abstract: The value of safe sex may be discounted based on contextual factors associated with an opportunity for sex. College students (n = 75) in a within-subjects study selected hypothetical sexual partners from a set of pictures and classified them based on attractiveness and estimated chance of having an STI. In the sexual delay discounting (SDD) task, participants rated their likelihood (0 – 100%) of waiting for some period of time (e.g., 3 hours) to have protected sex with their selected partners, when they could have immediate sex without protection. In the sexual probability discounting (SPD) task, participants rated their likelihood of having protected sex if the opportunity was uncertain (e.g., 50%), when they could have unprotected sex for sure (100%). All participants included in the final analyses were aware of and had a positive attitude towards protection against STIs as they indicated preference for immediate (or certain) protected sex. Results show that participants’ willingness to have safe sex systematically decreased as the delay to and odds against having safe sex increased. However, these discounting patterns were observed only in some partner conditions but not others, showing that preference for delayed (or uncertain) safe sex was altered by perceived attractiveness and STI risk of sexual partners. Moreover, the hyperbolic discounting model provided good to acceptable fit to the delay and probability discounting data in most-wanted and least-STI conditions. Gender differences in devaluation of safe sex were also found. / Dissertation/Thesis / Masters Thesis Psychology 2016

abstract: Delay discounting is the decline in the present value of a reward with delay to its receipt. (Mazur,1987). The delay discounting task is used to measure delay discounting rate, which requires the participants to choose between two options: one involves immediate delivery of a reward, and other involves delivery after a delay, and the immediate rewards are adjusted in value until the subject feels there is no difference between the immediate and the delayed reward. Some previous studies (Robles and Vargas, 2007; 2008; Robles et al., 2009) found that the order of presentation of the immediate rewards (ascending or descending) significantly influenced the estimated delay discounting rate, which is known as the order effect. Uncertainty about the future and impulsivity could explain delay discounting behavior. The purpose of this study was to explore the order effect in delay discounting assessment. The current study found that the order effect in the delay discounting task can be explained by risk aversion, loss aversion and impulsivity. In the current study, the two kinds of fixed procedure (ascending and descending), and the titrating delay discounting task were used to estimate the degree of delay discounting. Also, two gambling tasks were applied to measure risk and loss aversion indices. The BIS-11 scale was used to assess the level of trait impulsivity. The results indicated that impulsivity biases individuals to choose the immediate small reward rather than the large delayed reward, resulting in lower area under the discounting curve (AUC) when estimated with the ascending-sequence delay discounting task. Also, impulsivity moderated the relationship between loss aversion and AUC estimated with the descending-sequence delay discounting task. / Dissertation/Thesis / Masters Thesis Psychology 2018

Why is it difficult to save for a pension or maintain a healthy diet? Choosing between options that have future or delayed consequences presents a challenge for a decision maker. When faced with such intertemporal choices the tendency to favour choices with immediate or short term outcomes, otherwise known as delay discounting, can lead to suboptimal consequences in the long-term. However, the mechanisms underlying the devaluation of future outcomes are poorly understood. This is due to the lack of a consistent framework for the representation of delays and delayed outcomes. One perspective is to represent delays as uncertainty. However, current conceptions of uncertainty are limited, by and large, to the dimension of probability, and are therefore inadequate. This thesis adopts a delay discounting model and emphasises different types of uncertainties within choice. Unifying these components, a framework that considers intertemporal choice as decision making under uncertainty is proposed. A series of behavioural and electrophysiological studies is presented to demonstrate that: it is the perceived uncertainty about 'if' and 'when' outcomes occur that contributes to behavioural discounting (chapters 2 and 3); the perception and evaluation of 'what' is delayed is underlined by emotional processes (chapter 4); and that generally, uncertainties about 'if' and 'what' outcomes differentially characterise risky and impulsive choices (chapter 5), and can be distinguished in terms of their informational qualities (chapter 6). Collectively, these findings present a deconstruction of uncertainty into components of 'if', 'what' and 'when', that could be mapped to delayed outcomes. I discuss them within the context of judgement and decision making, individual differences, and neural aspects of reward processing. These results allow me to argue that 1) all decision making is a process of information availability; 2) behaviour is motivated to reduce uncertainty; 3) choice is the manifestation of acquired information gathered from a decision-maker's internal and/or external environment. In conclusion, this thesis demonstrates that decision making under uncertainty can be qualified beyond a single dimension of probability; and that uncertainty can be characterised as a state of incomplete information about 'if' 'what' and 'when' outcomes will occur. Accordingly, intertemporal and risky choices can be accommodated within a single framework, subject to the same cognitive and neural processes. Consequently, this framework allows for the design of behavioural interventions that specifically target reducing uncertainties of 'if', 'what' or 'when'.

The study compared delay discounting in adult humans using two different methods of adjustments. Both methods used hypothetical choices of monetary outcomes. One involved adjustments using a fixed sequence of ascending or descending amounts, the other used a bisection algorithm in which the changes in amounts varied as a function of the subjects' choices. Two magnitudes of delayed outcomes were used: $1,000 and $10,000. A within subject design was used to compare indifference curves and discounting measures across the two adjusting procedures. Twenty four subjects were divided in two groups and exposed to the procedures in opposite order, to account for sequence effects. Results from within subject comparisons showed no systematic differences between procedures.

Brain injuries are one of the leading causes of disability and death globally, and prevalence numbers indicate an increase of injuries each year. Brain injuries significantly burden the individual afflicted; the effects of brain injuries are felt across families and relationships, and society at large. Brain injuries are often complicated by co-morbid socially significant health disorders, from mental health to financial and challenging behavior (i.e., aggression). The presence of these can severely limit access to community and rehabilitative opportunities. Some common characteristics underlying these socially significant problems are executive dysfunction and impulsivity. The literature broadly points to the role of executive functioning in impulsivity, indicating that when these processes are inadequate, impulsivity is more severe. To complicate, impulsivity research within brain injury is not broad. Additionally, little consensus exists on the concept and how stable this behavior is, and whether impulsivity can be improved. An area of impulsivity research, delay discounting, has gained increased attention from behavior scientists in the past 30 years because of its pragmatic approach to impulsivity. Delay discounting is a trans-disease process and various clinical populations discount delayed rewards at a high rate. The few studies that exist indicate that brain-injured people also discount at a higher rate compared to controls. Furthermore, high delay discounting have well-established connections with other socially significant health disorders. Due to the lack of breadth of the discounting literature in brain injury research, one exciting area is temporal stability and clinical interventions to decrease discounting. In a set of two studies, the aim was to expand the current knowledge on temporal stability, connections to socially significant behavior and deficits, and the effects on clinical interventions to reduce discounting. Study 1 examined the relationship between responses on discounting tasks at two different times and the relationship between discounting and measures of challenging behavior and executive functions. This study indicates that discounting was stable, that challenging behavior is related to higher rates of discounting yet did not find a relationship with executive functioning. Study 2 investigated the effects of computerized cognitive training and mindfulness training on discounting, executive functioning, and challenging behavior in multiple baseline research design across three participants. Results indicated that a small and transient improvement in delay discounting was observed for two of three participants during the computerized cognitive training. The improvement increased once the mindfulness training was introduced for the same two participants. Improvements were observed on executive functioning measures for all participants, and limited improvements were observed from measures of challenging behavior. Together these findings add to the body of literature on delay discounting and brain injury by demonstrating temporal stability and to the literature on clinical interventions to reduce high rates of delay discounting

Acceptance and Commitment Training (ACT) is a psychological intervention that combines acceptance and mindfulness approaches with behavior change strategies to increase psychological flexibility, defined as present moment awareness despite unpleasant private events, and behaving based on personal values. Obesity is a socially significant problem effecting duration and quality of life. Quantifying differences between high and low exercise groups and evaluating interventions that affect exercise value represent an avenue to understand obesity and change behavior. This study assessed the effects of a brief ACT exercise on the demand for general and sport-specific exercise and delay discounting rates of four commodities (i.e., money, food, general exercise, and sport-specific exercise) in Division I athletes (n=78) and non-athletes (n=78) from the same university. Statistically significant main effects for general exercise were observed between athletes compared to non-athletes for intensity, elasticity, and breakpoint. Differences in demand for sport-specific exercise between athletes and non-athletes were observed across all behavioral economic indices. The ACT intervention did not alter the demand for general or sport-specific exercise. General and sport-specific exercise were valued similarly between individual participants in each group. In the delay discounting task, ACT significantly decreased degree of discounting of all four commodities (increased the area under the curve) in both athletes and non-athletes. No differences were observed between athletes and non-athletes for any of the four commodities, indicating that athletes and non-athletes discounted these commodities similarly. Results from the demand task provide initial support for the extension of hypothetical purchase tasks to exercise behavior. which would offer a standardized method to quantify exercise value efficiently. Results from the discounting task provide initial evidence indicating that ACT may be effective in reducing discounting rates across commodities. Given that steep discounting rates are considered to play an important causal role in maladaptive behaviors related to obesity, evidence of a therapeutic intervention with the potential to produce longer-lasting change in decision-making is encouraging.

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The purpose of the current study was to examine an ACT based intervention and its effects on problem behaviors and impulsivity rates displayed by individuals diagnosed with Mild Intellectual Disabilities. In a multiple baseline design with 2 experiments, 6 participants completed the 27-item monetary choice questionnaire weekly throughout the 9-week study. Impulsivity rates were calculated, and behavior data was collected throughout each phase of the study. During the intervention phase of the study brief ACT sessions were conducted 3 times a week during one-on-one sessions with each participant. Sessions were held face-to-face or via phone call. A stacked multiple baseline design was computed, and the data was inputted, indicating that ACT may effectively reduce problem behaviors in participants diagnosed with Mild Intellectual Disabilities. The current study suggests that ACT interventions have no effect on impulsivity. Implications of the findings and future research are discussed. Keywords: ACT, Impulsivity, Delay Discounting, Intellectual Disability, Monetary Choice Questionnaire

The present study aimed to evaluate (a) the extent to which different impulsivity measures would be related to each other and to a risk taking measure, (b) the extent to which impulsivity, risk taking, time perception and time perspective are related to each other, and (c) the extent to which these processes differ in Latino and White American students. Experiment I was conducted at Utah State University. One hundred and fortythree participants were exposed to the delay discounting, probability discounting and temporal bisection procedures, and answered the Barratt Impulsiveness Scale (BIS-11) and the Zimbardo Time Perspective Inventory (ZTPI). Results showed that (a) the AUC for delay discounting was related to the scores on the BIS-11 scale, (b) the AUCs for delay and probability discounting were positively and significantly correlated, (c) the mean of the temporal bisection procedure was correlated with the AUC of the delay discounting procedure, (d) the scores on the ZTPI were correlated with the impulsivity measures, and (e) the scores on the ZTPI subscales were also correlated with the risk taking measure. These results suggest that different impulsivity measures may be evaluating similar decision-making processes, that impulsivity and risk taking may be different decision- making processes, and that time perception and time perspective are related to impulsivity and risk taking. Experiment II was conducted at Washington University in St. Louis, with 18 Latinos and 16 White Americans. Results show that while Latinos were more impulsive in the delay discounting procedure, their scores did not differ from the White Americans on the BIS-11. Interestingly, Latinos and White Americans did not differ on time perception, but they did differ on time perspective: Latinos scored higher on fatalism compared to White Americans.

Many problematic behaviors can be conceptualized as choosing a smaller, immediate outcome over a larger, delayed outcome. For example, drug abuse involves choosing between the immediate euphoric effects of the drug and the delayed health and legal consequences of drug abuse. Individuals that consistently choose the smaller outcome are said to behavior “impulsively.” The goal of this dissertation was to understand how to change impulsive choice. Chapters 2 and 3 successfully demonstrate that impulsive choice can be altered by reframing how the choice is presented. For example, framing a delayed outcome using a specific date instead of a duration of time (e.g., 1 year) reduced impulsive choice. However, these findings do not explain why impulsive choice changed. The goal of Chapter 4 was to identify the underlying processes that result in impulsive choice with the hopes that by understanding these processes, impulsive choice can be reduced. Latent factor modeling was used to understand the role if three proposed processes in impulsive choice: marginal utility, cardinal utility, and nonlinear time perception. The results of the latent factor model indicated that nonlinear time perception does relate to how delayed outcomes are valued but not marginal utility and cardinal utility.