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Current neurobiological models of adolescent decision-making suggest that heightened risk taking during adolescence is a result of the asynchronous development of neural regions underlying cognitive control and reward processing, particularly during periods of heightened social and affective arousal (e.g., Casey, Getz, & Galván, 2008; Steinberg, 2008). Despite the emphasis on the interplay of cognitive and emotional processes during adolescence, the developmental literature has largely overlooked the potential importance of maturational changes in the anterior insular cortex (AIC), a region known for its role as a cognitive-emotional hub. In a recent review we proposed a theory of adolescent risk-taking in which development of the AIC, and its connectivity to other regions, biases adolescents towards engagement in risky behaviors (Smith, Steinberg, & Chein, 2014b). The current studies provide a test of the proposed model through an examination of specific aspects of AIC development and functioning, including the trajectory of structural development within the AIC, the role of AIC engagement in adolescents' risky decision-making, and the impacts of affective arousal on AIC recruitment. Results from Study 1 suggest that the AIC exhibits continued developmental changes during adolescence that likely affect its involvement in cognitive processes. Using a risk-taking task, Study 2 demonstrates the flexible role of the AIC during adolescent decision-making and explores how affective arousal biases the AIC towards engagement in risky behaviors. Implications for both the proposed model and the developmental literature are discussed. / Psychology

Individuals with borderline personality disorder (BPD) and high levels of BPD traits have demonstrated greater rates of engagement in risky, self-destructive behaviors compared to healthy controls. Specifically, impulsivity has been theorized to underlie many of these risky behaviors. Although existing self-report literature suggests that individuals with BPD are more impulsive than controls, evidence from behavioral measures remains inconclusive. Likewise, there is scant research examining specific domains of impulsivity associated with risky behaviors in BPD, which is problematic given that impulsivity is a diagnostic criterion for BPD. Thus, the proposed research aims to bridge this gap in the literature by examining associations between BPD traits and domains of impulsivity (e.g, urgency, lack of premeditation, lack of perseverance, and sensation seeking), using behavioral measures. Findings suggest that urgency prospectively predicts risky behaviors one-month post assessment. However, contrary to our hypotheses, BPD traits were not significantly associated with any specific impulsivity domain. Additionally, results did not support the notion that impulsivity domains account for the association between BPD traits and future engagement in risky behaviors. Future directions for examining how emotion dysregulation and interpersonal difficulties in BPD relate to impulsivity and risky behaviors are discussed.

Adolescence is a critical developmental period characterized by neurobiological changes and exposure to novel experiences. According to the Center for Disease Control, approximately 70% of adolescent deaths in the United States are due to risky behaviors such as reckless driving and risky sexual behavior (Kann et al., 2016). In order to better understand what drives adolescent risk-taking, the current studies utilized an interdisciplinary approach, which combined behavioral economic models and functional magnetic resonance imaging (fMRI) to understand neurobehavioral mechanisms of risky choice. The focus of the current studies is to investigate the extent to which neurobehavioral mechanisms of risky choice change across adolescence, and to identify individual differences that explain real-world risky behavior. In Study 1, we show that behavioral sensitivity to risk and neural correlates of risk processing change across a critical period of adolescence. Importantly, our results indicate that individual differences in neural, not behavioral risk sensitivity are predictive of future engagement in health risk behaviors. In Study 2, we examined the relation between inter-individual differences in adolescent expectations of valued rewards and self-reported risky behavior using an adapted behavioral economic model. Implications and future directions for adolescent risky decision-making are discussed. / Ph. D.

Economic preferences are fundamental to risky decision making and other economic decision- making. Unlike traditional economics, which routinely assumes that individuals are endowed with stable preferences and try to maximize the expected utility when facing risky decision-making problems, behavioral economics and neuroeconomics offer research strategies that help us explore the factors that influence economic preferences and risky decision-making process. This dissertation consists of three essays studying the underlying experiential influences on economic preferences and neurobiological effects on risky decision making. Chapter 2 examines whether experiences during adolescence have a long-term effect on economic preferences. Between 1966 and 1976, China's Sent-Down Movement required seventeen million urban teenagers to spend several years living and working in rural areas. The program had a number of goals for participants, including learning empathy for rural laborers and developing collectivist values. The sent-down movement can be regarded as a natural experiment, which allows us to investigate whether this government policy was successful in effecting a lasting change to economic preferences. Using a modified Global Preference Survey and employing a regression discontinuity design, we find that the experience of being Sent-Down significantly changed participants' risk preferences, other-regarding preferences, and attitudes toward government. Chapter 3 explores how the arousal system modulates attention and investment behavior. Experimental research shows that human decision making is shaped by emotions associated with an outcome's success or failure. Regret, for example, is a powerful predictor of future investment decisions in asset markets. Using a fictive learning model to capture regret, we examine changes in pupil diameter of participants performing a sequential investing task. By manipulating task uncertainty, we show that pupil dilation is positively correlated with both asset price variance and regret. In addition, pupil linked arousal is positively associated with the learning rate. We conclude that the pupil–linked arousal system helps regulate investment behavior in a dynamic market environment. Chapter 4 explores the complex process by which people make risky choices. While traditional models, like expected utility theory, model choice as the selection of the outcome with the highest probability-weighted value, research shows that in some environments these models do a poor job of describing behavior. This study explores the role of attention, pupil-linked arousal, and salience in risky choice. First, we replicate earlier findings that those choices are consistent with expected utility theory when the calculation is easy, however, as the calculation becomes harder, they make decisions by comparing unweighted payoffs and are attend to the salient option. Further, we find that pupil-linked arousal is associated with the level of cognitive effort needed to calculate expected utility. Finally, we show that arousal reflects cognitive effort associated with resisted selecting a more salient option. / Doctor of Philosophy / Economic decisions are those involving trade-offs where an individual must give up one item or possibility to get another. Economic preferences define which outcome an individual will value more, and helps explain why, for example, some people invest their money in high-risk and high- yield bonds while others keep their money in their savings account. Economists and other social scientists are interested in the differences between individuals' economic preferences, how they are formed, and how they translate into peoples' decisions. Risky decision making is one common type of economic decision that people make daily, for example, investing in the stock market, gambling in casinos, buying lottery tickets or trying a new restaurant. We know that when two people make different decisions that sometimes it is because they have different preferences, and sometimes it is because they go about making decisions in different ways. This dissertation explores whether people's early experiences have a long-term impact on economic preferences (Chapter 2), and investigate the roles that attention, emotional arousal, and information salience play in risky decision making (Chapters 3 4) using research methods from behavioral economics, experimental economics, and neuroeconomics. The scientific mission of this dissertation is to deepen our understanding of how and why people make choices. We add to the evidence that economic preferences are not inborn and stable; instead, they are shaped by people's experiences. We also explore risky choices like investing money and find that while people often try to minimize regret, our emotional arousal system significantly affects our attention patterns and behavior. In addition, when faced with decisions requiring calculations that are hard to do in your head, people make different decisions than when the calculations are easy. Overall, we paint a picture of human decision-makers whose past experiences and current options determine both the nature of their choices and how they make them.

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Thesis (MA)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The primary objective of the study was to determine the level of self-reported sexual risk behaviour of student men who have sex with men at a South African higher educational institution. The secondary objective was to determine the level of Human Immunodefiency Virus (HIV) knowledge among student men who have sex with men, and lastly to determine the extent to which the theory of planned behaviour is applicable in explaining intentions to use condoms. A sample of fifty student men who have sex with men were recruited to take part in an online baseline and follow-up survey, three months apart. Many of the student men who have sex with men reported sexual behaviour, which may place them at risk of contracting HIV. More than fifty percent (56%) had used alcohol or drugs during sexual intercourse in the past. Six percent (6.1%) reported having been forced to have sexual intercourse against their will. While 8% had experienced abuse and violence on campus, 22% had experienced abuse only and another 6% reported having experienced some form of violence due to their sexual preference. Most participants (70%) reported having used condoms almost always or always when engaging in penetrative sexual behaviours, but 30% had used condoms inconsistently or not at all in the past. The sample of student MSM scored high on a questionnaire of basic HIV knowledge, with a mean score of 14.57 (80.94%). The present study questions the applicability of the theory of planned behaviour in understanding and predicting intention to use condoms among a sample of student men who have sex with men attending a South African higher education institution. Only two of the major theoretical variables, namely attitude and perceived group norms, could significantly predict intention to use condoms. Attitudes regarding condom use were found to have an inverse The primary objective of the study was to determine the level of self-reported sexual risk behaviour of student men who have sex with men at a South African higher educational institution. The secondary objective was to determine the level of Human Immunodefiency Virus (HIV) knowledge among student men who have sex with men, and lastly to determine the extent to which the theory of planned behaviour is applicable in explaining intentions to use condoms. A sample of fifty student men who have sex with men were recruited to take part in an online baseline and follow-up survey, three months apart. Many of the student men who have sex with men reported sexual behaviour, which may place them at risk of contracting HIV. More than fifty percent (56%) had used alcohol or drugs during sexual intercourse in the past. Six percent (6.1%) reported having been forced to have sexual intercourse against their will. While 8% had experienced abuse and violence on campus, 22% had experienced abuse only and another 6% reported having experienced some form of violence due to their sexual preference. Most participants (70%) reported having used condoms almost always or always when engaging in penetrative sexual behaviours, but 30% had used condoms inconsistently or not at all in the past. The sample of student MSM scored high on a questionnaire of basic HIV knowledge, with a mean score of 14.57 (80.94%). The present study questions the applicability of the theory of planned behaviour in understanding and predicting intention to use condoms among a sample of student men who have sex with men attending a South African higher education institution. Only two of the major theoretical variables, namely attitude and perceived group norms, could significantly predict intention to use condoms. Attitudes regarding condom use were found to have an inversrelationship with intention to use condoms. The results from the hierarchical multiple regression analyses revealed that the linear combination of the theory of planned behaviour variables could significantly account for 68% of the variance in intention to use condoms when the predictors were considered together. Interventions that seek to lessen HIV risk behaviour among student men who have sex with men should endeavour to incorporate elements which should aim to augment perceived subjective norms regarding condom use. The findings advocate for additional research to be undertaken on the applicability of the theory of planned behaviour in informing health communication and sexual health interventions that aim to reduce HIV transmission risk among student men who have sex with men at higher educational institutions. / AFRIKAANSE OPSOMMING: Die primêre doel van die studie was om die vlak van self-gerapporteerde seksuele risiko gedrag van studentemans wat seks beoefen met mans (MSM) by 'n Suid-Afrikaanse hoër onderwysinstelling te bepaal. Die sekondêre doel was om die vlak van kennis oor die Menslike Immuniteitsgebreksvirus (MIV) onder studente MSM te bepaal, en laastens om die mate waarin die teorie van beplande gedrag toepaslik is om die voorneme om kondoom gebruik te verduidelik. ʼn Steekproef van vyftig studente MSM was gewerf om aan ʼn aanlyn basislynopname en opvolgopname deel te neem. Talle van die studente MSM het seksuele gedrag gerapporteer wat die mans blootstel aan die risiko om MIV op te doen. Meer as vyftig persent (56%) het in die verlede alkohol of dwelms gebruik tydens seksuele omgang. Ses persent (6,1%) het gerapporteer dat hulle al gedwing is om seksuele omgang teen hul wil te hê. Terwyl agt persent mishandeling en geweld op kampus ervaar het, het 22% slegs misbruik ervaar en nog 6% het een of ander vorm van geweld ervaar as gevolg van hul seksuele voorkeur. Die meeste deelnemers (70%) het gerapporteer dat hulle tydens penetratiewe seks byna altyd kondome gebruik, maar 30% het óf glad nie, óf ongereeld in die verlede kondome gebruik. Die studente MSM wat aan die steekproef deelgeneem het, het hoë tellings behaal in ‘n vraelys oor basiese MIV-feite, met ' ʼn gemiddelde telling van 14.57 (80.94%). Die huidige studie bevraagteken die toepasbaarheid van die teorie van beplande gedrag om die voorneme om kondome te gebruik onder ’n steekproef van studente MSM aan ’n Suid-Afrikaanse hoër onderwysinstelling te verstaan en te voorspel. Slegs twee van die belangrikste teoretiese veranderlikes, naamlik houding en subjektiewe groepnorme, kon beduidend die voorneme voorspel om kondome te gebruik. Houding oor kondoom gebruik het ʼn omgekeerde verwantskap met die voorneme om kondome te gebruik voorspel. Die resultate van die hiërargiese meervoudige regressie-ontleding het aangedui dat, wanneer die voorspellers saam oorweeg word, die lineêre kombinasie van die teorie van beplande gedrag veranderlikes betekenisvol tot 68% van die variansie in die voorneme om kondome te gebruik kan verklaar. Ingrypings wat daarop gemik is om MIV-risiko gedrag onder studente MSM te verminder, behoort elemente in te sluit wat streef daarna om waarneembare subjektiewe norme rakende kondoomgebruik aan te vul. Die bevindinge wys dat addisionele navorsing oor die gebruik van die teorie van beplande gedrag in gesondheidskommunikasie en seksuelegesondheid intervensies wat daarop gemik is om die risiko van MIV-oordrag tussen studente MSM by inrigtings vir hoër onderwys te verminder nodig is.