Externalizing behaviors have been shown to exhibit within-individual changes, increasing the need to identifying factors that influence such behavior to be more or less likely to occur in any given moment. The current study aimed to contribute to the understanding of mechanisms that influence externalizing behavior using an intensive longitudinal design. Demographic variables and personality traits were measured at baseline. Momentary personality states, situational context, affect, decision-making processes, and externalizing behaviors were measured three times per day for seven days in a university sample (N = 170). Results: A new measure of momentary externalizing—Momentary-Externalizing Spectrum Inventory—was created as a practically feasible measure to administer multiple times per day and its psychometric properties were investigated. Trait disinhibition-versus-constraint predicted mean levels of externalizing behaviors. Results supported the incremental utility of personality states, such that they appear to offer additional predictive power for momentary externalizing behavior over and above personality traits. Candidate proximal mechanisms such as situational factors, momentary affect, and delay discounting were shown have the ability to predict momentary externalizing behavior in an ongoing temporally varying manner. Personality traits moderated some of these relationships between candidate proximal mechanisms and momentary externalizing behavior. Implications for the understanding of externalizing behaviors were discussed while hypotheses for future research were generated.

In dieser Studie führten 37 adulte Patienten mit einer Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) ein Delay Discounting (DD) - Paradigma aus, während gleichzeitig mittels Funktioneller-Nahinfrarotspektroskopie (fNIRS) die Gehirnaktivität der „Regions of Interest“ (ROIs) des Orbitofrontalen-Kortex (OFC) und des Dorsolateralen-Präfrontalen-Kortex (dlPFC) gemessen wurde. Mittels Fragebögen und eines Delay Discounting Tasks (DDT) wurden zusätzlich Verhaltensparameter erhoben und flossen in den Auswertungsprozess mit ein. Vorausgegangene Untersuchungen weisen auf ein hypofunktionel-les dopaminerges System bei ADHS-Patienten hin, welches mit der ADHS-Pathogenese in Zusammenhang gebracht wird. Vor allem im Präfrontalen-Kortex (PFC), bestehend unter anderem aus OFC und dlPFC, erfolgt die Metabolisierung von Dopamin durch die Catechol-O-Methyltransferase (COMT). Hierbei hängt die Metabolisierungsgeschwindigkeit vom genetischen COMT-Val158Met- Polymorphismus ab. Die Einflussnahme dieses COMT-Val158Met-Polymorphismus auf die kortikale Aktivität der ROIs und Impulsivität ist ebenfalls Gegenstand dieser Dissertation („Imaging Genetics“). Adulte ADHS Patienten zeigten eine verstärkte Aktivität des OFC der Entscheidungskategorie „verzögert“ im Verhältnis zu der Entscheidungskategorie „sofort“. Die gemessene Impulsivität korrelierte mit der kortikalen Gehirnaktivität „DD-Kontrast“. Es konnte kein Zusammenhang zwischen Verhaltensparameter und Gehirnaktivität mit dem COMT-Polymorphismus gezeigt werden. Die erhöhte Aktivität des OFC bei der Entscheidungskategorie verzögert unterstützt die These der „Delay Aversion“ des „Dual Pathway Model“. Eine enge Konnektivität der stark dopaminerg innervierten kortiko-striataler Strukturen in Form des OFC und der Amygdala, welche Einfluss auf die ADHS-Pathogenese nehmen, erscheint somit plausibel. / In this study 37 adult subjects with ADHD (Attention Deficit Hyperactivity Disorder) performed a validated Delay Discounting (DD) paradigm. By using near-infrared-spectroskopy (NIRS) functional brain activation in the regions of interest (ROIs) was measured. The ROIs are represented by the Orbito-Frontal-Cortex (OFC) and the Dorsolateral Prefrontal Cortex (dlPFC). Additionally questionnaires with relation to behaviour and a Delay Discounting Task (DDT) were interpreted. Former studies indicate a hypo-functional dopaminergic system in ADHD pathology. Mainly the Prefrontal Cortex (PFC), including the OFC and the dlPFC, metabolizes dopamine with the Catechol-O-Methyltransferase (COMT). Velocity of this metabolism depends on the COMT-Val158Met-polymorphism. This effect is generally known by the term “imaging genetics”. Adult ADHD subjects showed a stronger activation in the OFC in the DD category “delayed” than in the category “now”. Measured impulsivity correlated with the cortical brain activity “DD-Kontrast”. No significant relation between the COMT polymorphism an the cortical brain activity or behaviour could be shown. The stronger activation of the OFC in the category “delayed” underlines the thesis of “Delay Aversion” from the “Dual Pathway Model”. A close connectivity between the dopaminergic corticostriatal brain regions of the amygdala and the OFC, which have an influence to the ADHD pathology, seem to be a plausible approach.

Personal investors must postpone gratification and manage risk. This thesis examines the effects of delay and risk on personal investment decisions. The delay discounting literature is employed in developing a new parameter �ki� which integrates an investment�s term and interest rate with the hyperbolic delay discounting model. By indicating the extent to which compound interest growth compensates for hyperbolic delay discounting, ki should strongly predict the subjective appeal of prospective investment returns. Six binary-choice experiments test this hypothesis, especially via a subsidiary hypothesis that exponential growth from compound interest will eventually compensate for delay, given a sufficient term. Analyses include a novel application of signal detection principles, which found ki a superior predictor of investment appraisals compared to the normative exponential delay discounting model. Subject to boundary conditions of term and investment amount, results support the predictive capacity of ki for gross returns, implying a hitherto unrecognised degree of predictability for investment decisions. To investigate perceptions of risk with delay, three additional experiments compared preferences among hypothetical investments with varying risk and term. Risk seeking and risk aversion were detected, consistent with individual differences in hyperbolic probability discounting rates. Excessive risk aversion proved the greater problem, encouraging unnecessarily conservative investment decisions. Unexpectedly, no evidence of delay discounted risk was found. Responses consistent with higher probability discounting of larger amounts occurred, but only for a longer rather than a shorter investment term. A survey of postgraduate finance students examined how investment past performance is interpreted. Participants evaluated annual returns from hypothetical 10-year investments that varied in their mean return, volatility, and sequence of high and low returns. Evaluations generally reflected underlying investment properties. Maladaptive appraisal tendencies included unwarranted attention to the order in which high and low returns occurred within a series. Overall for this dissertation, results suggest that delay and probability discounting theory has practical relevance for understanding personal investment decisions. The principles and methodology in this dissertation are applicable to other varieties of financial and consumer behaviour.

Delay discounting, the belief that rewards decline in value over time, is a phenomenon observed in several clinical disorders, including Attention Deficit / Hyperactivity Disorder (ADHD), substance abuse disorders, and other impulse control disorders. Delay discounting behavior is characterized by a tendency to choose smaller, more immediate rewards over larger, more delayed rewards. This tendency has been associated with behavioral impulsivity and inability to delay gratification observed in the aforementioned clinical disorders. It has been suggested that time perception may be a salient feature of delay discounting. If the larger, longer-term reward is perceived as being more temporally remote, its relative value decreases and is associated with greater cost, and one becomes more likely to choose the more immediate reward over the longer-term (though optimal) choice. Time perception has been studied in clinical populations, with increased variability of responses as well as both under-production and overestimation of time intervals observed in those with ADHD and other disorders associated with impulsivity. The present study used informational feedback via a metronome to change belief regarding duration of a second--either increasing or decreasing it by approximately 20%. Participants were 132 college-aged students with and without a diagnosis of ADHD. Measures of impulsivity and ADHD symptomatology were collected as well, and participants completed several cognitive tasks measuring working memory and processing speed to explore the impacts of these measures on delay discounting and time perception. While participants were able to reliably incorporate the altered second belief into short estimations of time (i.e., less than a minute), the manipulation failed to generalize to longer-duration temporal estimations, and it did not affect delay discounting. Neither ADHD symptomatology, impulsivity, nor performance on the cognitive tasks were related to delay discounting behaviors, though a working memory measure was correlated with baseline (pre-manipulation) time and one longer duration estimation. This lends support to a relationship between working memory and temporal perception, though the relationship between temporal perception and delay discounting remains elusive. Directions for future studies to clarify the role of temporal processing and ADHD in delay discounting are discussed. / text

Problem and pathological gambling has become an increasing public health concern worldwide in recent years, and individuals from China and East Asian countries may be especially vulnerable. Knowledge of how individuals make choices between outcomes that are delayed or uncertain, and of potential differences in decision making across cultures, may contribute to our understanding of factors which increase the risk of problem gambling. Our research is based on a discounting perspective in which the value of a delayed or uncertain reward decreases according to the time until or the odds against its receipt, respectively. We use experimental procedures in which individuals make a series of hypothetical choices so as to estimate an indifference point – an amount of money available immediately or with certainty – that is equal in subjective value to a delayed or uncertain reward. Our starting point is the hypothesis that reward contrast – in which the subjective value of a reward varies inversely with amount of a prior reward – plays a role in choice between delayed or probabilistic outcomes and might contribute to problem gambling. This thesis describes four experiments which investigate these ideas. Experiments 1 and 2 establish that reward contrast is a reliable phenomenon in choice. Indifference points for an intermediate reward ($475/$525) varied as predicted if its subjective value was larger when the individual had previously been making choices with a smaller amount ($50) and smaller when previously making choices with a larger amount ($5,000). Reward contrast was obtained for both delayed and probabilistic choice, using between-subjects (Experiment 1) and within-subjects (Experiment 2) designs. Experiment 3 used a computerized Card Playing Game (CPG) as an analogue gambling task and also measured delay discounting using the same task as Experiment 2. Participants began with an initial stake and could win or lose 10% of the stake with each card that they played. The critical aspect of the procedure was that the probability of winning for each card decreased as more cards were played. Participants played the CPG four times with stakes of $50, $500, $5,000 and $500 (order of $50 and $5,000 was counterbalanced). Results showed that performance on the CPG improved over successive trials, suggesting that participants learned the contingencies in the task. Although this confounded our attempt to measure reward contrast within-subjects, participants who had a $50 stake in the first deck performed better in the second deck with a $500 stake than those who had a $5,000 stake in the first deck, consistent with reward contrast. Results from the delay discounting task were correlated with CPG performance, showing that participants who had lower reward contrast and discounting rates, and greater magnitude effects won more money on the CPG task. Experiment 4 used a larger sample (N = 182) with both Chinese and Caucasian (New Zealand European) participants and recruited individuals with gambling histories, and compared performance on delay and probability discounting tasks and the CPG. Results showed that Chinese participants had higher delay discounting rates and lower probability discounting rates when data were analyzed according to the area under the discounting curve (AUC). Gamblers (those participants with scores on the South Oaks Gambling Screen [SOGS; Lesieur & Blume, 1987] > 1) were less risk averse in probability discounting and had reduced magnitude effects in delay discounting and performed more poorly on the CPG. Closer analysis of the probability discounting data showed that compared with Caucasians, Chinese were more risk averse for high probabilities of reward outcome, and less risk averse for low probabilities. Although results do not suggest that individual differences in reward contrast, as measured using our within-subjects delay discounting task, play a significant role in the maintenance of gambling behavior, the cross-cultural differences in delay and probability discounting in Experiment 4 suggest some factors that might contribute to gambling. In the General Discussion, we propose an account of the probability discounting results in terms of a tendency toward dialectical thinking and emotions in Chinese culture. Based on this result and previous research, we propose a framework for the cross-cultural analysis of risky decision making, and consider some of its broader implications for both research in decision making and issues of globalization.

Personal investors must postpone gratification and manage risk. This thesis examines the effects of delay and risk on personal investment decisions. The delay discounting literature is employed in developing a new parameter �ki� which integrates an investment�s term and interest rate with the hyperbolic delay discounting model. By indicating the extent to which compound interest growth compensates for hyperbolic delay discounting, ki should strongly predict the subjective appeal of prospective investment returns. Six binary-choice experiments test this hypothesis, especially via a subsidiary hypothesis that exponential growth from compound interest will eventually compensate for delay, given a sufficient term. Analyses include a novel application of signal detection principles, which found ki a superior predictor of investment appraisals compared to the normative exponential delay discounting model. Subject to boundary conditions of term and investment amount, results support the predictive capacity of ki for gross returns, implying a hitherto unrecognised degree of predictability for investment decisions. To investigate perceptions of risk with delay, three additional experiments compared preferences among hypothetical investments with varying risk and term. Risk seeking and risk aversion were detected, consistent with individual differences in hyperbolic probability discounting rates. Excessive risk aversion proved the greater problem, encouraging unnecessarily conservative investment decisions. Unexpectedly, no evidence of delay discounted risk was found. Responses consistent with higher probability discounting of larger amounts occurred, but only for a longer rather than a shorter investment term. A survey of postgraduate finance students examined how investment past performance is interpreted. Participants evaluated annual returns from hypothetical 10-year investments that varied in their mean return, volatility, and sequence of high and low returns. Evaluations generally reflected underlying investment properties. Maladaptive appraisal tendencies included unwarranted attention to the order in which high and low returns occurred within a series. Overall for this dissertation, results suggest that delay and probability discounting theory has practical relevance for understanding personal investment decisions. The principles and methodology in this dissertation are applicable to other varieties of financial and consumer behaviour.

abstract: Research in the area of childhood trauma has shown a substantial amount of psychological maladjustment following the experience of traumatic events in childhood. Trauma survivors are at risk for developing a multitude of adverse psychological outcomes as well as unsafe behaviors following the event of trauma. One unifying theme within these psychological sequelae is the nature of impulsive behaviors. Delay-discounting refers to the subjective decrease in value of a reward when its presentation is delayed. Delay-discounting is often used as an index of impulsive behavior. This study poses two primary questions: 1) Can childhood trauma predict rates of delay-discounting? 2) Could delay-discounting predict psychological maladjustment for individuals who have experienced childhood trauma? This study will seek to answer these questions using an online version of the Kirby et al., 1999 hypothetical delay-discounting method, as well as the Barratt Impulsiveness Scale (BIS-11), to measure trait impulsivity. Measures of depression (BDI-II), life events (LEC), post-traumatic stress (PCL-C), and drug and alcohol abuse (DAST-20) will also be included. Participants included a sample of university students ages 18-52 (n=521, females = 386, males = 135) with a mean age of 25.19 years. Results indicated that childhood trauma was not a significant predictor of delay-discounting rate, nor was delay-discounting rate a significant predictor of psychological maladjustment. Limitations and future directions are discussed. / Dissertation/Thesis / M.S. Psychology 2012

TITLE: IMPULSIVNENESS AND SELF-REOPRTED VALUES MAJOR PROFESSOR: Dr. Mark R. Dixon Towards developing an applied behavior technology that treats vales as the dependent variable of interest, there is a necessity for understanding the relationship between impulsiveness and self-reported values. The purpose of this study was to evaluate how values affected social and delay discounting. Thirty participants were given two surveys, one was a social discounting survey, and the other was a delay discounting survey. Finally, participants were given a valued-living questionnaire. In the social discounting survey, participants were asked to mentally make a list of people they knew from 1-100, 1 being the closest to them and 100 being a distant acquaintance. They were then asked to pick between two choices involving hypothetical money. Starting with the choice of keeping $85 for themselves, or giving $75 to the 1st person on their list. The second choice was to keep $75 for themselves, or give $75 to the #1 person on their list. The monetary value continued to decrease by 10, while the value to give to another person remained the same, these were continued for person #2, # 5, #10, #20, and #50 on their list. The delay discounting instructed participants to choose between two hypothetical choices. The first was receiving $85 today or $75 in 1 week. The second choice was to receive $75 today, or $75 in 1 week. The hypothetical monetary value was decreased by $10, until it reached $5. The valued living questionnaire used a Likert-scale from 1-10 with 1 being ‘not at all important and ’10 being ‘extremely important’ across 10 areas (family-other than marriage or parenting, i marriage/couples, intimate relations, parenting, friends/social life, work, education/training, recreation/fun, spirituality, citizenship/community life, and physical self-care (diet, exercise, sleep). The second section of the questionnaire evaluated committed action, and asked participants to rate how consistent their actions have been with each of these value areas within the past week. A Likert-scale was also used from 1-10, with 1 being ‘not at all consistent with my value’ and 10 being ‘completely consistent with my value’. A Pearson product-movement correlation coefficient was composed to access the relationship between the switch point of discounting and rating of each area of valued living. There were to valued living areas with significant findings. There was a positive correlation between Social AUC and VLQ: Importance- Social/Friends (r=.503, n=30, p=.005). There was also a positive correlation between Delay AUC and VLQ: Importance- Physical self-care (r=.448, n=30, p=.013). There was no correlation between either social AUC and delay AUC and any of the committed action values. The results have implications for a translational understanding of the influence of discounting on reported values and committed action processes.

The present study examines delay, probability, and social discounting with money in relations to self-reported values. The participants completed a values questionnaire including questions regarding God, sex, and politics, and were divided into a low values and a high values group with the low values group n=10 and high values group = 10 for a total n=20. These groups were compared in the delay, probability, and social discounting tasks. Results indicate little to no difference in discounting between groups with an AUC for the low values group (.47), (.322), (.196), respectively and the AUC for the high values group at (.494), (.411), (.288) respectively. Individual scores for area under the curve (AUC) were tested for degree of correlation to each values question. Results indicate moderate correlations between temporal discounting and 5 sex value questions. Moderate correlations between probability discounting and political and sex value questions were observed. Finally, correlations between social discounting and politics, religious, and sex values were observed. Keywords: delay discounting, probability discounting, social discounting, politics, sex, religion

The present study used healthy questionnaires to evaluate the compounding effects of weight loss and weight gain in choosing to exercise. The questionnaire was distributed to 31 participants via social media outlets. Demographic information was also recorded such as height, weight, ethnicity, and income. The height and weight recorded was used to correlate the BMI with the AUC values. This data did not show a strong correlation between body mass index with high or low AUC values, these values were evenly distributed between underweight, normal/average weight, and overweight participants. . The questionnaires designed to assess how people view exercise and to determine if there is a pattern with sequencing delays with the calculated switch point and AUC. Statistical and visual analyses were conducted at the group and participant level. The switch points, were documented from each delay and was calculated to determine the compounding sequence that was preferred from each participant. The results from the study indicated that participants chose to exercise immediately within the first day, when the consequence was to lose weight. The results for the gain condition indicated that participants would gain weight instead of exercise, to a certain limit (100 days), when they chose to then engage in exercise behavior regularly. The conclusion of this study shows that the longer the delay the less valued the outcome is. This is important when understanding the obesity epidemic within the United States.