Steep discounting of delayed monetary and food rewards in obesity: a meta-analysis

Time Cost and Demand: Implications for Public Policy

The success of policy involves not only good design but a good understanding of how the public will respond behaviorally to the benefits or detriments of that policy. Behavioral science has greatly contributed to how we understand the impact of monetary costs on behavior and has therefore contributed to policy design. Consumption taxes are a direct result of this; for example, cigarette taxes that aim to reduce cigarette consumption. In addition to monetary costs, time may also be conceptualized as a constraint on consumption. Time costs may therefore have policy implications, for example, long waiting times could deter people from accessing certain benefits. Recent data show that behavioral economic demand curve methods used to understand monetary cost may also be used to understand time costs. In this article we discuss how the impact of time cost can be conceptualized as a constraint on demand for public benefits utilization and public health when there are delays to receiving the benefits. Policy examples in which time costs may be relevant and demand curve methods may be useful are discussed in the areas of government benefits, public health, and transportation design.

Goal language is associated with attrition and weight loss on a digital program: Observational study

Behavioral weight loss reduces risk of weight-related health complications. Outcomes of behavioral weight loss programs include attrition and weight loss. There is reason to believe that individuals' written language on a weight management program may be associated with outcomes. Exploring associations between written language and these outcomes could potentially inform future efforts towards real-time automated identification of moments or individuals at high risk of suboptimal outcomes. Thus, in the first study of its kind, we explored whether individuals' written language in actual use of a program (i.e., outside of a controlled trial) is associated with attrition and weight loss. We examined two types of language: goal setting (i.e., language used in setting a goal at the start of the program) and goal striving (i.e., language used in conversations with a coach about the process of striving for goals) and whether they are associated with attrition and weight loss on a mobile weight management program. We used the most established automated text analysis program, Linguistic Inquiry Word Count (LIWC), to retrospectively analyze transcripts extracted from the program database. The strongest effects emerged for goal striving language. In striving for goals, psychologically distanced language was associated with more weight loss and less attrition, while psychologically immediate language was associated with less weight loss and higher attrition. Our results highlight the potential importance of distanced and immediate language in understanding outcomes like attrition and weight loss. These results, generated from real-world language, attrition, and weight loss (i.e., from individuals' natural usage of the program), have important implications for how future work can better understand outcomes, especially in real-world settings.

A Neuroeconomics Approach to Obesity

Obesity is a heterogeneous condition that is affected by physiological, behavioral, and environmental factors. Value-based decision making is a useful framework for integrating these factors at the individual level. The disciplines of behavioral economics and reinforcement learning provide tools for identifying specific cognitive and motivational processes that may contribute to the development and maintenance of obesity. Neuroeconomics complements these disciplines by studying the neural mechanisms underlying these processes. We surveyed recent literature on individual decision characteristics that are most frequently implicated in obesity: discounting the value of future outcomes, attitudes toward uncertainty, and learning from rewards and punishments. Our survey highlighted both consistent and inconsistent behavioral findings. These findings underscore the need to examine multiple processes within individuals to identify unique behavioral profiles associated with obesity. Such individual characterization will inform future studies on the neurobiology of obesity as well as the design of effective interventions that are individually tailored.

Reducing impulsive choice: VIII. Effects of delay-exposure training in female rats

Impulsive choice may play an important role in serious health-related decisions, like addiction tendencies. Thus, there is merit in exploring interventions that reduce impulsive choice. Delay-exposure training involves extended experience with delayed reinforcement. Following training, delay-exposed rats make fewer impulsive choices than control rats. The reducing effects of delay exposure training on impulsive choice have been replicated in male rats seven times. For the first time, this study evaluated the effects of delay exposure training in female rats. Thirty-six rats were randomly assigned to either delay-exposure or immediacy-exposure training. Then, rats underwent two impulsive choice assessments in which they chose between one immediate pellet or three delayed pellets. In the first assessment, delays increased within-sessions, across trial blocks from 0, 8, 16, to 32 s. In the second assessment, delays to the larger reward increased between-sessions, from 8, 16, 32, to 4 s. Unlike findings with male rats, delay-exposure training produced a reduction in impulsive choice only in the initial five sessions in female rats. Possible reasons for the lack of lasting effect in female rats are discussed and future research directions are identified.

The physiological control of eating: signals, neurons, and networks

During the past 30 yr, investigating the physiology of eating behaviors has generated a truly vast literature. This is fueled in part by a dramatic increase in obesity and its comorbidities that has coincided with an ever increasing sophistication of genetically based manipulations. These techniques have produced results with a remarkable degree of cell specificity, particularly at the cell signaling level, and have played a lead role in advancing the field. However, putting these findings into a brain-wide context that connects physiological signals and neurons to behavior and somatic physiology requires a thorough consideration of neuronal connections: a field that has also seen an extraordinary technological revolution. Our goal is to present a comprehensive and balanced assessment of how physiological signals associated with energy homeostasis interact at many brain levels to control eating behaviors. A major theme is that these signals engage sets of interacting neural networks throughout the brain that are defined by specific neural connections. We begin by discussing some fundamental concepts, including ones that still engender vigorous debate, that provide the necessary frameworks for understanding how the brain controls meal initiation and termination. These include key word definitions, ATP availability as the pivotal regulated variable in energy homeostasis, neuropeptide signaling, homeostatic and hedonic eating, and meal structure. Within this context, we discuss network models of how key regions in the endbrain (or telencephalon), hypothalamus, hindbrain, medulla, vagus nerve, and spinal cord work together with the gastrointestinal tract to enable the complex motor events that permit animals to eat in diverse situations.

The effect of acute and chronic scarcity on acute stress: A dyadic developmental examination

BACKGROUND

Food insecurity, obesity, and psychological stress are interrelated constructs which are thought to be connected through increased energy intake, but the underlying mechanisms for these relationships remain unclear. The current study used experimental methods to investigate how financial losses may influence acute stress in the context of food insecurity for both parents and offspring. This study also sought to examine the effect of acute stress related to financial losses on the reinforcing value of food (RRV_food) and delay discounting (DD).

METHODS

One hundred and six families stratified by both offspring age (53 children aged 7-10, 53 adolescents aged 15-17) and household financial resources, visited our laboratory for three separate appointments. Each appointment included the experimental manipulation of financial gains and losses, saliva samples for cortisol assay, continuous heart rate monitoring, self-rated tension, and computer-based DD and RRV_food tasks. Participants also completed surveys to report perceived life stress level and food insecurity status.

RESULTS

Among all participants, financial losses were related to decreased heart rates and increased self-rated tension. Among parents reporting food insecurity, acute financial losses resulted in an increase in cortisol levels. Changes in cortisol, heart rate, and tension were not related to RRV_food or DD.

CONCLUSION

Food insecure parents are sensitive to financial losses and respond with an increase in cortisol. However, we found no evidence for a relationship between cortisol and RRV_food or DD. This sensitivity to financial losses did not extend to children or adolescents.

Delay Discounting as a Potential Therapeutic Target for Weight Loss in Breast Cancer Survivors

Obesity in breast cancer (BC) survivors is associated with increased mortality. Delay discounting (DD) is a behavioral economic measure of how individuals value future outcomes. Higher DD correlates with obesity in the general population. Valuation of the future may be associated with obesity differently in cancer survivors. This study evaluated the relationship between DD and obesity in BC survivors. We report an exploratory analysis assessing cross-sectional associations between DD, BMI, and lifestyle behaviors (vegetable and fruit consumption, exercise) related to obesity in 89 women with hormone receptor positive non-metastatic BC. Multivariate linear regression analysis examined demographic and lifestyle behavior variables associated with both BMI and DD. Greater willingness to wait for larger, delayed rewards (lower DD) was significantly associated with lower BMI (standardized beta = −0.32; p < 0.01), independent of age, race, income, time since diagnosis, and menopausal status. There was no significant association between DD and fruit consumption or exercise frequency. Vegetable consumption was significantly associated with lower DD (standardized beta = 0.24; p < 0.05). Higher DD is associated with obesity and decreased frequency of vegetable consumption in BC survivors. Future studies should investigate DD as a therapeutic target for behavioral interventions to facilitate weight loss and promote longevity in this population.

Effects of substance use on monetary delay discounting among people who use stimulants with and without HIV: An ecological momentary assessment study

Exploration of the real-time relationship between substance use and delay discounting may reveal potential mechanisms driving high-risk behaviors. We conducted an ecological momentary assessment (EMA) study to investigate the effects of substance use on delay discounting in a sample of people who use stimulants (HIV+: 30; HIV-: 34). Participants completed multiple EMAs throughout the day for 28 days. The EMAs collected data on delay discounting and substance use (time since last substance use and level of intoxication). Delay discounting was assessed using a brief Monetary Choice Questionnaire (MCQ). Analyses were conducted using linear mixed effects modeling. Most participants (99.1%) used cocaine as their primary stimulant. Among participants without HIV, MCQ score remained relatively stable during the first 2 hr after stimulant use, followed by an increase during 2-6 hr (p < .05), before decreasing again. For alcohol and marijuana, the MCQ score was stable during the first 4 hr after use, with a sharp increase at 4-6 hr (p < .05), before decreasing again. Among participants with HIV, there were no changes in MCQ score as a function of time since recent substance use. These findings provide evidence of a plausible connection between delay discounting and acute withdrawal that may have relevance for risky behaviors. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Effects of 6-month episodic future thinking training on delay discounting, weight loss and HbA1c changes in individuals with prediabetes

People with prediabetes are at risk for type 2 diabetes. They may discount the future delay discounting (DD), and not engage in preventive health behaviors. Episodic future thinking (EFT) can reduce DD when future scenarios are cued, but research is needed to assess long-term effects of EFT and when EFT is not cued. This study tested EFT training compared to control for people with prediabetes enrolled in a 6-month weight loss program on DD, weight, HbA1c, and physical activity. Results showed a reliable EFT effect on reducing DD in cued (p = 0.0035), and uncued DD tasks (p = 0.048), and significant overall changes in weight (p < 0.001), HbA1c (p, 0.001) and physical activity (p = 0.003), but no significant differences in these outcomes by group (p’s > 0.05). Sixty-eight percent of the sample ended below the prediabetes HbA1c range. These results suggest that DD can be modified over extended periods, and the effects of EFT can be observed without EFT cues. However, these data do not suggest that changes in weight, HbA1c or physical activity were due to EFT training. The study was initiated before the COVID-19 pandemic which provided the opportunity to compare differences for people treated in-person or remotely. Analyses showed no differences in DD, weight, HBA1c or physical activity outcomes were observed between in-person and remote treatment, suggesting telehealth is a scalable approach to treating prediabetes.

Age-related effects in delay discounting for food

Developmental influences of growth, such as hormones and metabolic factors, increase food intake and weight across the lifespan. Delay discounting (DD), a choice procedure that characterizes preferences for immediate rewards, such as food, over larger, more delayed ones may be useful in understanding developmental and metabolic changes in decision making processes related to food intake. The present study examined the relation between age and food DD in a cross-sectional design. Other variables, such as pubertal stage, were examined also as these may influence discounting. Participants (N = 114; 28 children and 86 adult) from a community sample completed measures of food and money delay discounting to determine if age-related variation in discounting tendencies is food-specific or more general. Both measures yield an omnibus discounting value and three additional values for small, medium, and large magnitudes. Analyses first revealed magnitude effects-- smaller magnitudes of both food and money were discounted more steeply than larger magnitudes. Hierarchical regressions indicated subjective hunger predicted steeper food discounting. When subjective hunger was controlled, age, but not puberty, significantly predicted food discounting for omnibus, medium, and large magnitudes of food. In children, food discounting decreased from early childhood to late adolescence. In adults, food discounting increased from early to late adulthood. Neither age, puberty, nor obesity status predicted any measure of monetary discounting. Food discounting, then, appears to change across the lifespan, and therefore, may be appropriate to examine psychological processes that accompany developmental and metabolic changes across the lifespan.

Executive function in obesity and anorexia nervosa: Opposite ends of a spectrum of disordered feeding behaviour?

Higher-order executive functions such as decision-making, cognitive flexibility and behavioural control are critical to adaptive success in all aspects of life, including the maintenance of a healthy body weight by regulating food intake. Performance on tasks designed to assess these aspects of cognition is impaired in individuals with obesity and anorexia nervosa (AN); conditions at either end of a spectrum of body weight disturbance. While the conceptualisation of obesity and AN as mirror images of each other makes some sense from a metabolic point of view, whether or not these conditions also reflect opposing states of executive function is less clear. Here, we review evidence from neurocognitive and neuroimaging studies to compare the direction and extent of executive dysfunction in subjects with obesity and AN and how these are underpinned by changes in structure and function of subregions of the prefrontal cortex (PFC). Both conditions of extreme body weight disturbance are associated with impaired decision-making and cognitive inflexibility, however, impulsive behaviour presents in opposing directions; obesity being associated with reduced behavioural control and AN being associated with elevated control over behaviour with respect to food and feeding. Accordingly, the subregions of the PFC that guide inhibitory control and valuation of action outcomes (dorsolateral prefrontal cortex and orbitofrontal cortex) show opposite patterns of activation in subjects with obesity compared to those with AN, whereas the subregions implicated in cognitive and behavioural flexibility (ventromedial prefrontal cortex and anterior cingulate cortex) show alterations in the same direction in both conditions but with differential extent of dysfunction. We synthesise these findings in the context of the utility of animal models of obesity and AN to interrogate the detail of the neurobiological contributions to cognition in patient populations and the utility of such detail to inform future treatment strategies that specifically target executive dysfunction.

Delay Discounting in Established and Proposed Behavioral Addictions: A Systematic Review and Meta-Analysis

Steep delay discounting, or a greater preference for smaller-immediate rewards over larger-delayed rewards, is a common phenomenon across a range of substance use and psychiatric disorders. Non-substance behavioral addictions (e.g., gambling disorder, internet gaming disorder, food addiction) are of increasing interest in delay discounting research. Individual studies have reported steeper discounting in people exhibiting various behavioral addictions compared to controls or significant correlations between discounting and behavioral addiction scales; however, not all studies have found significant effects. To synthesize the published research in this area and identify priorities for future research, we conducted a pre-registered systematic review and meta-analysis (following PRISMA guidelines) of delay discounting studies across a range of behavioral addiction categories. The final sample included 78 studies, yielding 87 effect sizes for the meta-analysis. For studies with categorical designs, we found statistically significant, medium-to-large effect sizes for gambling disorder (Cohen’s d = 0.82) and IGD (d = 0.89), although the IGD effect size was disproportionately influenced by a single study (adjusted d = 0.53 after removal). Categorical internet/smartphone studies were non-significant (d = 0.16, p = 0.06). Aggregate correlations in dimensional studies were statistically significant, but generally small magnitude for gambling (r = 0.22), internet/smartphone (r = 0.13) and food addiction (r = 0.12). Heterogeneity statistics suggested substantial variability across studies, and publication bias indices indicated moderate impact of unpublished or small sample studies. These findings generally suggest that some behavioral addictions are associated with steeper discounting, with the most robust evidence for gambling disorder. Importantly, this review also highlighted several categories with notably smaller effect sizes or categories with too few studies to be included (e.g., compulsive buying, exercise addiction). Further research on delay discounting in behavioral addictions is warranted, particularly for categories with relatively few studies.

The social contagion of temporal discounting in small social networks

Decisions often require a tradeoff between immediate and long-term gratification. How individuals resolve such tradeoffs reflects constructs such as temporal discounting, the degree that individuals devalue delayed rewards. Recent research has started to focus on temporal decisions made in collaborative contexts (e.g., dyads, small groups). Results suggest that directly interacting with others leads to revisions in preferences, such that decision makers become more similar to their collaborative partners over time (e.g., more patient following collaboration with a patient other). What remains to be seen is whether this social influence extends to indirect social effects, such as when an individual influences another’s preferences through a shared collaborative partner. In the current study, the focus was on decisions regarding hypothetical monetary rewards. Groups of three participated in a collaborative decision-making chain, in which network member X collaborated with member Y, who then subsequently collaborated with member Z. Though network members X and Z never directly interacted, a significant indirect link was observed between member X’s pre-collaborative decision preferences and member Z’s post-collaborative decision preferences. These results demonstrate that temporal decision preferences can be transmitted through intervening connections in a small social network (i.e., social contagion), showing that indirect social influence can be empirically observed and measured in controlled environments.

Single- and cross-commodity discounting among adults who use alcohol and cannabis: Associations with tobacco use and clinical indicators

BACKGROUND

Delay discounting assessments typically involve choices between an immediate outcome and a larger amount of the same outcome after a delay. Real-world choices, however, more often involve qualitatively different alternatives. The primary aim of this study was to examine single- and cross-commodity discounting of money, alcohol, and cannabis, along with clinical measures of alcohol and cannabis use among people who use both alcohol and cannabis, yet differ in tobacco cigarette smoking status (i.e., dual- versus tri-use).

METHODS

An online crowdsourced sample (N = 318) of people who reported using alcohol and cannabis in the past week completed single- and cross-commodity discounting assessments across each combination of money, alcohol, and cannabis. We recruited a balanced number of people who did and did not also use tobacco cigarettes and examined associations between discounting, tobacco use, and clinical indicators.

RESULTS

People who reported using tobacco cigarettes in addition to alcohol and cannabis tended to engage in significantly higher rates of harmful alcohol and cannabis use than those who reported using only alcohol and cannabis. Cross-commodity discounting was significantly associated with patterns of harmful alcohol and cannabis use while no associations emerged for single-commodity discounting.

CONCLUSIONS

Cross-commodity discounting provides a nuanced account of intertemporal choice by incorporating relative commodity valuation and appears to characterize harmful alcohol and cannabis use more clearly than single-commodity arrangements. Further cross-commodity research is needed to better understand the interplay between temporal location and relative commodity value among people who use multiple substances.

Choice bundling, unpacked: Observed and predicted effects on intertemporal choice in an additive model of hyperbolic delay discounting

One method known to increase preference for larger, later rewards (LLRs) over smaller, sooner rewards (SSRs) is choice bundling, in which a single choice produces a series of repeating consequences over time. The present study examined whether effects of choice bundling on preference for LLRs: (1) increase with the number of rewards in the bundle (i.e., bundle size); (2) are independent of differences in reward magnitude between conditions; and (3) accord with predictions of an additive model of hyperbolic delay discounting, in which the value of a bundle of rewards can be expressed as the summed discounted value of all rewards in that bundle. Participants (N = 252) completed a choice task to assess valuation of monetary LLRs at bundle sizes of 1 (control), 3, and 9 rewards per choice (ascending/descending order counterbalanced). To control for the magnitude effect, the total reward amounts were held constant across conditions. Choice bundling significantly increased LLR preference (p < .001), with the largest effect observed at the largest bundle size. The descending bundle-size order produced significantly greater LLR preference than the ascending order (p < .05), although order did not significantly interact with bundle size. Difference scores between observed measures and those predicted by an additive model of hyperbolic discounting were small and not significantly different than zero, but were not equivalent to zero. Future research should investigate the clinical utility of choice bundling for reducing the maladaptive health behavior (e.g., substance use) with which delay discounting is associated.

Impulsivity and neural mechanisms that mediate preference for immediate food rewards in people with vs without excess weight

People with excess weight (overweight or obese; body mass index [BMI]>25) are generally characterized as impulsive with regards to food. However, the underlying brain mechanisms of this impulsivity are not fully understood. As such, this study aims at understanding the neural mechanisms underlying impulsivity toward food rewards, as well as differences in delay discounting patterns for hypothetical food between people with vs without excess weight. To this end, participants (79 college students, 33 with excess weight and 46 without) performed a food delay discounting task and completed questionnaires related to food addiction and impulsivity. In the task, we manipulated the magnitude of immediate and delayed rewards and employed event-related fMRI design to measure brain activity. The results showed that people with excess weight, compared to those without, were more impulsive and presented a lower probability of choosing delayed rewards. The higher the BMI was, the lower the probability of choosing delayed rewards was. People with excess weight also had higher impulsivity scores than people with no excess weight. Moreover, people with excess weight had less activation in executive function areas such as the anterior cingulate gyrus, the frontal pole, and the inferior frontal gyrus in both difficult and easy decision-making conditions. These results suggest that hypo-activation of executive function areas may contribute to the progression of decision impulsivity in relation to food, which in turn is associated with excess weight.

Effects of immediate-reinforcement training on delay discounting behavior in rats

Chronic exposure to delayed reinforcement has been shown to increase choice for larger, later reinforcement in a subsequent delay discounting task. In the 3 experiments presented in this paper, the opposite was tested: effects of chronic exposure to immediate reinforcement on choice in a subsequent delay discounting task. In Experiment 1, larger, later reinforcement choice was significantly reduced as a result of exposure to immediate reinforcement, compared to a maturation/handle control group, in experienced, male Lewis rats. In Experiment 2, with naive male and female Wistar rats, and Experiment 3, with naïve male Long Evans rats, the impact of exposure to immediate reinforcement was less robust, but directionally consistent with results from Experiment 1. These results align with some previous work reporting that exposure to immediate reinforcement may decrease choice for larger, later reinforcement in a delay discounting task, and/or blunt maturational increases in choice for larger, later reinforcement. These findings have implications for future research investigating experience-based interventions to manipulate delay discounting behavior. They also have clinical implications for understanding and treating disorders involving maladaptive choice.

Functional Abnormality of the Executive Control Network in Individuals With Obesity During Delay Discounting

Individuals with obesity (OB) prefer immediate rewards of food intake over the delayed reward of healthy well-being achieved through diet management and physical activity, compared with normal-weight controls (NW). This may reflect heightened impulsivity, an important factor contributing to the development and maintenance of obesity. However, the neural mechanisms underlying the greater impulsivity in OB remain unclear. Therefore, the current study employed functional magnetic resonance imaging with a delay discounting (DD) task to examine the association between impulsive choice and altered neural mechanisms in OB. During decision-making in the DD task, OB compared with NW had greater activation in the dorsolateral prefrontal cortex (DLPFC) and posterior parietal cortex, which was associated with greater discounting rate and weaker cognitive control as measured with the Three-Factor Eating Questionnaire (TFEQ). In addition, the association between DLPFC activation and cognitive control (TFEQ) was mediated by discounting rate. Psychophysiological interaction analysis showed decreased connectivity of DLPFC-inferior parietal cortex (within executive control network [ECN]) and angular gyrus-caudate (ECN-reward) in OB relative to NW. These findings reveal that the aberrant function and connectivity in core regions of ECN and striatal brain reward regions underpin the greater impulsivity in OB and contribute to abnormal eating behaviors.

The relationship between dietary fat intake, impulsive choice, and metabolic health

Unhealthful foods are convenient, ubiquitous, and inexpensive. Overconsumption of unhealthful foods can result in disease states such as obesity and Type 2 diabetes. In addition to the physiological consequences of unhealthful foods, research in rats has shown that diets high in processed fat and sugar induce impulsive choice behavior. Research in humans has demonstrated a link between metabolic health and impulsive choice, but most investigations have not included diet. We investigated how dietary fat intake interacts with body fat percentage, fasting glucose, insulin response, and systemic inflammation levels to predict impulsive choices in humans. Participants were split into either Control (<35% calories from fat) or High-Fat (≥40% calories from fat) groups based on self-reported dietary intake, completed an impulsive choice task, and underwent testing to determine their body fat, glucose, insulin response, and inflammation levels. High-fat diets were not predictive of impulsive choices, but added sugar was predictive. Body fat percentage was associated with impulsive choices only in the group who reported consuming high-fat diets. In addition, fasting glucose was associated with impulsive choices in the control group. Therefore, metabolic health and dietary fat intake interacted to predict impulsive choices. These findings indicate that knowledge of dietary patterns coupled with metabolic health markers may help us better understand impulsive choices, thereby improving our ability to target individuals who could benefit from interventions to reduce impulsive choice behavior, with the goal of promoting more self-controlled food choices.

A review of effort-based decision-making in eating and weight disorders

Effort-based decision-making provides a framework to understand the mental computations estimating the amount of work ("effort") required to obtain a reward. The aim of the current review is to systematically synthesize the available literature on effort-based decision-making across the spectrum of eating and weight disorders. More specifically, the current review summarises the literature examining whether 1) individuals with eating disorders and overweight/obesity are willing to expend more effort for rewards compared to healthy controls, 2) if particular components of effort-based decision-making (i.e. risk, discounting) relate to specific binge eating conditions, and 3) how individual differences in effort and reward -processing measures relate to eating pathology and treatment measures. A total of 96 studies were included in our review, following PRISMA guidelines. The review suggests that individuals with binge eating behaviours 1) are more likely to expend greater effort for food rewards, but not monetary rewards, 2) demonstrate greater decision-making impairments under risk and uncertainty, 3) prefer sooner rather than delayed rewards for both food and money, and 4) demonstrate increased implicit 'wanting' for high fat sweet foods. Finally, individual differences in effort and reward -processing measures relating to eating pathology and treatment measures are also discussed.

Delayed Reward Discounting as a Prognostic Factor for Smoking Cessation Treatment Outcome: A Systematic Review

INTRODUCTION

While large proportions of smokers attempt to quit, rates of relapse remain high and identification of valid prognostic markers is of high priority. Delayed reward discounting (DRD) is a behavioral economic index of impulsivity that has been associated with smoking cessation, albeit inconsistently. This systematic review sought to synthesize the empirical findings on DRD as a predictor of smoking cessation treatment outcome, to critically appraise the quality of the literature, and to propose directions for future research.

AIMS AND METHODS

A total of 734 articles were identified, yielding k = 14 studies that met the eligibility criteria. The Quality in Prognosis Studies (QUIPS) tool was used to assess methodological quality of the included studies.

RESULTS

Individual study methods were highly heterogeneous, including substantial variation in research design, DRD task, clinical subpopulation, and treatment format. The predominant finding was that steeper DRD (higher impulsivity) was associated with significantly worse smoking cessation outcomes (10/14 studies). Negative results tended to be in pregnant and adolescent subpopulations. The QUIPS results suggested low risk of bias across studies; 11/14 studies were rated as low risk of bias for 5/6 QUIPS domains.

CONCLUSIONS

This review revealed consistent low-bias evidence for impulsive DRD as a negative prognostic predictor of smoking cessation treatment outcome in adults. However, methodological heterogeneity was high, precluding meta-analysis and formal tests of small study bias. The prospects of targeting impulsive DRD as a potentially modifiable risk factor or providing targeted treatment for smokers exhibiting high levels of discounting are discussed.

IMPLICATIONS

These findings indicate consistent evidence for DRD as a negative prognostic factor for smoking cessation outcome in adults. As such, DRD may be a useful as a novel treatment target or for identifying high-risk populations requiring more intensive treatment.

Dysregulated resting state functional connectivity and obesity: A systematic review

Obesity has been variously linked to differences in brain functional connectivity in regions associated with reward, emotional regulation and cognition, potentially revealing neural mechanisms contributing to its development and maintenance. This systematic review summarizes and critically appraises the existing literature on differences in resting state functional connectivity (Rs-FC) between overweight and individuals with obesity in relation healthy-BMI controls. Twenty-nine studies were identified and the results consistently support the hypothesis that obesity is associated with differences in Rs-FC. Specifically, obesity/overweight was consistently associated with (i) DMN hypoconnectivity and salience network hyperconnectivity; (ii) increased Rs-FC between the hypothalamus and reward, limbic and salience networks, and decreased Rs-FC between the hypothalamus and cognitive regions; (iii) increased power within regions associated with inhibition/emotional reasoning; (iv) decreased nodal efficiency, degree centrality, and global efficiency. Collectively, the results suggest obesity is associated with disrupted connectivity of brain networks responsible for cognition, reward, self-referential processing and emotional regulation.

Temporal discounting as a candidate behavioral marker of obesity

Although obesity is a result of processes operating at multiple levels, most forms result from decision-making behavior. The aim of this review was to examine the candidacy of temporal discounting (TD) (i.e. the reduction in the value of a reinforcer as a function of the delay to its receipt) as a behavioral marker of obesity. For this purpose, we assessed whether TD has the ability to: identify risk for obesity development, diagnose obesity, track obesity progression, predict treatment prognosis/outcomes, and measure treatment effectiveness. Three databases (Pubmed, PsycINFO, and Web of Science) were searched using a combination of terms related to TD and obesity. A total of 153 papers were reviewed. Several areas show strong evidence of TD's predictive utility as a behavioral marker of obesity (e.g., distinguishing obese from non obese). However, other areas have limited and/or mixed evidence (e.g., predicting weight change). Given the positive relationship for TD in the majority of domains examined, further consideration for TD as a behavioral marker of obesity is warranted.

Delay discounting in youth at clinical high-risk for psychosis and adults with schizophrenia

BACKGROUND

Schizophrenia (SZ) is typically preceded by a prodromal (i.e. pre-illness) period characterized by attenuated positive symptoms and declining functional outcome. Negative symptoms are prominent among individuals at clinical high-risk (CHR) for psychosis (i.e. those with prodromal syndromes) and highly predictive of conversion to illness. Mechanisms underlying negative symptoms in the CHR population are unclear. Two studies were conducted to evaluate whether abnormalities in a reward processing mechanism thought to be core to negative symptoms in SZ, value representation, also exist in CHR individuals and whether they are associated with negative symptoms transphasically.

METHODS

Study 1 included 33 individuals in the chronic phase of illness who have been diagnosed with schizophrenia or schizoaffective disorder (SZ) and 40 healthy controls (CN). Study 2 included 37 CHR participants and 45 CN. In both studies, participants completed the delay discounting (DD) task as a measure of value representation and the Brief Negative Symptom Scale was rated to measure negative symptoms.

RESULTS

Results indicated that patients with SZ had steeper discounting rates than CN, indicating impairments in value representation. However, CHR participants were unimpaired on the DD task. In both studies, steeper discounting was associated with greater severity of negative symptoms.

CONCLUSIONS

These findings suggest that deficits in value representation are associated with negative symptoms transphasically.

Delay discounting, cognitive ability, and personality: What matters?

Steep delay discounting is associated with problems such as addiction, obesity, and risky sexual behavior that are frequently described as reflecting impulsiveness and lack of self-control, but it may simply indicate poor cognitive functioning. The present investigation took advantage of the unique opportunity provided by the Human Connectome Project (N=1,206) to examine the relation between delay discounting and 11 cognitive tasks as well as the Big Five fundamental personality traits. With income level and education statistically controlled, discounting was correlated with only four of the 11 cognitive abilities evaluated, although the rs were all small (<.20). Importantly, the two discounting measures loaded on their own factor. Discounting was not correlated with Neuroticism or Conscientiousness, traits related to psychometric impulsiveness and self-control. These findings suggest that steep delay discounting is not simply an indicator of poor cognitive functioning or psychometric impulsiveness but an important individual difference characteristic in its own right.

Meta-analyses and effect sizes in applied behavior analysis: A review and discussion

For more than four decades, researchers have used meta-analyses to synthesize data from multiple experimental studies often to draw conclusions that are not supported by individual studies. More recently, single-case experimental design (SCED) researchers have adopted meta-analysis techniques to answer research questions with data gleaned from SCED experiments. Meta-analyses enable researchers to answer questions regarding intervention efficacy, generality, and condition boundaries. Here we discuss meta-analysis techniques, the rationale for their adaptation with SCED studies, and current indices used to quantify the effect of SCED data in applied behavior analysis.

Daily, but not occasional, cannabis use is selectively associated with more impulsive delay discounting and hyperactive ADHD symptoms in binge-drinking young adults

RATIONALE

There is increasing interest in and evidence for the negative impacts of cannabis use in cognitive performance and symptoms of attention-deficit/hyperactivity disorder (ADHD), with age of first cannabis use as a potential amplifier of these associations. However, the existing literature is inconsistent, which may be due to methodological limitations, including small sample sizes.

OBJECTIVE

To examine current cannabis use and age of first cannabis use in relation to neurocognitive task performance and ADHD symptoms in a large sample of binge-drinking young adults.

METHODS

Participants were young adults (N=730, M age=21.44, 52.6% female) assessed for current cannabis use, neurocognitive task performance, and ADHD symptoms. Three-group ANCOVAs compared individuals reporting frequent (daily/multiple times daily), occasional (weekly/monthly), or no cannabis use.

RESULTS

Covarying alcohol use, tobacco use, age, sex, income, and education, daily cannabis users exhibited significantly more impulsive delay discounting and hyperactive-impulsive ADHD symptoms compared to both other groups. However, cannabis use was not associated with inattentive ADHD symptoms, verbal intelligence, working memory, probability discounting, short-term verbal memory, or behavioral inhibition. Age of initiation of cannabis use exhibited neither main effects nor interactions in relation to any domains of cognitive performance or ADHD symptomatology.

CONCLUSIONS

The current findings provide support for a link between cannabis use in relation to immediate reward preference and symptoms of hyperactive-impulsive ADHD in young adults, but only among frequent users. No other neurocognitive domains exhibited associations with cannabis and age of first use was neither independently nor interactively associated with cognitive outcomes.

A story to tell: the role of narratives in reducing delay discounting for people who strongly discount the future

Delay Discounting (DD) or devaluing a future, larger reward in favour of a smaller, more immediate reward, has been linked to negative health behaviours. One intervention that reduces DD is Episodic Future Thinking (EFT). EFT has participants generate cues representing positive future events that correspond to temporal windows during the DD task. The current study examined if incorporating EFT cues into narratives would strengthen effects on DD. One hundred and sixty adults were recruited from Amazon Mechanical Turk and were randomised to traditional or narrative EFT. Results showed that participants in narrative EFT discounted the future less (p = 0.034) than participants who engaged in traditional EFT. This novel approach to EFT is well grounded in research and theory on the power of narratives to influence behaviour and can open a new window into ways to reduce DD to strengthen engagement in positive choices.

Transdiagnostic neuroimaging of reward system phenotypes in ADHD and comorbid disorders

ADHD is a disorder characterized by changes in the reward system and which is highly comorbid with other mental disorders, suggesting common neurobiological pathways. Transdiagnostic neuroimaging findings could help to understand whether a dysregulated reward pathway might be the actual link between ADHD and its comorbidities. We here synthesize ADHD neuroimaging findings on the reward system with findings in obesity, depression, and substance use disorder including their comorbid appearance regarding neuroanatomical features (structural MRI) and activation patterns (resting-state and functional MRI). We focus on findings from monetary-incentive-delay (MID) and delay-discounting (DD) tasks and then review data on striatal connectivity and volumetry. Next, for better understanding of comorbidity in adult ADHD, we discuss these neuroimaging features in ADHD, obesity, depression and substance use disorder and ask whether ADHD heterogeneity and comorbidity are reflected by a common dysregulation in the reward system. Finally, we highlight conceptual issues related to heterogeneous paradigms, different phenotyping, longitudinal prediction and highlight some promising future directions for using striatal reward functioning as a clinical biomarker.

The progression of disorder-specific brain pattern expression in schizophrenia over 9 years

Age plays a crucial role in the performance of schizophrenia vs. controls (SZ-HC) neuroimaging-based machine learning (ML) models as the accuracy of identifying first-episode psychosis from controls is poor compared to chronic patients. Resolving whether this finding reflects longitudinal progression in a disorder-specific brain pattern or a systematic but non-disorder-specific deviation from a normal brain aging (BA) trajectory in schizophrenia would help the clinical translation of diagnostic ML models. We trained two ML models on structural MRI data: an SZ-HC model based on 70 schizophrenia patients and 74 controls and a BA model (based on 561 healthy individuals, age range = 66 years). We then investigated the two models’ predictions in the naturalistic longitudinal Northern Finland Birth Cohort 1966 (NFBC1966) following 29 schizophrenia and 61 controls for nine years. The SZ-HC model’s schizophrenia-specificity was further assessed by utilizing independent validation (62 schizophrenia, 95 controls) and depression samples (203 depression, 203 controls). We found better performance at the NFBC1966 follow-up (sensitivity = 75.9%, specificity = 83.6%) compared to the baseline (sensitivity = 58.6%, specificity = 86.9%). This finding resulted from progression in disorder-specific pattern expression in schizophrenia and was not explained by concomitant acceleration of brain aging. The disorder-specific pattern’s progression reflected longitudinal changes in cognition, outcomes, and local brain changes, while BA captured treatment-related and global brain alterations. The SZ-HC model was also generalizable to independent schizophrenia validation samples but classified depression as control subjects. Our research underlines the importance of taking account of longitudinal progression in a disorder-specific pattern in schizophrenia when developing ML classifiers for different age groups.

Temporal discounting when outcomes are experienced in the moment: Validation of a novel paradigm and comparison with a classic hypothetical intertemporal choice task

When faced with intertemporal choices, people typically devalue rewards available in the future compared to rewards more immediately available, a phenomenon known as temporal discounting. Decisions involving intertemporal choices arise daily, with critical impact on health and financial wellbeing. Although many such decisions are "experiential" in that they involve delays and rewards that are experienced in real-time and can inform subsequent choices, most studies have focused on intertemporal choices with hypothetical outcomes (or outcomes delivered after all decisions are made). The present study focused on experiential intertemporal choices. First, a novel intertemporal choice task was developed and validated, using delays experienced in real time and artistic photographs as consumable perceptual rewards. Second, performance on the experiential task was compared to performance on a classic intertemporal choice task with hypothetical outcomes. Involvement of distinct processes across tasks was probed by examining differential relations to state and trait anxiety. A two-parameter logistic function framework was proposed to fit indifference point data. This approach accounts for individual variability not only in the delay at which an individual switches from choosing the delayed to more immediate option, but also in the slope of that switch. Fit results indicated that the experiential task elicited temporal discounting, with effective trade-off between delay and perceptual reward. Comparison with the hypothetical intertemporal choice task suggested distinct mechanisms: first, temporal discounting across the two tasks was not correlated; and second, state and trait anxiety both were associated with choice behavior in the experiential task, albeit in distinct ways, whereas neither was significantly associated with choice behavior in the hypothetical task. The engagement of different processes in the experiential compared to hypothetical task may align with neural evidence for the recruitment of the hippocampus in animal but not in classic human intertemporal choice studies.

Assessing Impulsivity in Humans and Rodents: Taking the Translational Road

Impulsivity is a multidimensional construct encompassing domains of behavioral inhibition as well as of decision making. It is often adaptive and associated with fast responses, being in that sense physiological. However, abnormal manifestations of impulsive behavior can be observed in contexts of drug abuse and attention-deficit/hyperactivity disorder (ADHD), among others. A number of tools have therefore been devised to assess the different facets of impulsivity in both normal and pathological contexts. In this narrative review, we systematize behavioral and self-reported measures of impulsivity and critically discuss their constructs and limitations, establishing a parallel between assessments in humans and rodents. The first rely on paradigms that are typically designed to assess a specific dimension of impulsivity, within either impulsive action (inability to suppress a prepotent action) or impulsive choice, which implies a decision that weighs the costs and benefits of the options. On the other hand, self-reported measures are performed through questionnaires, allowing assessment of impulsivity dimensions that would be difficult to mimic in an experimental setting (e.g., positive/negative urgency and lack of premeditation) and which are therefore difficult (if not impossible) to measure in rodents.

Delay discounting and obesity in food insecure and food secure women

OBJECTIVES

The relation between food insecurity (FI) and delay discounting (DD) and probability discounting (PD) for food and money was tested in women. In addition, discounting was tested as a variable that mediates the relation between obesity and FI.

METHOD

Women recruited from a community sample (N = 92) completed questionnaires. They completed the food choice questionnaire, the monetary choice questionnaire, measures for food and money probability discounting (which quantify sensitivity to risk aversion), and demographic measures.

RESULTS

Women with FI had higher rates of obesity and higher food DD compared to food-secure women. However, DD for money or probability discounting for food or money did not significantly differ between FI and food secure groups when controlling for significant covariates. Neither DD or PD significantly mediated the relation between FI and obesity.

CONCLUSIONS

These results suggest that FI is associated with greater impulsive food choice, but its association with other monetary discounting and probability discounting for food and money appears contingent upon other demographic factors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Effects of a psychosocial intervention at one-year follow-up in a PREDIMED-plus sample with obesity and metabolic syndrome

This study examines if overweight/obesity are related to higher impulsivity, food addiction and depressive symptoms, and if these variables could be modified after 1 year of a multimodal intervention (diet, physical activity, psychosocial support). 342 adults (55-75 years) with overweight/obesity and metabolic syndrome (MetS) from the PREDIMED-Plus Cognition study were randomized to the intervention or to the control group (lifestyle recommendations). Cognitive and psychopathological assessments were performed at baseline and after 1-year follow-up. At baseline, higher impulsivity was linked to higher food addiction and depressive symptoms, but not to body mass index (BMI). Food addiction not only predicted higher BMI and depressive symptoms, but also achieved a mediational role between impulsivity and BMI/depressive symptoms. After 1 year, patients in both groups reported significant decreases in BMI, food addiction and impulsivity. BMI reduction and impulsivity improvements were higher in the intervention group. Higher BMI decrease was achieved in individuals with lower impulsivity. Higher scores in food addiction were also related to greater post-treatment impulsivity. To conclude, overweight/obesity are related to higher impulsivity, food addiction and depressive symptoms in mid/old age individuals with MetS. Our results also highlight the modifiable nature of the studied variables and the interest of promoting multimodal interventions within this population.

The neural correlates of delay discounting in obesity and binge eating disorder

BACKGROUND AND AIMS

Increased delay discounting is associated with obesity and binge eating disorder (BED). Although BED and obesity frequently co-occur, the neural mechanisms underlying delay discounting in these conditions remain poorly understood.

METHODS

Thirtyfive women with obesity, including 10 participants with obesity and BED and 31 controls completed a monetary delay discounting task during functional magnetic resonance imaging.

RESULTS

We identified that increased discounting rates were associated with decreased activity in the left anterior insula in participants with obesity compared to controls when choosing immediate rewards over delayed rewards (PFWE < 0.05). An exploratory analysis comparing the BED subsample to the other groups did not detect significant differences.

DISCUSSION AND CONCLUSIONS

Our findings suggest decreased activity in the anterior insula may underlie heightened delay discounting in individuals with obesity, contributing the probability of choosing immediate rewards over delayed rewards based on emotional states. Future studies including larger, more diverse samples are required to confirm these effects.

Vicarious Trial-and-Error Is Enhanced During Deliberation in Human Virtual Navigation in a Translational Foraging Task

Foraging tasks provide valuable insights into decision-making as animals decide how to allocate limited resources (such as time). In rodents, vicarious trial-and-error (back and forth movements), or VTE, is an important behavioral measure of deliberation which is enhanced early in learning and when animals are presented with difficult decisions. Using new translational versions of a rodent foraging task (the "Movie Row" and "Candy Row"), humans navigated a virtual maze presented on standard computers to obtain rewards (either short videos or candy) offered after a variable delay. Decision latencies were longer when participants were presented with difficult offers, overrode their preferences, and when they accepted an offer after rejecting a previous offer. In these situations, humans showed VTE-like behavior, where they were more likely to pause and/or reorient one or more times before making a decision. Behavior on these tasks replicated previous results from the rodent foraging task ("Restaurant Row") and a human version lacking a navigation component ("Web-Surf") and revealed some species differences. Compared to survey measures of delay-discounting, willingness to wait for rewards in the foraging task was not related to willingness to wait for hypothetical rewards. And, smoking status (use of cigarettes or e-cigarettes) was associated with stronger discounting of hypothetical future rewards, but was not well-related to performance on the foraging tasks. In contrast, individuals with overweight or obese BMI (≥25) did not show stronger delay-discounting, but individuals with BMI ≥ 25, and especially females, showed reduced sensitivity to sunk-costs (where their decisions were less sensitive to irrecoverable investments of effort) and less deliberation when presented with difficult offers. These data indicate that VTE is a behavioral index of deliberation in humans, and further support the Movie and Candy Row as translational tools to study decision-making in humans with the potential to provide novel insights about decision-making that are relevant to public health.

Randomized controlled trials of self-monitoring interventions with or without incentives for diet and exercise among individuals with overweight or obesity: Psychological and behavioural effects

OBJECTIVES

To test the effects of three behavioural interventions (daily monetary incentives + self-monitoring, delayed lump sum monetary incentives + self-monitoring, and self-monitoring only) on psychological constructs and fruit and vegetable consumption or physical activity behaviour change among a sample of adults with overweight or obesity.

DESIGN

A pair of 3-arm longitudinal randomized controlled trials compared daily monetary incentives + self-monitoring, delayed lump sum monetary incentives + self-monitoring, and self-monitoring only interventions for either fruit and vegetable consumption or physical activity.

METHODS

Individuals reporting elevated weight status and insufficient engagement in one of the target behaviours were randomly assigned to one of three 3-week interventions. All three interventions involved daily self-monitoring of the behaviour, and two provided monetary incentives contingent upon reported behaviour. Participants completed measures of psychological constructs and reported behaviour at baseline, the end of the intervention, and two and four weeks post-intervention.

RESULTS

Participants across all three intervention conditions demonstrated increased engagement in the target behaviour from pre- to post-intervention and reported behaviour remained above baseline levels at both follow-up time points. Increases in reported behaviour during the intervention were associated with increases in self-efficacy, and this enhanced self-efficacy prospectively predicted sustained reported behaviour at follow-up. However, contrary to hypotheses, the incentive interventions including self-monitoring were not more efficacious than self-monitoring alone, and increased reported behaviour was not associated with enhancements in attitudes.

CONCLUSIONS

Self-monitoring interventions can aid behaviour change efforts, and behavioural practice during these interventions can increase self-efficacy. However, among adults with overweight or obesity who are seeking behaviour change interventions, incentive-based self-monitoring approaches may not be superior to self-monitoring alone in driving behaviour change and maintenance.

The relationship between delay discounting and Internet addiction: A systematic review and meta-analysis

AIMS

To estimate the difference in delay discounting (DD) between subjects with Internet addiction (IA) and those without as well as to identify significant variables involved in DD.

METHODS

Using the keywords related to IA (e.g., "excessive Internet use", "Internet dependence") AND "delayed reward discounting" OR "delay discounting" OR "temporal discounting" OR "delayed gratification" OR time discounting OR intertemporal choice OR impulsive choice, the PubMed, Embase, and PsycINFO databases were searched from inception to June 2020 for English articles with comparison between subjects with IA and those without. Effect sizes were calculated by group means from the k value or area under the curve (AUC). The random-effects models were used.

RESULTS

Fourteen studies in total were eligible for the current meta-analysis that involved 696 subjects with IA (mean age = 22.71) and 2,394 subjects without (mean age = 21.91). Subjects with IA had a steeper DD rate (g = 1.10, 95% CI: 0.57-1.64; p ≤ 0.01) compared with that in those without. Regarding DD data, the difference between k value and AUC was significant (p < 0.01; AUC > k). Additionally, the estimation of DD by the paper-and-pencil task was larger than that by the computerized task (p < 0.01). Significant difference in the DD rate was also noted between subjects with Internet gaming disorder (IGD) and those with unspecified IA (p = 0.00; IGD > IA). The percentage of men and task variables were significantly associated with the DD rate (all p < 0.01), suggesting impaired DD in subjects with IA.

CONCLUSIONS

Our results suggested the feasibility of utilizing the DD rate as a therapeutic index for cognitive control in IA. Nevertheless, judicious use is recommended taking into consideration the significant difference between k value and AUC.

Anhedonia, positive affect dysregulation, and risk and maintenance of binge-eating disorder

Low positive affect has been identified as an antecedent of binge-eating episodes among individuals with binge-eating disorder (BED), yet positive affect has received far less attention in eating disorders research than its counterpart, negative affect. In this article, we argue that the low levels of positive affect which occur with anhedonia (i.e., loss of interest or pleasure in activities) may contribute to the onset and maintenance of BED. We introduce a theoretical model in which anhedonia increases the risk for BED through its interrelationships with dysregulated eating and weight gain, and we describe potential direct (e.g., reward-related processes) as well as indirect (e.g., influences on depressive symptoms and physical activity) pathways by which anhedonia may lead to adverse eating- and weight-related outcomes. We also propose a momentary maintenance model in which low positive affect and positive affect dysregulation occurring with anhedonia maintain binge eating directly and indirectly through maladaptive health behaviors, such as decreased physical activity, less healthy eating, and fewer social interactions, which in turn maintain anhedonia. We draw upon outside literature to present evidence that aligns with the proposed risk and maintenance models and conclude by outlining avenues for future research-including methodological/measurement, theoretical, and clinical research directions.

Having less and wanting more: an investigation of socioeconomic status and reinforcement pathology

BACKGROUND

In the United states obesity and socioeconomic status (SES), or one's standing in society based on income, education, and/or occupation, are strongly associated. The mechanisms for this relationship may include having high levels of motivation to get food (reinforcing value of food; RRV) and low levels of inhibitory control (delay discounting; DD) which, when combined, is referred to as reinforcement pathology (RP). We sought to examine the relationships among multiple measures of household SES, RP, and age-adjusted body mass index (zBMI) among adolescents.

METHODS

These data were collected as part of ongoing longitudinal study of risk factors for obesity in 244 adolescents. The adolescents and one parent/guardian had height and weight measured and completed surveys. The adolescents completed an adjusting amount DD task and a computer-based RRV task. Analyses consisted of correlations among measures of SES and RRV, DD, and BMI z-scores. In the case of significant associations, multiple regression models were created with theoretically informed covariates.

RESULTS

Household income, parent/guardian education, parent/guardian occupation, and food insecurity status were all related to one another. Among the adolescents, a significant portion of the variance in RRV was accounted for by household income after controlling for covariates. For DD, it was parent/guardian education that was most associated after controlling for covariates.

CONCLUSION

When low income and low parent/guardian education occur together, there may be an increased risk of RP. Separately, food insecurity was predictive of higher parent/guardian BMI. Future research should continue to explore the effects of low income and parent/guardian education on RP among youth by examining them over time.

Exercise Shifts Hypothetical Food Choices toward Greater Amounts and More Immediate Consumption

Although exercise modulates appetite regulation and food intake, it remains poorly understood how exercise impacts decision-making about food. The purpose of the present study was to assess the impact of an acute exercise bout on hypothetical choices related to the amount and timing of food intake. Forty-one healthy participants (22.0 ± 2.6 years; 23.7 ± 2.5 kg/m², 56% female) completed 45 min of aerobic exercise and a resting control condition in randomized order. Food amount preferences and intertemporal food preferences (preference for immediate vs. delayed consumption) were assessed using electronic questionnaires with visual food cues. Compared to rest, exercise resulted in a greater increase in the food amount selected, both immediately post-exercise (+25.8 ± 11.0 vs. +7.8 ± 11.0 kcal/item, p = 0.02) and 30 min post-exercise (+47.3 ± 12.4 vs. +21.3 ± 12.4 kcal/item, p = 0.005). Exercise further resulted in a greater increase in the preference for immediate consumption immediately post-exercise (+0.23 ± 0.10 vs. +0.06 ± 0.10; p = 0.03) and 30 min post-exercise (+0.30 ± 0.12 vs. +0.08 ± 0.12; p = 0.01). Our findings demonstrate that a single bout of aerobic exercise shifts hypothetical food choices toward greater amounts and more immediate consumption, highlighting the importance of the timing of food choices made in the exercise context.

Delay Discounting, Glycemic Regulation and Health Behaviors in Adults with Prediabetes

The majority of people with prediabetes transition to type 2 diabetes. Research has suggested that persons with type 2 diabetes are likely to discount the future and focus on immediate rewards. This study was designed to assess whether this process of delay discounting (DD) is associated with glycemic regulation, medication adherence and eating and exercise behaviors in adults with prediabetes. Participants included 81 adults with prediabetes who were also prescribed hypertension or dyslipidemia drugs, which is common for people with prediabetes. Participants completed adjusting amount DD $100 and $1000 tasks, as well assessments of glycemic control (Hemoglobin (Hb) A1c), medication adherence, diet quality, and objectively measured physical activity. Relationships between DD and these variables were assessed. Results showed higher rates of DD were related to higher HbA1c; as well as poorer medication adherence, lower diet quality and lower physical activity. Hierarchical regression showed that the association between minority status, a known risk factor for type 2 diabetes, was moderated by DD, as minorities with higher DD had greater HbA1c values. Delay discounting may represent a novel target to prevent progression from prediabetes to type 2 diabetes.

Steep Discounting of Future Rewards as an Impulsivity Phenotype: A Concise Review

This chapter provides an overview over the behavioral economic index of impulsivity known as delay discounting. Specifically, delay discounting refers to an individual's preference for smaller immediate rewards over a larger delayed rewards. The more precipitously an individual discounts future rewards, the more impulsive they are considered to be. First, the chapter reviews the nature of delay discounting as a psychological process and juxtaposes it with nominally similar processes, including other facets of impulsivity. Second, the chapter reviews the links between delay discounting and numerous health behaviors, including addiction, attention deficit/hyperactivity disorder, and obesity. Third, the determinants of individual variation in delay discounting are discussed, including both genetic and environmental contributions. Finally, the chapter evaluates delay discounting as a potentially modifiable risk factor and the status of clinical interventions designed to reduce delay discounting to address deficits in self-control in a variety of maladaptive behaviors.

The psychology of obesity: An umbrella review and evidence-based map of the psychological correlates of heavier body weight

Psychological factors may explain why some people develop obesity and others remain a normal weight during their life course. We use an umbrella review approach to build an evidence-based map of the psychological correlates of heavier body weight. Synthesising findings from 42 meta-analyses that have examined associations between psychological factors and heavier body weight, we assessed level of evidence for a range of cognitive, psychosocial and mental health individual difference factors. There is convincing evidence that impaired mental health is associated with heavier body weight and highly suggestive evidence that numerous cognitive factors are associated with heavier body weight. However, the relatively low methodological quality of meta-analyses resulted in lower evidential certainty for most psychosocial factors. Psychological correlates of heavier body weight tended to be small in statistical size and on average, people with obesity were likely to be more psychologically similar than different to people with normal weight. We consider implications for understanding the development of heavier body weight and identifying effective public health interventions to reduce obesity.

The Time Is Ripe: Thinking about the Future Reduces Unhealthy Eating in Those with a Higher BMI

Research suggests that being oriented more towards the future (than the present) is correlated with healthier eating. However, this research tends to be correlational, and thus it is unclear whether inducing people to think about their future could increase healthy eating. Therefore, we investigated whether inducing people to think about their lives in the future versus the present would influence their intake of healthy (muesli) and unhealthy (Maltesers) food. Across two experiments, the effect of thinking about the future versus the present interacted with participants’ body mass index (BMI) to influence their consumption of unhealthy food, but no reliable effects were found for the consumption of healthy food. Among individuals with a higher BMI, thinking about their lives in the future resulted in lower consumption of the unhealthy food compared to thinking about their lives in the present. However, this effect was reversed for those with a lower BMI. In Experiment 2, we found no evidence that this effect was due to reduced impulsivity (as measured by a delay discounting task and a stop-signal task). This suggests that thinking about the future can reduce unhealthy eating among heavier people.

Episodic future thinking, delay discounting, and exercise during weight loss maintenance: The PACE trial

OBJECTIVES

Weight loss maintenance (WLM) is the next major challenge in obesity treatment. While most individuals who lose weight intend to keep their weight off, weight regain is common. Temporal Self-Regulation Theory posits that whether intentions lead to behavior depends on self-regulatory capacity, including delay discounting (DD; the tendency to discount a larger future reward in favor of a smaller immediate reward). Episodic Future Thinking (EFT; mental imagery of a future event for which a health goal is important) may improve DD and promote behavior change. Described herein is a trial protocol designed to examine whether EFT improves DD within the context of weight loss maintenance.

METHOD

Participants who lose ≥5% of initial body weight in an online behavioral weight loss intervention will be randomly assigned to a standard weight loss maintenance program (WLM-STD) or a weight loss maintenance program plus EFT (WLM + EFT). Both interventions involve periodic phone and in-person treatment sessions. Participants in WLM + EFT will engage in daily EFT training via smartphone. To control for contact, participants in WLM-STD will engage in daily Healthy Thinking (reviewing strategies for weight management) on their smartphone. Our primary hypothesis is that WLM + EFT will yield better improvements in DD compared to WLM-STD. We will also explore whether DD mediates the relationship between intervention allocation and physical activity (secondary outcome). Weight and contextual variables will be explored.

CONCLUSIONS

This study is the first to test whether EFT improves DD within the context of weight loss maintenance; results from this experimental medicine approach could have important implications for understanding the impact of both EFT and DD on sustained behavior change. (PsycInfo Database Record (c) 2020 APA, all rights reserved).