The effect of episodic future thinking on delay discounting

<p>Delay discounting refers to the fact that rewards lose their value if they are delayed. Excessive delay discounting is associated with various health-related problems such as over-eating and substance abuse. One phenomenon shown to reduce delay discounting is Episodic Future Thinking (EFT; imagining personal future events). Across multiple experiments and a meta-analysis, the current thesis examined the reliability of the effect of EFT on delay discounting and also sought to clarify the components of EFT that are necessary to reduce delay discounting. Experiment 1 replicated the EFT effect using a common titrating-amount procedure, and the meta-analysis based on 40 independent studies confirmed that EFT has a reliable, medium-sized effect on delay discounting. The meta-analysis also assessed the robustness of the EFT effect across various methodological features and participant characteristics. A multiple meta-regression revealed that the between-study variability in the size of the EFT effect was accounted for by study design and type of discounting measure. Within-subjects design studies had significantly smaller effect sizes than between-subjects design studies. Studies that used k as a discounting rate measure had significantly smaller effect sizes than studies that used area under the discounting curve or other atheoretical discounting measures. The size of the EFT effect was robust across different participant characteristics and ages, suggesting that EFT may be utilized as an effective intervention for a variety of age groups and impulsive behaviors. Experiments 2A, 2B and 2C assessed the suitability of an alternative and briefer delay discounting procedure (in which participants simply report their indifference points) for subsequent EFT experiments. The report indifference points procedure produced a high percentage of invalid data, a finding that was replicated across all three experiments. We therefore continued to use the well-established titrating-amount procedure in subsequent studies. Experiment 3A found that episodic past thinking (imagining personal past events) and semantic future thinking (estimating what a person could buy with the larger, delayed amount) had no effect on discounting, indicating that both episodic thinking and future thinking are necessary components of the EFT effect. Experiment 3A results also indicated that financial relevance alone is not sufficient to reducing discounting. Experiment 3B found that the future events also need to be personally relevant to reduce discounting, and that participants perceived EFT to reduce their discounting by primarily making the larger, delayed reward more valuable. We also showed that demand characteristics, where participants change their behavior to conform to the researcher’s expectations, are an unlikely explanation for the EFT effects found in Experiments 3A and 3B. Further research is warranted to form a better understanding of the mechanism(s) through which EFT reduces delay discounting.</p>

The effect of episodic future thinking on delay discounting

<p>Delay discounting refers to the fact that rewards lose their value if they are delayed. Excessive delay discounting is associated with various health-related problems such as over-eating and substance abuse. One phenomenon shown to reduce delay discounting is Episodic Future Thinking (EFT; imagining personal future events). Across multiple experiments and a meta-analysis, the current thesis examined the reliability of the effect of EFT on delay discounting and also sought to clarify the components of EFT that are necessary to reduce delay discounting. Experiment 1 replicated the EFT effect using a common titrating-amount procedure, and the meta-analysis based on 40 independent studies confirmed that EFT has a reliable, medium-sized effect on delay discounting. The meta-analysis also assessed the robustness of the EFT effect across various methodological features and participant characteristics. A multiple meta-regression revealed that the between-study variability in the size of the EFT effect was accounted for by study design and type of discounting measure. Within-subjects design studies had significantly smaller effect sizes than between-subjects design studies. Studies that used k as a discounting rate measure had significantly smaller effect sizes than studies that used area under the discounting curve or other atheoretical discounting measures. The size of the EFT effect was robust across different participant characteristics and ages, suggesting that EFT may be utilized as an effective intervention for a variety of age groups and impulsive behaviors. Experiments 2A, 2B and 2C assessed the suitability of an alternative and briefer delay discounting procedure (in which participants simply report their indifference points) for subsequent EFT experiments. The report indifference points procedure produced a high percentage of invalid data, a finding that was replicated across all three experiments. We therefore continued to use the well-established titrating-amount procedure in subsequent studies. Experiment 3A found that episodic past thinking (imagining personal past events) and semantic future thinking (estimating what a person could buy with the larger, delayed amount) had no effect on discounting, indicating that both episodic thinking and future thinking are necessary components of the EFT effect. Experiment 3A results also indicated that financial relevance alone is not sufficient to reducing discounting. Experiment 3B found that the future events also need to be personally relevant to reduce discounting, and that participants perceived EFT to reduce their discounting by primarily making the larger, delayed reward more valuable. We also showed that demand characteristics, where participants change their behavior to conform to the researcher’s expectations, are an unlikely explanation for the EFT effects found in Experiments 3A and 3B. Further research is warranted to form a better understanding of the mechanism(s) through which EFT reduces delay discounting.</p>

From Nationalism to National Indifference: Binary Logic and Sense of Time

The vast body of inquiry into nationalism has traditionally seen Europe as a main center for the emergence of nationalism, but scholars of “national indifference” have countered with the idea that nationalism may not matter much at all as a motive for most people. The concept of national indifference calls into question the power of nationalism as a motive for action and the mass appeal of nationalism. Studies of national indifference have constructed an alternative non-national narrative, but face particular challenges accounting for major themes and episodes of discrimination and violence. At its core, national indifference paradoxically both rejects and accepts binary notions of identity and incorporates binary assumptions about motives. It is tempting to resolve the contest between parallel accounts of pervasive, powerful nationalism and national indifference by choosing a victor, but this contrast between models shows the fluidity and dynamism of nationalism. The debate between the now classic accounts of nationalism and the alternative of national indifference points to the importance of often overlooked variables: frames and sense of time.

Benefits of Neuroeconomic Modeling: New Policy Interventions and Predictors of Preference

Neuroeconomics strives to use knowledge from neuroscience to improve models of decisionmaking. Here we introduce a biologically plausible, drift-diffusion model that is able to jointly predict choice behavior and response times across different choice environments. The model has both normative and positive implications for economics. First, we consistently observe that decisionmakers inefficiently allocate their time to choices for which they are close to indifference. We demonstrate that we can improve subjects' welfare using a simple intervention that puts a time limit on their choices. Second, response times can be used to predict indifference points and the strength of preferences.

Using Indifference Points in Engineering Decisions

Multi-criteria decision support methods are common in engineering design. These methods typically rely on the specification of importance weights to accomplish trade-offs among competing objectives. Such methods can have difficulties, however: they may not be able to select all possible Pareto optima, and the direct specification of importance weights can be arbitrary and ad hoc. The inability to reach all Pareto optima is shown to be surmountable by the consideration of trade-off strategy as an additional parameter of a decision. The use of indifference points to select a best solution, as an alternative to direct specification of importance weights, is presented, and a simple truss design example is used to illustrate the concepts.

Correction to “Separation-of-Powers Games in the Positive Theory of Congress and Courts”

In my article, “Separation-of-Power Games in the Positive Theory of Congress and Courts” (Segal 1997) I compared the theoretical and empirical validity of the separation-of-powers model and the judicial attitudinal model as applied to U.S. Supreme Court decision making. I found that the preferences of the justices often fell inside the set of irreversible decisions, and that even when the preferences fell outside the set, the justices, with the exception of Earl Warren, showed little evidence of constraint. I concluded, consistent with the attitudinal model, that the justices overwhelmingly engaged in rationally sincere behavior.Tim Groseclose and Sara Schiavoni (1998), whom I thank for their efforts, have alerted me to two errors in my calculation of the set of irreversible decisions. First, I used the formula 2CC-G (where CC = the conference committee and G = the gatekeeper) for calculating indifference points in the constraint set rather than 2G-CC. Second, I implicitly allowed Congress to pass legislation that would be vetoed and could not be overridden. Correcting this error changes the optimal behavior of the conference committee, which will not propose legislation that can be vetoed but cannot be overriden, and the gatekeepers, who must consider the conference committee's actions.In this note I replicate the study using the corrected data and find first that the sets of irreversible decisions are a bit broader than I had originally found. This means that fewer justices could be constrained by Congress than I had originally concluded.