Self‐Control Moderates Decision‐Making Behavior When Minimizing Losses versus Maximizing Gains

We examined (1) whether people would be more responsive to the delayed consequences of their decisions when attempting to minimize losses than when attempting to maximize gains in a history‐dependent decision‐making task and (2) how trait self‐control would moderate such an effect. In two experiments, participants performed a dynamic decision‐making task where they chose one of two options on each trial. The increasing option always gave a smaller immediate reward but caused future rewards for both options to increase. The decreasing option always gave a larger immediate reward but caused future rewards for both options to decrease. In Experiment 1 where the two options had equivalent expected value in the long run, participants were more prone to select the increasing option, which yielded larger benefits on future trials, in the loss‐minimization condition than in the gain‐maximization condition. Trait self‐control moderated the effect of losses by enhancing the effect for low self‐control participants while attenuating it for high self‐control participants. In Experiment 2 where selecting the increasing option was suboptimal, low self‐control participants still attempted to reduce losses on future trials by selecting the increasing option more often than high self‐control participants. These results suggest that decision makers value delayed consequences of their actions more in a losses domain relative to a gains domain and low self‐control individuals are more susceptible to such an effect. Copyright © 2014 John Wiley & Sons, Ltd.     

Rewards decrease risky decisions for adolescent drivers: Implications for crash prevention

Motor vehicle crashes (MVCs) are a major contributor to adolescent mortality. Adolescent drivers are more likely to make risky decisions in the presence of peers. However, rewards have also been shown to improve decision making in adolescence. Our goal was to determine if peer observation and reward effects on decision-making were dependent upon adolescent driving styles.Twenty-four healthy adolescents played a driving game in a 2 (no peer; peer) × 2 (no rewards; rewards) within-subjects experiment. Driving styles were measured by self-report.Rewards favoring safe choices reduced risky decision making, but this effect was especially robust for adolescents with driving styles that increase risk of MVCs (i.e., dangerous, fast, angry, or distracted styles). Findings suggest that rewards for safe driving can be an effective mechanism for reducing MVCs, especially for the most at-risk drivers, if they can be made appetizing to adolescents.     

Mother still knows best: Maternal influence uniquely modulates adolescent reward sensitivity during risk taking

Adolescent decision‐making is highly sensitive to input from the social environment. In particular, adult and maternal presence influence adolescents to make safer decisions when encountered with risky scenarios. However, it is currently unknown whether maternal presence confers a greater advantage than mere adult presence in buffering adolescent risk taking. In the current study, 23 adolescents completed a risk‐taking task during an fMRI scan in the presence of their mother and an unknown adult. Results reveal that maternal presence elicits greater activation in reward‐related neural circuits when making safe decisions but decreased activation following risky choices. Moreover, adolescents evidenced a more immature neural phenotype when making risky choices in the presence of an adult compared to mother, as evidenced by positive functional coupling between the ventral striatum and medial prefrontal cortex. Our results underscore the importance of maternal stimuli in bolstering adolescent decision‐making in risky scenarios.     

Intact risk-based decision making in rats with prefrontal or accumbens dopamine depletion

The medial prefrontal cortex (mPFC) and the core region of the nucleus accumbens (AcbC) are key regions of a neural system that subserves risk-based decision making. Here, we examined whether dopamine (DA) signals conveyed to the mPFC and AcbC are critical for risk-based decision making. Rats with 6-hydroxydopamine or vehicle infusions into the mPFC or AcbC were examined in an instrumental task demanding probabilistic choice. In each session, probabilities of reward delivery after pressing one of two available levers were signaled in advance in forced trials followed by choice trials that assessed the animal??s preference. The probabilities of reward delivery associated with the large/risky lever declined systematically across four consecutive blocks but were kept constant within four subsequent daily sessions of a particular block. Thus, in a given session, rats need to assess the current value associated with the large/risky versus small/certain lever and adapt their lever preference accordingly. Results demonstrate that the assessment of within-session reward probabilities and probability discounting across blocks were not altered in rats with mPFC and AcbC DA depletions, relative to sham controls. These findings suggest that the capacity to evaluate the magnitude and likelihood of rewards associated with alternative courses of action seems not to rely on intact DA transmission in the mPFC or AcbC.     

Rhesus monkeys lack a consistent peak-end effect

In humans, the order of receiving sequential rewards can significantly influence the overall subjective utility of an outcome. For example, people subjectively rate receiving a large reward by itself significantly higher than receiving the same large reward followed by a smaller one (Do, Rupert, & Wolford, 2008). This result is called the peak-end effect. A comparative analysis of order effects can help determine the generality of such effects across primates, and we therefore examined the influence of reward-quality order on decision making in three rhesus macaque monkeys (Macaca mulatta). When given the choice between a high-low reward sequence and a low-high sequence, all three monkeys preferred receiving the high-value reward first. Follow-up experiments showed that for two of the three monkeys their choices depended specifically on reward-quality order and could not be accounted for by delay discounting. These results provide evidence for the influence of outcome order on decision making in rhesus monkeys. Unlike humans, who usually discount choices when a low-value reward comes last, rhesus monkeys show no such peak-end effect.     

Contributions of the nucleus accumbens and its subregions to different aspects of risk-based decision making

The nucleus accumbens (NAc) has been implicated in mediating different forms of decision making in humans and animals. In the present study, we observed that inactivation of the rat NAc, via infusion of GABA agonists, reduced preference for a large/risky option and increased response latencies on a probabilistic discounting task. Discrete inactivations of the NAc shell and core revealed further differences between these regions in mediating choice and response latencies, respectively. The effect on choice was attributable to reduced win–stay performance (i.e., choosing risky after a being rewarded for a risky choice on a preceding trial). Moreover, NAc inactivation altered choice only when the large/risky option had greater long-term value, in terms of the amount of food that could be obtained over multiple trials relative to the small/certain option. Inactivation of the NAc or the shell subregion also slightly reduced preference for larger rewards on a reward magnitude discrimination. Thus, the NAc seems to play a small role in biasing choice toward larger rewards, but its contribution to behavior is amplified when delivery of these rewards is uncertain, helping to direct response selection toward more favorable outcomes.     

With age comes wisdom: decision making in younger and older adults

In two experiments, younger and older adults performed decision-making tasks in which reward values available were either independent of or dependent on the previous sequence of choices made. The choice-independent task involved learning and exploiting the options that gave the highest rewards on each trial. In this task, the stability of the expected reward for each option was not influenced by the previous choices participants made. The choice-dependent task involved learning how each choice influenced future rewards for two options and making the best decisions based on that knowledge. Younger adults performed better when rewards were independent of choice, whereas older adults performed better when rewards were dependent on choice. These findings suggest a fundamental difference in the way in which younger adults and older adults approach decision-making situations. We discuss the results in the context of prominent decision-making theories and offer possible explanations based on neurobiological and behavioral changes associated with aging.     

Rhesus monkeys lack a consistent peak-end effect

In humans, the order of receiving sequential rewards can significantly influence the overall subjective utility of an outcome. For example, people subjectively rate receiving a large reward by itself significantly higher than receiving the same large reward followed by a smaller one (Do, Rupert, & Wolford, 2008). This result is called the peak-end effect. A comparative analysis of order effects can help determine the generality of such effects across primates, and we therefore examined the influence of reward-quality order on decision making in three rhesus macaque monkeys (Macaca mulatta). When given the choice between a high–low reward sequence and a low–high sequence, all three monkeys preferred receiving the high-value reward first. Follow-up experiments showed that for two of the three monkeys their choices depended specifically on reward-quality order and could not be accounted for by delay discounting. These results provide evidence for the influence of outcome order on decision making in rhesus monkeys. Unlike humans, who usually discount choices when a low-value reward comes last, rhesus monkeys show no such peak-end effect.     

Worth the wait: Children trade off delay and reward in self‐ and other‐benefiting decisions

Human prosocial behaviors are supported by early‐emerging psychological processes that detect and fulfill the needs of others. However, little is known about the mechanisms that enable children to deliver benefits to others at costs to the self, which requires weighing other‐regarding and self‐serving preferences. We used an intertemporal choice paradigm to systematically study and compare these behaviors in 5‐year‐old children. Our results show that other‐benefiting and self‐benefiting behavior share a common decision‐making process that integrates delay and reward. Specifically, we found that children sought to minimize delay and maximize reward, and traded off delays against rewards, regardless of whether these rewards were for the children themselves or another child. However, we found that children were more willing to invest their time to benefit themselves than someone else. Together, these findings show that from childhood, other‐ and self‐serving decisions are supported by a general mechanism that flexibly integrates information about the magnitude of rewards, and the opportunity costs of pursuing them. A video abstract of this article can be viewed at: https://youtu.be/r8S0DGe7f8Q     

氟哌啶醇与丙咪嗪交互作用对成本效益决策的影响

本实验采用T迷宫延迟奖赏模型研究多巴胺D2受体拮抗剂氟哌啶醇和5-羟色胺重摄取抑制剂丙咪嗪的交互作用对成本效益决策的影响, 同时探讨了延迟时间对决策的影响。T迷宫两臂分别设置为低成本-低奖赏端和高成本-高奖赏端。实验结果发现：氟哌啶醇能够降低大鼠选择高成本-高奖赏端的次数, 丙咪嗪则能够增加大鼠选择高成本-高奖赏端的次数; 在同时注射这两种药物情况下, 丙咪嗪能够抑制由氟哌啶醇引起的对低成本-低奖赏端的选择倾向。另外, 实验发现, 随延迟时间的增加大鼠选择高成本-高奖赏端的次数相对减少。由此可见, 丙咪嗪能够反转由氟哌啶醇导致的对低成本-低奖赏端的选择倾向, 这可能是由于细胞间5-羟色胺含量的升高部分反转了由多巴胺系统受损导致的行为倾向; 延迟时间的改变可对决策倾向产生逆转, 因此成本的支出即延迟时间也是影响成本效益决策的重要因素。     

Scaling Incentives: Determining Preference and Indifference in 8- to lO-Year-Old Girls

The present study adopted procedures similar to those used by Logan (1965) to determine choice behavior in children. The objective was to provide an improved methodology in delay-of-gratification studies, thus avoiding the problems associated with scaling different kinds of rewards, and to provide approximate functions relating a delay-of-token reward to choice behavior. Thus, 7 girls aged 8 to 10 years were exposed to a choice paradigm in which a larger reward (2 tokens) was pitted against a smaller reward (1 token); access to these rewards was delayed a certain period of time. The results of this experiment showed that as the delay of the larger reward increased, preference for the smaller reward increased in an orderly fashion. The finding that delay shifted preference from the larger to the smaller reward is discussed in relation to current theory. The results of this experiment also provide evidence for the utility of tokens in scaling incentives for choice studies.     

Developmental patterns of change in the influence of safe and risky peer choices on risky decision‐making

Adolescents take more risks when peers monitor their behavior. However, it is largely unknown how different types of peer influence affect adolescent decision‐making. In this study, we investigate how information about previous choices of peers differentially influences decision‐making in adolescence and young adulthood. Participants (N = 99, age range 12–22) completed an economic choice task in which choice options were systematically varied on levels of risk and ambiguity. On each trial, participants selected between a safer choice (low variability in outcome) and a riskier choice (high variability in outcome). Participants made choices in three conditions: a solo condition in which they made choices with no additional information, a social condition in which they saw choices of supposed peers, and a computer condition in which they saw choices of a computer. Results showed that participants’ choices conform to the choices made by the peers, but not a computer. Furthermore, when peers chose the safe option, late adolescents were especially likely to make a safe choice. Conversely, when the peer made a risky choice, late adolescents were least likely to follow choices made by the peer. We did not find evidence for differential influence of social information on decisions depending on their level of risk and ambiguity. These results show that information about previous decisions of peers are a powerful modifier for behavior and that the effect of peers on adolescents’ decisions is less ubiquitous and more specific than previously assumed.     

Children's Sensitivity to Cost and Reward in Decision Making across Distinct Domains of Probability,Effort, and Delay

Many behavioral paradigms used to study individuals' decision‐making tendencies do not capture the decision components that contribute to behavioral outcomes, such as differentiating decisions driven toward a reward from decisions driven away from a cost. This study tested a novel decision‐making task in a sample of 403 children (age 9 years) enrolled in an ongoing longitudinal study. The task consisted of three blocks representing distinct cost domains (delay, probability, and effort), wherein children were presented with a deck of cards, each of which consisted of a reward and a cost. Children elected whether to accept or skip the card at each trial. Reward–cost pairs were selected by using an adaptive algorithm to strategically sample the decision space in the fewest number of trials. Using person‐specific regression models, decision preferences were quantified for each cost domain with respect to general tolerance (intercept), as well as parameters estimating the effect of incremental increases in reward or cost on the probability of accepting a card. Results support the relative independence of decision‐making tendencies across cost domains, with moderate correlations observed between tolerance for delay and effort. Specific decision parameters showed unique associations with cognitive and behavioral measures including executive function, academic motivation, anxiety, and hyperactivity. Evidence indicates that sensitivity to reward is an important factor in incentivizing decisions to work harder or wait longer. Dissociating the relative contributions of reward and cost sensitivity in multiple domains may facilitate the identification of heterogeneity in suboptimal decision making. Copyright © 2017 John Wiley & Sons, Ltd.     

Affect regulation and temporal discounting: interactions between primed, state, and trait affect

Previous research has largely focused on the influence of experienced affect on decision making; however, other sources of affective information may also shape decisions. In two studies, we examine the interacting influences of affective information, state affect, and personality on temporal discounting rates (i.e., the tendency to choose small rewards today rather than larger rewards in the future). In Study 1, participants were primed with either positive or negative affect adjectives before making reward choices. In Study 2, participants underwent either a positive or negative affect induction before making reward choices. Results in both studies indicate that neuroticism interacts with state unpleasant affect and condition (i.e., positive or negative primes or induction) to predict discounting rates. Moreover, the nature of the interactions depends on the regulatory cues of the affective information available. These results suggest that irrelevant (i.e., primes) and stable (i.e., personality traits) sources of affective information also shape judgments and decision making. Thus, current affect levels are not the only source of affective information that guides individuals when making decisions.     

High temporal discounters overvalue immediate rewards rather than undervalue future rewards: An event-related brain potential study

Impulsivity is characterized in part by heightened sensitivity to immediate relative to future rewards. Although previous research has suggested that “high discounters” in intertemporal choice tasks tend to prefer immediate over future rewards because they devalue the latter, it remains possible that they instead overvalue immediate rewards. To investigate this question, we recorded the reward positivity, a component of the event-related brain potential (ERP) associated with reward processing, with participants engaged in a task in which they received both immediate and future rewards and nonrewards. The participants also completed a temporal discounting task without ERP recording. We found that immediate but not future rewards elicited the reward positivity. High discounters also produced larger reward positivities to immediate rewards than did low discounters, indicating that high discounters relatively overvalued immediate rewards. These findings suggest that high discounters may be more motivated than low discounters to work for monetary rewards, irrespective of the time of arrival of the incentives.     

Evidence for a magnitude effect in temporal discounting with pigeons

A magnitude effect in human intertemporal choice is well established-larger rewards or outcomes are discounted over time at a lower rate than are smaller rewards. However, many recent studies have failed to find a corresponding effect in nonhuman animals. Here we report a magnitude effect in temporal discounting for pigeons' choices involving a tradeoff between reward delay and amount. Pigeons chose between a small reward (1-s access to food) after a 2-s delay, and a large reward (4.5-s access to food) after a 28-s delay. Across conditions, the delays to the small and large rewards were increased or decreased, respectively. Temporal discounting functions obtained through a value-estimation procedure showed clear evidence of a magnitude effect: The value of the large reward decreased more slowly with increasing delay than the value of the small reward. We linked this result to a nonlinear relationship between choice and the delays associated with the small and large rewards. The nonlinearity was contrary to the generalized matching law but was predicted by the contextual choice model. Our results confirm the existence of a magnitude effect in nonhuman temporal discounting, showing that this adaptation is not unique to humans.     

Eye blink rate predicts reward decisions in adolescents

The ventral striatum displays hyper‐responsiveness to reward in adolescents relative to other age groups, and animal research on the developmental trajectory of the dopaminergic system suggests that dopamine may underlie adolescent sensitivity to reward. However, practical limitations prevent the direct measurement of dopamine in healthy adolescents. Eye blink rate (EBR) shows promise as a proxy measure of striatal dopamine D2 receptor function. We investigated developmental differences in the relationship between EBR and reward‐seeking behavior on a risky decision‐making task. Increasing EBR was associated with greater reward maximization on the task for adolescent but not adult participants. Furthermore, adolescents demonstrated greater sensitivity to reward value than adults, as evinced by shifts in decision patterns based on increasing potential reward. These findings suggest that previously observed adolescent behavioral and neural hypersensitivity to reward may in fact be due to greater dopamine receptor activity, as represented by the relationship of blink rate and reward‐seeking behavior. They also demonstrate the feasibility and utility of using EBR as a proxy for dopamine in healthy youth in whom direct measurements of dopamine are prohibitively invasive.     

Behavioral and neural predictors of upcoming decisions

Although it is widely known that brain regions such as the prefrontal cortex, the amygdala, and the ventral striatum play large roles in decision making, their precise contributions remain unclear. Here, we used functional magnetic resonance imaging and principles of reinforcement learning theory to investigate the relationship between current reinforcements and future decisions. In the experiment, subjects chose between high-risk (i.e., low probability of a large monetary reward) and low-risk (high probability of a small reward) decisions. For each subject, we estimated value functions that represented the degree to which reinforcements affected the value of decision options on the subsequent trial. Individual differences in value functions predicted not only trial-to-trial behavioral strategies, such as choosing high-risk decisions following high-risk rewards, but also the relationship between activity in prefrontal and subcortical regions during one trial and the decision made in the subsequent trial. These findings provide a novel link between behavior and neural activity by demonstrating that value functions are manifested both in adjustments in behavioral strategies and in the neural activity that accompanies those adjustments.     

A new framework for modeling decisions about changing information: The Piecewise Linear Ballistic Accumulator model

In the real world, decision making processes must be able to integrate non-stationary information that changes systematically while the decision is in progress. Although theories of decision making have traditionally been applied to paradigms with stationary information, non-stationary stimuli are now of increasing theoretical interest. We use a random-dot motion paradigm along with cognitive modeling to investigate how the decision process is updated when a stimulus changes. Participants viewed a cloud of moving dots, where the motion switched directions midway through some trials, and were asked to determine the direction of motion. Behavioral results revealed a strong delay effect: after presentation of the initial motion direction there is a substantial time delay before the changed motion information is integrated into the decision process. To further investigate the underlying changes in the decision process, we developed a Piecewise Linear Ballistic Accumulator model (PLBA). The PLBA is efficient to simulate, enabling it to be fit to participant choice and response-time distribution data in a hierarchal modeling framework using a non-parametric approximate Bayesian algorithm. Consistent with behavioral results, PLBA fits confirmed the presence of a long delay between presentation and integration of new stimulus information, but did not support increased response caution in reaction to the change. We also found the decision process was not veridical, as symmetric stimulus change had an asymmetric effect on the rate of evidence accumulation. Thus, the perceptual decision process was slow to react to, and underestimated, new contrary motion information.     

Nudge to Health: Harnessing Decision Research to Promote Health Behavior

We review selected literature that examines how biases in decision making can be utilized to encourage individual health behavior, such as vaccination, and promote policy decisions, such as resource allocation. These studies use simple interventions to nudge people towards more optimal health decisions without restricting decision‐makers’ freedom of choice. Examples include framing effects, defaults, implementation intentions, position effects, social norm, incentives, and emotions. We suggest that nudges are an effective way to promote healthy behavior.