A Case Series of Air Force Pararescue Long-Range Ocean Rescues.

BACKGROUND: US Air Force (USAF) pararescuemen (PJs) perform long-range ocean rescue missions for ill or injured civilians when advanced care and transport are not available. The purpose of this case series is to examine the details of these missions, review patient treatments and outcomes, and describe common tactics, techniques, and procedures for these missions. METHODS: Cases in which the USAF PJs preformed long-range ocean rescue for critically ill or injured civilians between 2011 and 2018 were identified. Case information was obtained, including patient demographics, location, infiltration/exfiltration methods, diagnoses, treatments, duration of patient care, patient outcome, and lessons learned. RESULTS: A total of 14 pararescue missions involving 22 civilians were identified for analysis. Of the 22 patients, 10 (45%) suffered burns, six (27%) had abdominal issues, four (18%) had musculoskeletal injuries, one had a traumatic brain injury, and one had a necrotizing soft-tissue infection. Medical care of these patients included intravenous fluid and blood product resuscitation, antibiotics, analgesics, airway management, and escharotomy. The median duration of patient care was 51 hours. CONCLUSION: This case series illustrates the complex transportation requirements, patient and gear logistical challenges, austere medicine, and prolonged field care (PFC) unique to USAF PJ open-water response.

Promises and lies: can observers detect deception in written messages.

We design a laboratory experiment to examine predictions of trustworthiness in a novel three-person trust game. We investigate whether and why observers of the game can predict the trustworthiness of hand-written communications. Observers report their perception of the trustworthiness of messages, and make predictions about the senders' behavior. Using observers' decisions, we are able to classify messages as "promises" or "empty talk." Drawing from substantial previous research, we hypothesize that certain factors influence whether a sender is likely to honor a message and/or whether an observer perceives the message as likely to behonored: the mention of money; the use of encompassing words; and message length. We find that observers have more trust in longer messages and "promises"; promises that mention money are significantly more likely to be broken; and observers trust equally in promises that do and do not mention money. Overall, observers perform slightly better than chance at predicting whether a message will be honored. We attribute this result to observers' ability to distinguish promises from empty talk, and to trust promises more than empty talk. However, within each of these two categories, observers are unable to discern between messages that senders will honor from those that they will not.

An experimental analysis of acquired impulse control among adult humans intolerant to alcohol.

The ability to control tempting impulses impacts health, education, and general socioeconomic outcomes among people at all ages. Consequently, whether and how impulse control develops in adult populations is a topic of enduring interest. Although past research has shed important light on this question using controlled intervention studies, here we take advantage of a natural experiment in China, where males but not females encounter substantial social pressure to consume alcohol. One-third of our sample, all of whom are Han Chinese, is intolerant to alcohol, whereas the remaining control sample is observationally identical but alcohol tolerant. Consistent with previous literature, we find that intolerant males are significantly more likely to exercise willpower to limit their alcohol consumption than alcohol-tolerant males. In view of the strength model of self-control, we hypothesize that this enables improved impulse control in other contexts as well. To investigate this hypothesis, we compare decisions in laboratory games of self-control between the tolerant and intolerant groups. We find that males intolerant to alcohol and who regularly encounter drinking environments control their selfish impulses significantly better than their tolerant counterparts. On the other hand, we find that female Han Chinese intolerant to alcohol do not use self-control to limit alcohol consumption more than tolerant females, nor do the tolerant and intolerant females exhibit differences in self-control behaviors. Our research indicates that impulse control can be developed in adult populations as a result of self-control behaviors in natural environments, and shows that this skill has generalizable benefits across behavioral domains.

Everybody else is doing it: exploring social transmission of lying behavior.

Lying is a common occurrence in social interactions, but what predicts whether an individual will tell a lie? While previous studies have focused on personality factors, here we asked whether lying tendencies might be transmitted through social networks. Using an international sample of 1,687 socially connected pairs, we investigated whether lying tendencies were related in socially connected individuals, and tested two moderators of observed relationships. Participants recruited through a massive open online course reported how likely they would be to engage in specific lies; a friend or relative responded to the same scenarios independently. We classified lies according to their beneficiary (antisocial vs. prosocial lies), and their directness (lies of commission vs. omission), resulting in four unique lying categories. Regression analyses showed that antisocial commission, antisocial omission, and prosocial commission lying tendencies were all uniquely related in connected pairs, even when the analyses were limited to pairs that were not biologically related. For antisocial lies of commission, these relationships were strongest, and were moderated by amount of time spent together. Randomly paired individuals from the same countries were also related in their antisocial commission lying tendencies, signifying country-level norms. Our results indicate that a person's lying tendencies can be predicted by the lying tendencies of his or her friends and family members.

Dissociable contribution of prefrontal and striatal dopaminergic genes to learning in economic games.

Game theory describes strategic interactions where success of players' actions depends on those of coplayers. In humans, substantial progress has been made at the neural level in characterizing the dopaminergic and frontostriatal mechanisms mediating such behavior. Here we combined computational modeling of strategic learning with a pathway approach to characterize association of strategic behavior with variations in the dopamine pathway. Specifically, using gene-set analysis, we systematically examined contribution of different dopamine genes to variation in a multistrategy competitive game captured by (i) the degree players anticipate and respond to actions of others (belief learning) and (ii) the speed with which such adaptations take place (learning rate). We found that variation in genes that primarily regulate prefrontal dopamine clearance--catechol-O-methyl transferase (COMT) and two isoforms of monoamine oxidase--modulated degree of belief learning across individuals. In contrast, we did not find significant association for other genes in the dopamine pathway. Furthermore, variation in genes that primarily regulate striatal dopamine function--dopamine transporter and D2 receptors--was significantly associated with the learning rate. We found that this was also the case with COMT, but not for other dopaminergic genes. Together, these findings highlight dissociable roles of frontostriatal systems in strategic learning and support the notion that genetic variation, organized along specific pathways, forms an important source of variation in complex phenotypes such as strategic behavior.

Neural signatures of betrayal aversion: an fMRI study of trust.

Decisions are said to be 'risky' when they are made in environments with uncertainty caused by nature. By contrast, a decision is said to be 'trusting' when its outcome depends on the uncertain decisions of another person. A rapidly expanding literature reveals economically important differences between risky and trusting decisions, and further suggests these differences are due to 'betrayal aversion'. While its neural foundations have not been previously illuminated, the prevailing hypothesis is that betrayal aversion stems from a desire to avoid negative emotions that arise from learning one's trust was betrayed. Here, we provide evidence from an fMRI study that supports this hypothesis. In particular, our data indicate that the anterior insula modulates trusting decisions that involve the possibility of betrayal.

Cooperation during cultural group formation promotes trust towards members of out-groups.

People often cooperate with members of their own group, and discriminate against members of other groups. Previous research establishes that cultural groups can form endogenously, and that these groups demonstrate in-group favouritism. Given the presence of cultural groups, the previous literature argues that cultural evolution selects for groups that exhibit parochial altruism. The source of initial variation in these traits, however, remains uninformed. We show here that a group's economic production environment may substantially influence parochial tendencies, with groups formed around more cooperative production (CP) displaying less parochialism than groups formed around more independent production (IP) processes. Participants randomized into CP and IP production tasks formed cultural groups, and subsequently played hidden-action trust games with in-group and out-group trustees. We found CP to be associated with significantly greater sharing and exchanging behaviours than IP. In trust games, significant parochial altruism (in-group favouritism combined with out-group discrimination) was displayed by members of IP groups. By contrast, members of CP groups did not engage in either in-group favouritism or out-group discrimination. Further, we found the absence of out-group discrimination in CP to persist even following 'betrayal'. Finally, belief data suggest that members of CP are not more intrinsically generous than IP members, but rather more likely to believe that out-group trustees will positively reciprocate. Our results have important implications for anyone interested in building cooperative teams, and shed new light on connections between culture and cooperation.

The causal effect of market priming on trust: an experimental investigation using randomized control.

We report data from laboratory experiments where participants were primed using phrases related to markets and trade. Participants then participated in trust games with anonymous strangers. The decisions of primed participants are compared to those of a control group. We find evidence that priming for market participation affects positively the beliefs regarding the trustworthiness of anonymous strangers and increases trusting decisions.

Temptation at work.

To encourage worker productivity, companies routinely adopt policies requiring employees to delay gratification. For example, offices might prohibit use of the internet for personal purposes during regular business hours. Recent work in social psychology, however, suggests that using willpower to delay gratification can negatively impact performance. We report data from an experiment where subjects in a Willpower Treatment are asked to resist the temptation to join others in watching a humorous video for 10 minutes. In relation to a baseline treatment that does not require willpower, we show that resisting this temptation detrimentally impacts economic productivity on a subsequent task.

Private and public decisions in social dilemmas: evidence from children's behavior.

Are selfish impulses less likely to be pursued when decisions are publicly observable? Is the presence of peers a potential solution to social dilemmas? In this paper we report data on the self-control decisions of children aged 6 to 11 who participated in games that require one to resist a selfish impulse for several minutes in order to benefit others. In Public Condition children make decisions in public view of the group of other participants, while in Private Condition they have the possibility to decide privately. We find that children aged 9 and higher are better able to resist selfish impulses in public environments. Younger children, however, display no such effect. Further, we find self-control substantially impacted by group size. When decisions are public, self-control is better in larger groups, while in private condition the opposite holds.

Competition for trophies triggers male generosity.

BACKGROUND: Cooperation is indispensable in human societies, and much progress has been made towards understanding human pro-social decisions. Formal incentives, such as punishment, are suggested as potential effective approaches despite the fact that punishment can crowd out intrinsic motives for cooperation and detrimentally impact efficiency. At the same time, evolutionary biologists have long recognized that cooperation, especially food sharing, is typically efficiently organized in groups living on wild foods, even absent formal economic incentives. Despite its evident importance, the source of this voluntary compliance remains largely uninformed. Drawing on costly signaling theory, and in light of the widely established competitive nature of males, we hypothesize that unique and displayable rewards (trophies) out of competition may trigger male generosity in competitive social environments. PRINCIPAL FINDINGS: Here, we use a controlled laboratory experiment to show that cooperation is sustained in a generosity competition with trophy rewards, but breaks down in the same environment with equally valuable but non-unique and non-displayable rewards. Further, we find that males' competition for trophies is the driving force behind treatment differences. In contrast, it appears that female competitiveness is not modulated by trophy rewards. SIGNIFICANCE: Our results suggest new approaches to promoting cooperation in human groups that, unlike punishment mechanisms, do not sacrifice efficiency. This could have important implications in any domain where voluntary compliance matters--including relations between spouses, employers and employees, market transactions, and conformity to legal standards.

Beneficial betrayal aversion.

Many studies demonstrate the social benefits of cooperation. Likewise, recent studies convincingly demonstrate that betrayal aversion hinders trust and discourages cooperation. In this respect, betrayal aversion is unlike socially "beneficial" preferences including altruism, fairness and inequity aversion, all of which encourage cooperation and exchange. To our knowledge, other than the suggestion that it acts as a barrier to rash trust decisions, the benefits of betrayal aversion remain largely unexplored. Here we use laboratory experiments with human participants to show that groups including betrayal-averse agents achieve higher levels of reciprocity and more profitable social exchange than groups lacking betrayal aversion. These results are the first rigorous evidence on the benefits of betrayal aversion, and may help future research investigating cultural differences in betrayal aversion as well as future research on the evolutionary roots of betrayal aversion. Further, our results extend the understanding of how intentions affect social interactions and exchange and provide an effective platform for further research on betrayal aversion and its effects on human behavior.

Emotion regulation and decision making under risk and uncertainty.

It is well established that emotion plays a key role in human social and economic decision making. The recent literature on emotion regulation (ER), however, highlights that humans typically make efforts to control emotion experiences. This leaves open the possibility that decision effects previously attributed to acute emotion may be a consequence of acute ER strategies such as cognitive reappraisal and expressive suppression. In Study 1, we manipulated ER of laboratory-induced fear and disgust, and found that the cognitive reappraisal of these negative emotions promotes risky decisions (reduces risk aversion) in the Balloon Analogue Risk Task and is associated with increased performance in the prehunch/hunch period of the Iowa Gambling Task. In Study 2, we found that naturally occurring negative emotions also increase risk aversion in Balloon Analogue Risk Task, but the incidental use of cognitive reappraisal of emotions impedes this effect. We offer evidence that the increased effectiveness of cognitive reappraisal in reducing the experience of emotions underlies its beneficial effects on decision making.

Neural responses to sanction threats in two-party economic exchange.

Sanctions are used ubiquitously to enforce obedience to social norms. However, recent field studies and laboratory experiments have demonstrated that cooperation is sometimes reduced when incentives meant to promote prosocial decisions are added to the environment. Although various explanations for this effect have been suggested, the neural foundations of the effect have not been fully explored. Using a modified trust game, we found that trustees reciprocate relatively less when facing sanction threats, and that the presence of sanctions significantly reduces trustee's brain activities involved in social reward valuation [in the ventromedial prefrontal cortex (VMPFC), lateral orbitofrontal cortex, and amygdala] while it simultaneously increases brain activities in the parietal cortex, which has been implicated in rational decision making. Moreover, we found that neural activity in a trustee's VMPFC area predicts her future level of cooperation under both sanction and no-sanction conditions, and that this predictive activity can be dynamically modulated by the presence of a sanction threat.

Anxiety impairs decision-making: psychophysiological evidence from an Iowa Gambling Task.

Using the Iowa Gambling Task (IGT) and psychophysiological correlates of emotional responses (i.e., heart rate and skin conductance), we investigate the effects of trait anxiety (TA) on decision-making. We find that high TA is associated with both impaired decision-making and increased anticipatory physiological (somatic) responses prior to advantageous trials. For both high and low TA, skin conductance responses preceding advantageous trials predict decisions. At the same time, somatic responses to choice outcomes reflect differences between high and low TA sensitivities to punishments and rewards. The pattern of impaired decision-making and increased somatic markers that we find in high TA may have important implications for neuropsychological decision theory. In particular, it offers an example of defective modulation of somatic signals, coupled with disrupted discrimination of advantageous and disadvantageous choices.

Introduction to neuroeconomics.

Neuroeconomics has quickly attracted the attention of economists, psychologists, and neuroscientists. These scholars have joined to combine experimental methods and mathematical models from which novel results on brain and behavior have emerged. In this book the authors, who represent the cutting edge of this new discipline, draw connections between research in neuroeconomics and health economics. Moreover, they direct interested readers to a goldmine of additional references. Much of the research discussed here offers more questions than answers, and many of the answers are tentative first steps at a new understanding. It is precisely this that fuels our excitement about neuroeconomics.

Anxiety and decision-making: toward a neuroeconomics perspective.

PURPOSE: This chapter focuses on individual differences in anxiety, by reviewing its neurobiology, cognitive effects, with an emphasis on decision-making, and recent developments in neuroeconomics. METHODOLOGY: A review and discussion of anxiety and decision-making research. PRACTICAL IMPLICATIONS: This chapter argues that by making the step from emotional states to individual differences in emotion, neuroeconomics can extend its neurobiological roots and outreach its current clinical relevance. VALUE OF CHAPTER: This chapter contributes to the literature on individual differences in emotion and their effects on decision-making, which is increasingly important in mainstream behavioral economics and neuroeconomics.

Expectations mediate objective physiological placebo effects.

PURPOSE: A placebo effect is a (positive) change in health outcomes that is due to a (positive) change in beliefs about the value of a treatment. Placebo effects might be "behavioral," in the sense that revised beliefs lead to behavioral changes or new actions that in turn yield changes in health outcomes. Placebo effects might also include a "physiological" component, which refers broadly to non-behavioral, brain-modulated mechanisms by which new beliefs cause changes in health outcomes. Nearly all formal economic models of human behavior are consistent with behavioral placebo effects, but strongly inconsistent with their physiological counterparts. The reason is that the latter effects can imply that expectations enter, rather than multiply, state-contingent preferences. It is therefore unfortunate that little evidence exists on physiological placebo effects. We report data from novel clinical experiments with caffeine that seek to provide such evidence. METHODS: Subjects visit the clinic on multiple occasions. On each visit they ingest either a placebo or caffeine pill. Subjects only know the probability with which the pill includes caffeine. We obtain physiological measurements prior to ingestion and at 30, 60, and 90 min after ingestion. Importantly, we constrain subjects to remain seated and read preselected magazines during the interval between treatment and outcome measurement. FINDINGS: Our design provides particularly clean inference because it (i) eliminates the possibility of behavioral confounds; (ii) provides for measurements at the individual level; (iii) manipulates beliefs without deception; and (iv) uses salient rewards. We find evidence for the existence of physiological placebo effects mediated by expectations. IMPLICATIONS: Our results are consistent with the possibility that the prefrontal cortex provides external, top-down control that modulates physiological outcomes, and make a case for the importance of research geared toward developing appropriate and tractable frameworks that accommodate non-linear relationships between expectations and preferences.

Emotion expression in human punishment behavior.

Evolutionary theory reveals that punishment is effective in promoting cooperation and maintaining social norms. Although it is accepted that emotions are connected to punishment decisions, there remains substantial debate over why humans use costly punishment. Here we show experimentally that constraints on emotion expression can increase the use of costly punishment. We report data from ultimatum games, where a proposer offers a division of a sum of money and a responder decides whether to accept the split, or reject and leave both players with nothing. Compared with the treatment in which expressing emotions directly to proposers is prohibited, rejection of unfair offers is significantly less frequent when responders can convey their feelings to the proposer concurrently with their decisions. These data support the view that costly punishment might itself be used to express negative emotions and suggest that future studies will benefit by recognizing that human demand for emotion expression can have significant behavioral consequences in social environments, including families, courts, companies, and markets.

Experiments investigating cooperative types in humans: a complement to evolutionary theory and simulations.

Unlike other species, humans cooperate in large, distantly related groups, a fact that has long presented a puzzle to biologists. The pathway by which adaptations for large-scale cooperation among nonkin evolved in humans remains a subject of vigorous debate. Results from theoretical analyses and agent-based simulations suggest that evolutionary dynamics need not yield homogeneous populations, but can instead generate a polymorphic population that consists of individuals who vary in their degree of cooperativeness. These results resonate with the recent increasing emphasis on the importance of individual differences in understanding and modeling behavior and dynamics in experimental games and decision problems. Here, we report the results of laboratory experiments that complement both theory and simulation results. We find that our subjects fall into three types, an individual's type is stable, and a group's cooperative outcomes can be remarkably well predicted if one knows its type composition. Reciprocal types, who contribute to the public good as a positive function of their beliefs about others' contributions, constitute the majority (63%) of players; cooperators and free-riders are also present in our subject population. Despite substantial behavioral differences, earnings among types are statistically identical. Our results support the view that our human subject population is in a stable, polymorphic equilibrium of types.