dual-process theories. Implications for theoretical views of memory representations are discussed. / Dissertation/Thesis / Ph.D. Psychology 2012

abstract: The U.S. Surgeon General has recommended that all Americans engage in regular physical activity throughout the lifespan as a way to maintain and improve health and reduce the risk of developing cardiovascular disease, diabetes, obesity, or other chronic conditions. The recommendation for children is a minimum of 60 minutes of moderate and intense physical activity everyday. As children enter adolescence their level of physical activity often decreases; and active adults were typically active adolescents. More than 50% of adults that begin a physical activity program discontinue the behavior within 9 months. Interventions to increase physical activity have looked at self-esteem and self-efficacy. Locus of control (LOC) is a concept that people either view their own behavior as influencing the events around them (internal) or other events controlling their fate or destiny (external). This study looked at locus of control as a predictor of exercise adherence and future exercise patterns in children ages 6-12 in Mesa, AZ. Locus of control as measured by the Child Nowicki-Strickland Internal External (CNSIE) scale differed by gender and by physical activity group at school at post-intervention. Self-reported physical activity as measured by the Physical Activity Questionnaire for Older Children (PAQ-C) showed differences in physical activity (PA) levels by gender for baseline school PA, by age group for baseline non-school PA, by gender and age group for post-intervention school PA, and by gender only for post-intervention non-school PA. A secondary objective was to assess if the Think Healthy About Nutrition and eXercise (THANX) after school program influenced participants' LOC or PA patterns. This study found that the THANX program had no effect on LOC or PA level at any time point. / Dissertation/Thesis / M.S. Exercise and Wellness 2012

abstract: Childhood obesity is associated with many well established health risks as well as high annual public health costs. Because of this, the childhood obesity literature has highlighted the need to detect at-risk groups in order to implement targeted preventions. Emotional eating has been identified as an unhealthy behavior and a risk factor for overweight status among children though very little is known about what predisposes children to emotionally eat. Stress has often been found to elicit emotional eating but most studies looking at this relationship have relied on self-reports in adult and clinical samples. Thus, the current study seeks to investigate the relationship between stress reactivity (measured using heart rate variability) and emotional eating in a sample of 247 children between the ages of 4-6. Furthermore, levels of control may moderate the relationship between stress reactivity (HRV) and emotional eating. Linear regression analysis was used to explore these relationships. It was expected that higher levels of reactivity to stress would predict an increased likelihood of emotional eating. This association was expected to be attenuated among children with higher levels of inhibitory control and attentional focusing as well as lower levels of impulsivity. However, the hypothesized findings were not supported by the data. Despite these null findings, and in light of several limitations, it is still hypothesized that emotional eating involves physiological and impulsivity/effortful control processes. Implications of future research are discussed. / Dissertation/Thesis / Masters Thesis Psychology 2016