Animal models can contribute significantly to our understanding of human gambling behavior. However, no proposed animal models of human gambling have been tested using human subjects. The purpose of the present paper was to validate an animal model of gambling with human subjects. Twenty undergraduate rehabilitation students (all women) were recruited and participated for extra course credit. Participants were presented with a concurrent choice between two different simulated slot machines; one machine with symbols and one machine without symbols. During the first 50 choice trials, the payout of the two machines was equated at 50% overall. For the remaining 50 choice trials, probability of winning on the machine with symbols was systematically decreased by 10% overall every ten trials until there was no probability of winning for the last ten trails. On average, participants showed a preference for the machine with symbols during choice trials when win rate was equated; allocating significantly more than 50% of responding to this machine. A repeated measures ANOVA indicated that response allocation to the symbol machine only significantly decreased in the final two conditions (10% and EXT) and did not decrease significantly across any other conditions. Results were also interpreted through behavioral economic analyses. Results indicate that conditioned reinforcement may affect the subjective value of probabilistic reinforcers in humans. These results are similar to those obtained with pigeons under similar conditions and may imply that animal models are relevant to the study of human gambling behavior.

The present study showed the impact of discounting across multiple populations that were obese to that of matched controls. The experiment used one decreasing hypothetical temporal procedure and three probabilistic health discounting procedures in which, of 38 participants interviewed, 20 were obese. It appears that age and obesity alter the subjective values of the delayed rewards within both temporal and probabilistic paradigms. The current data showed a significant difference between populations that were obese to that of the matched controls. In addition, statistically significance was found between the two obese populations within the study. Implications of the future of delay discounting are addressed, in addition to the stigma of delay discounting within behavior analysis.

The study examined how individuals make decisions on hypothetical sexual partners and hypothetical monetary rewards in delay and probability discounting. The participants (N-75, males=42 (M=34) and females=33(M=39)) completed an electronic survey via Qualtrics. The survey consisted of 6 tasks: 1. Multiple Stimulus without Replacement Preference Assessment that consisted of pictures of potential sex partners based on the individual’s gender preference (male, female, or both); 2. Sexual Risk Survey; 3. Monetary delay discounting task; 4. Monetary probability discounting task; 5. Delay discounting of hypothetical sexual partners; and 6. Probability discounting of hypothetical sexual partners. An analysis of area under the curve (AUC) were done for the discounting tasks. The results showed that males devalued delayed sexual partner choice rank higher rates than females (t (7.97) = 2.85, p<0.05). This was also observed in females with higher scores of the Sexual Risk Survey than the lower scorers (t (10.95) = 2.35, p<0.05). AUC reflected on the scores of the SRS and with measures of sexual risk behaviours. However, there were no significant difference in discounting monetary rewards between the genders (t (11.96) = 0.1623, p>0.05).

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.

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.

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

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

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.

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 delaydiscounting 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.