I'm too calm-Let's take a risk! On the impact of state and trait arousal on risk taking

Trait impulsivity influences behavioural and physiological responses to threat in a virtual environment

Trait impulsivity represents a tendency to take action without forethought or consideration of consequences. This trait is multifaceted and can be decomposed into attentional, motor and non-planning subtypes of impulsivity. The purpose of the current study was to investigate how subtypes of trait impulsivity responded to different degrees of threat within room-scale virtual reality (VR) with respect to behaviour and level of physiological activation. Thirty-four participants were required to negotiate a virtual environment (VE) where they walked at height with the continuous threat of a virtual 'fall.' Behavioural measures related to the speed of movement, interaction frequency and risk were collected. Participants also wore ambulatory sensors to collect data from electrocardiogram (ECG) and electrodermal activity (EDA). Our results indicated that participants who scored highly on non-planning impulsivity exhibited riskier behaviour and higher skin conductance level (SCL). Participants with higher motor impulsivity interacted with more objects in the VE when threat was high, they also exhibited contradictory indicators of physiological activation. Attentional impulsivity was associated with a greater number of falls across the VE. The results demonstrate that subtypes of trait impulsivity respond to threats via different patterns of behaviour and levels of physiological activation, reinforcing the multifaceted nature of the trait.

Daily Affect and Daily Prospective Memory in People after Stroke and Their Partners: The Moderating Role of Resting Heart Rate

INTRODUCTION

Experimental research suggests that affect may influence prospective memory performance, but real-life evidence on affect-prospective memory associations is limited. Moreover, most studies have examined the valence dimension of affect in understanding the influence of affect on cognitive performance in daily life, with insufficient consideration of the arousal dimension. To maximize ecological validity, the current study examined the relationships between daily affect and daily prospective memory using repeated daily assessments and the role of resting heart rate on these relationships. We examined both valence and arousal of daily affect by categorizing affect into four dimensions: high-arousal positive affect, low-arousal positive affect, high-arousal negative affect, and low-arousal negative affect.

METHOD

We examined existing data collected from community-dwelling couples, of which at least one partner had a stroke history. The analytic sample included 111 adults (Mage = 67.46 years, SD = 9.64; 50% women) who provided 1,274 days of data. Among the participants, 58 were living with the effects of a stroke and 53 were partners. Participants completed daily event-based prospective memory tasks (in morning and/or evening questionnaires), reported daily affect in the evening, and wore a wrist-based Fitbit device to monitor resting heart rate over 14 consecutive days.

RESULTS

Results from multilevel models show that, within persons, elevated high-arousal negative affect was associated with worse daily prospective memory performance. In addition, lower resting heart rate attenuated the inverse association between high-arousal negative affect and lowered prospective memory performance. We did not find significant associations of high- or low-arousal positive affect and low-arousal negative affect with daily prospective memory.

DISCUSSION

Our findings are in line with the resource allocation model and the cue-utilization hypothesis in that high-arousal negative affect is detrimental to daily prospective memory performance. Lower resting heart rate may buffer individuals' prospective memory performance from the influence of high-arousal negative affect. These findings are consistent with the neurovisceral integration model on heart-brain connections, highlighting the possibility that cardiovascular fitness may help maintain prospective memory into older adulthood.

Intertemporal Decision-making and Risk Decision-making Among Habitual Nappers Under Nap Sleep Restriction: A Study from ERP and Time-frequency

Sleep restriction affects people's decision-making behavior. Nap restriction is a vital subtopic within sleep restriction research. In this study, we used EEG to investigate the impact of nap sleep restriction on intertemporal decision-making (Study 1) and decision-making across risky outcomes (Study 2) from ERP and time-frequency perspectives. Study 1 found that habitual nappers restricting their naps felt more inclined to choose immediate, small rewards over delayed, large rewards in an intertemporal decision-making task. P200s, P300s, and LPP in our nap-restriction group were significantly higher than those in the normal nap group. Time-frequency results showed that the delta band (1 ~ 4 Hz) power of the restricted nap group was significantly higher than that of the normal nap group. In Study 2, the nap-restriction group was more likely to choose risky options. P200s, N2s, and P300s in the nap deprivation group were significantly higher than in the normal nap group. Time-frequency results also found that the beta band (11 ~ 15 Hz) power of the restricted nap group was significantly lower than that of the normal nap group. The habitual nappers became more impulsive after nap restriction and evinced altered perceptions of time. The time cost of the LL (larger-later) option was perceived to be too high when making intertemporal decisions, and their expectation of reward heightened when making risky decisions-believing that they had a higher probability of receiving a reward. This study provided electrophysiological evidence for the dynamic processing of intertemporal decision-making, risky decision-making, and the characteristics of nerve concussions for habitual nappers.

The catecholamine precursor Tyrosine reduces autonomic arousal and decreases decision thresholds in reinforcement learning and temporal discounting

Supplementation with the catecholamine precursor L-Tyrosine might enhance cognitive performance, but overall findings are mixed. Here, we investigate the effect of a single dose of tyrosine (2g) vs. placebo on two catecholamine-dependent trans-diagnostic traits: model-based control during reinforcement learning (2-step task) and temporal discounting, using a double-blind, placebo-controlled, within-subject design (n = 28 healthy male participants). We leveraged drift diffusion models in a hierarchical Bayesian framework to jointly model participants' choices and response times (RTS) in both tasks. Furthermore, comprehensive autonomic monitoring (heart rate, heart rate variability, pupillometry, spontaneous eye blink rate) was performed both pre- and post-supplementation, to explore potential physiological effects of supplementation. Across tasks, tyrosine consistently reduced participants' RTs without deteriorating task-performance. Diffusion modeling linked this effect to attenuated decision-thresholds in both tasks and further revealed increased model-based control (2-step task) and (if anything) attenuated temporal discounting. On the physiological level, participants' pupil dilation was predictive of the individual degree of temporal discounting. Tyrosine supplementation reduced physiological arousal as revealed by increases in pupil dilation variability and reductions in heart rate. Supplementation-related changes in physiological arousal predicted individual changes in temporal discounting. Our findings provide first evidence that tyrosine supplementation might impact psychophysiological parameters, and suggest that modeling approaches based on sequential sampling models can yield novel insights into latent cognitive processes modulated by amino-acid supplementation.

Feeling Safe With Hypnosis: Eliciting Positive Feelings During a Special State of Consciousness

Our state of consciousness is crucial for our ability to follow suggestions. Suggestions in turn are a powerful tool to induce positive emotional states. In my research, I suggest positive feelings of safety during hypnosis. This is a positive emotional state of low arousal and low anxiety. Both arousal and anxiety affect our decision-making. However, when we feel safe due to hypnotic suggestions of safety, we do not act riskier. Instead, EEG brain activity shows that monetary rewards get less important and delayed rewards are less devalued compared to immediate rewards when we feel safe. These results open promising perspectives for the use of hypnosis to reduce impulsive behavior, for example, in substance abuse. Therapeutic suggestions of safety even work in highly stressful environments like the intensive care unit. I showed that patients tolerate non-invasive ventilation much better when they get the suggestion to feel safe. The effects of positive therapeutic suggestions delivered during hypnosis even persist over time. Post-hypnotic suggestions are associations between a certain emotional state and a trigger that elicits this emotional state after hypnosis is over. I showed that post-hypnotic suggestions of safety are effective weeks after the therapeutic session. Therefore, I present a therapeutic technique that uses a special state of consciousness, hypnosis, to induce positive emotional states. The effects of this technique are very strong and long lasting. My goal is to provide scientific evidence for the use of hypnotherapeutic techniques to increase the number of people who apply and profit from them.

Risky Decision Making Under Stressful Conditions: Men and Women With Smaller Cortisol Elevations Make Riskier Social and Economic Decisions

Men often make riskier decisions than women across a wide range of real-life behaviors. Whether this sex difference is accentuated, diminished, or stable under stressful conditions is, however, contested in the scientific literature. A critical blind spot lies amid this contestation: Most studies use standardized, laboratory-based, cognitive measures of decision making rather than complex real-life social simulation tasks to assess risk-related behavior. To address this blind spot, we investigated the effects of acute psychosocial stress on risk decision making in men and women (N = 80) using a standardized cognitive measure (the Iowa Gambling Task; IGT) and a novel task that simulated a real-life social situation (an online chatroom in which participants interacted with other men and women in sexually suggestive scenarios). Participants were exposed to either an acute psychosocial stressor or an equivalent control condition. Stressor-exposed participants were further characterized as high- or low-cortisol responders. Results confirmed that the experimental manipulation was effective. On the IGT, participants characterized as low-cortisol responders (as well as those in the Non-Stress group) made significantly riskier decisions than those characterized as high-cortisol responders. Similarly, in the online chatroom, participants characterized as low-cortisol responders (but not those characterized as high-cortisol responders) were, relative to those in the Non-Stress group, significantly more likely to make risky decisions. Together, these results suggest that at lower levels of cortisol both men and women tend to make riskier decisions in both economic and social spheres.

Safety on demand: Post-hypnotic suggestions of safety reduce neural signals of reward sensitivity with long-term beneficial effects

Increased reward sensitivity has been proposed as an important transdiagnostic feature for a series of disorders, including addictive behaviors. Earlier studies suggest that a positive affective state characterized by the feeling of safety could reduce an individual's reward sensitivity. A promising technique to establish a feeling of safety on demand is to utilize post-hypnotic suggestions. We hypothesized that the feeling of safety elicited by post-hypnotic suggestions reduces neural signals of reward sensitivity. To test our predictions, we hypnotized 24 highly suggestible participants, suggested them to feel safe and coupled this feeling of safety to a post-hypnotic trigger that reactivates the feeling of safety outside the hypnotic state. Participants then played a risk game both in a safety condition using the post-hypnotic safety trigger and in a control condition using a neutral trigger. Simultaneously, we recorded their EEG. Participants reported significantly higher ratings of safety in the safety condition compared to the control condition. Even several weeks after the main experimental session, the post-hypnotic safety trigger still elicited a significantly stronger feeling of safety compared to the control condition. Moreover, the Reward Positivity (RewP) was significantly reduced in the safety condition. As the RewP amplitude has been proposed as a psychophysiological marker for reward sensitivity, we conclude that the suggestion of safety by post-hypnotic suggestions turns participants into a quiescence motivational state that makes them less reward sensitive. Therefore, we discuss implications of the post-hypnotic safety trigger for the treatment of disorders associated with increased reward sensitivity such as addictive behaviors.

The impact of emotions on shopping behavior during epidemic. What a business can do to protect customers

The study investigated how the perception of in-shop COVID-19 contraction influences emotions in decision-making and how they further effect actions undertaken by consumers to control the situation within a store. Structural equation modeling was used to study the relationship between the risk of in-store infection, emotions and in-shop behavior, based on data retrieved from 914 questionnaires. Results showed, that the perceived risk of becoming infected in a store causes an increase in arousal and, at the same time, a decrease in perceived pleasure during shopping. The rise in arousal led to an increase in consumers taking actions to decrease their risk of contagion, while an increase in noticeable pleasure lowered interest of following recommendations for pandemic behavior. The findings imply that through changes regarding in-store atmosphere, stationary shops can provide consumers with a sense of urgency and awareness of infection risk so that they may do their shopping more efficiently.

The influence of fear on risk taking: a meta-analysis

A common finding in the study of emotion and decision making is the tendency for fear and anxiety to decrease risk taking. The current meta-analysis summarises the strength and variability of this effect in the extant empirical literature. Our analysis of 136 effect sizes, derived from 68 independent samples and 9,544 participants, included studies that experimentally manipulated fear or measured naturally varying levels of fear or anxiety in both clinical and non-clinical samples, and studies measuring risky decision making and risk estimation. A multilevel random effects model estimated a small to moderate average effect size (r = 0.22), such that fear was related to decreased risky decision making and increased risk estimation. There was also high heterogeneity in the effect sizes. Moderator analyses showed that effect sizes were greater when risk tasks used tangible (e.g. monetary) outcomes and when studies used clinically anxious participants. However, there also remained considerable variability in effect sizes, the sources of which remain unknown. We posit several potential factors that may contribute to observed variability in this effect for future study, including factors concerning both the nature of fear experience and the risk taking context.

Feel Safe and Money is Less Important! Hypnotic Suggestions of Safety Decrease Brain Responses to Monetary Rewards in a Risk Game

When a stimulus is important, the corresponding brain responses increase, especially the P300 brain response. This is true for all kinds of important stimuli, also monetary rewards. In our study, we developed a hypnotic suggestion to reduce the subjective importance of monetary rewards. As successful suggestions do not contain negations, we suggested participants to feel safe during hypnosis instead of suggesting that money is not important anymore. We predicted lower P300 amplitudes when participants feel safe during hypnosis. We tested 24 highly suggestible participants playing a risk game in 2 conditions with monetary rewards while we measured their EEG brain responses. In the safety condition, we induced a hypnotic state and suggested that participants feel safe. In the control condition, participants played the risk game without hypnosis. Here we show that participants felt significantly safer in the safety condition and showed significantly lower P300 amplitudes to monetary rewards. Risk behavior did not differ significantly between conditions. Our results are important for substance use disorders, as decreased P300 responses to substance-related stimuli are associated with less craving and better abstinence. Therefore, we conclude that suggestions to feel safe during hypnosis might work as a treatment for individuals with substance use disorders.

Vagal signaling and the somatic marker hypothesis: The effect of transcutaneous vagal nerve stimulation on delay discounting is modulated by positive mood

Controlling impulsivity and delaying gratifications are key features of effective self-control. Delay Discounting (DD) indexes the ability to delay rewards and previous research has shown that discounting is influenced by affective states such as mood. According to the Somatic Marker Hypothesis (SMH), afferent somatic signals, such as mood, are carried by the vagus and can influence decision making. In the current study, we employed transcutaneous vagus nerve stimulation (tVNS), a novel non-invasive brain stimulation technique that stimulates the auricular branch of the afferent vagus nerve (located in the outer ear), to assess its effects on decision impulsivity, while taking into account individuals' mood and resting-state HRV as a possible confounding factor. Employing a within-subjects cross-over design, 94 participants received active or sham tVNS while performing delay discounting in two separate sessions. As compared to sham, active tVNS increased discounting, but only for individuals reporting lower positive mood, regardless of the level of negative mood reported. We evidence that the effect of tVNS on reward discounting depends on the level of positive mood. This result suggests that positive mood state might be a proxy of task-relevant arousal, likely influencing the effectiveness of afferent vagal stimulation on self-control processes, as temporal discounting.

Alcohol misuse and traumatic brain injury: a review of the potential roles of dopaminergic dysfunction and physiological underarousal post-injury

Although many researchers have demonstrated an increase in alcohol use following traumatic brain injury (TBI), there is also a body of research indicating that alcohol misuse predisposes one to injury and precedes TBI. Accordingly, various mechanisms have been proposed (e.g., self-medication, dampened levels of arousal, dopaminergic dysfunction, etc.) and variable results have emerged. This paper reviews the empirical evidence, for and against, TBI as a risk factor for alcohol misuse. In particular, this paper focuses on the brain-behavior relationships involved and examines the roles of physiological underarousal and dopaminergic dysfunction in the development of alcohol misuse after injury. Alcohol misuse impedes community reintegration among TBI survivors and creates additional rehabilitative challenges. Thus, in order to inform and improve treatment outcomes among this vulnerable population, a deeper understanding of the neural mechanisms implicated is needed.

The impact of Yohimbine-induced arousal on facets of behavioural impulsivity

RATIONALE

State-dependent changes in physiological arousal may influence impulsive behaviours.

OBJECTIVES

To examine the relationship between arousal and impulsivity, we assessed the effects of yohimbine (an α₂-adrenergic receptor antagonist, which increases physiological arousal via noradrenaline release) on performance on established laboratory-based impulsivity measures in healthy volunteers.

METHODS

Forty-three participants received a single dose of either yohimbine hydrochloride or placebo before completing a battery of impulsivity measures. Blood pressure and heart rate were monitored throughout the study.

RESULTS

Participants in the yohimbine group showed higher blood pressure and better response inhibition in the Stop Signal Task, relative to the placebo group. Additionally, individual changes in blood pressure were associated with performance on Delay Discounting and Information Sampling tasks: raised blood pressure following drug ingestion was associated with more far-sighted decisions in the Delay Discounting Task (lower temporal impulsivity) yet reduced information gathering in the Information Sampling Task (increased reflection impulsivity).

CONCLUSIONS

These results support the notion that impulsive behaviour is dependent upon state physiological arousal; however, distinct facets of impulsivity are differentially affected by physiological changes.

Risk-Taking and Impulsivity: The Role of Mood States and Interoception

Objectives: The consequences of impulsive decisions and actions represent a major source of concern to the health and well-being of individuals and society. It is, therefore, crucial to understand the factors which contribute to impulsive behaviors. Here, we examined how personality traits of behavioral tendencies, interoceptive sensibility as well as transient mood states predict behavioral performance on impulsivity and risk-taking tasks.

Method: 574 (121 males; age 18–45) individuals completed self-report personality measures of impulsivity, reward sensitivity, punishment avoidance as well as interoceptive sensibility, undertook a mood assessment and performed a set of cognitive tasks: delay discounting (temporal impulsivity), probability discounting (risk-taking), and reflection impulsivity task. Data were interrogated using principal component analysis, correlations and regression analyses to test mutual relationships between personality traits, interoceptive sensibility, mood state and impulsive behaviors.

Results: We observed a clear separation of measures used, both trait and behavioral. Namely, sensation-seeking, reward sensitivity and probability discounting reflected risk-taking. These were separate from measures associated with impulsivity, both trait (negative and positive urgency, premeditation, perseverance) and behavioral (delayed discounting and reflection impulsivity). This separation was further highlighted by their relationship with the current emotional state: positive affect was associated with increased risk-taking tendencies and risky decision-making, while negative emotions were related to heightened impulsivity measures. Interoceptive sensibility was only associated with negative emotions component.

Conclusion: Our findings support the proposal that risk-taking and impulsivity represent distinct constructs that are differentially affected by current mood states. This novel insight enhances our understanding of impulsive behaviors.

Physiological underarousal as a mechanism of aggressive behavior in university athletes with a history of concussion

INTRODUCTION

Research has indicated that athletes who engage in high-risk athletic activities, such as football and hockey, have riskier personalities than their low-risk and nonathlete counterparts (Ahmadi et al., 2011, Procedia Soc Behav Sci, 30 and 247-251; Zuckerman, 1983, Biological bases of sensation seeking, impulsivity, and anxiety, Lawrence Erlbaum Assoc Inc.). For instance, increased sensation-seeking and aggression are common in high-risk athletes, rendering these individuals more likely to sustain a subsequent injury, such as concussion. Elevated levels of certain personality traits, including impulsivity and aggression, have also been observed after concussion (Goswami et al., 2016, Brain Struct Funct, 221 and 1911-1925). The purpose of this study therefore was to determine whether aggressive behavior in university athletes may be accounted for, in part, by a history of concussion, rather than exclusively athletic status.

METHODS

Using a quasi-experimental design, 66 university students (n = 18 nonathletes, n = 24 low-risk athletes, n = 24 high-risk athletes) with (n = 27) and without a history of concussion (n = 39) completed the Buss & Perry Aggression Questionnaire (BPAQ; Buss & Perry, , J Pers Soc Psychol, 63 and 452) and provided electrodermal activation (EDA) as an index of physiological arousal.

RESULTS

It was found that decreased physiological arousal among students with a history of concussion was associated with greater endorsement of physical aggression. Moreover, athletic status did not account for this pattern of aggression, as athletes and nonathletes did not differ in terms of self-reported aggressive tendencies.

CONCLUSIONS

Physiological compromise after concussive injury may act as an independent mechanism of aggressive behavior in athletes beyond factors, such as athletic status.

What Makes Us Feel Good or Bad

Abstract. Affective science calls for methods to induce mood in an engaging and ecologically valid way. We present a method employing a naturally occurring scenario that fits these criteria: a job interview. Participants got positive or negative feedback from a fictive expert to induce positive or negative mood. After mood induction, we assessed participants’ decision making behavior in the so-called information sampling task (IST). Results show that our mood induction successfully changed valence, dominance, and state self-esteem ratings, while there were no differences in arousal ratings. Decision making in the IST was not influenced by the induced mood. Effect sizes of mood induction were equally high for positive and negative mood concerning valence ratings (d = .8) with participants scoring high on self-control showing smaller mood induction effects. We conclude that our mood induction technique is an effective and natural way to induce mood in the laboratory, meeting current criteria of affective science.

The role of emotions and physiological arousal in modulating impulsive behaviour

Impulsivity received considerable attention in the context of drug misuse and certain neuropsychiatric conditions. Because of its great health and well-being importance, it is crucial to understand factors which modulate impulsive behaviour. As a growing body of literature indicates the role of emotional and physiological states in guiding our actions and decisions, we argue that current affective state and physiological arousal exert a significant influence on behavioural impulsivity. As 'impulsivity' is a heterogeneous concept, in this paper, we review key theories of the topic and summarise information about distinct impulsivity subtypes and their methods of assessment, pointing out to the differences between the various components of the construct. Moreover, we review existing literature on the relationship between emotional states, arousal and impulsive behaviour and suggest directions for future research.

Positive Arousal Increases Individuals' Preferences for Risk

Much is known about the effect of negative arousal on decision making, but little is known about the effect of positive arousal. In this study, we manipulated positive arousal and measured individual choices under risk using an incentivized task. Participants were randomly assigned to either a low arousal or a high arousal condition and asked to choose between pairs of two-outcome monetary lotteries with the same expected value but different risk in terms of outcome variance. The probability was set at 50% for each lottery. Participants in the high arousal group selected the riskier lottery more often and took more time to make choices than participants in the low arousal group. This finding shows that introducing a pleasant arousing cue as part of the decision context shifts an individual’s preferences toward the risky economic option and away from the safer one.

Cardiac Signals Are Independently Associated with Temporal Discounting and Time Perception

Cardiac signals reflect the function of the autonomic nervous system (ANS) and have previously been associated with a range of self-regulatory behaviors such as emotion regulation and memory recall. It is unknown whether cardiac signals may also be associated with self-regulation in the temporal domain, in particular impulsivity. We assessed both decision impulsivity (temporal discounting, TD) and time perception impulsivity (duration reproduction, DR) in 120 participants while they underwent electrocardiography in order to test whether cardiac signals were related to these two aspects of impulsivity. We found that over the entire period of task performance, individuals with higher heart rates had a tendency toward lower discount rates, supporting previous research that has associated sympathetic responses with decreased impulsivity. We also found that low-frequency components of heart rate variability (HRV) were associated with a less accurate perception of time, suggesting that time perception may be modulated by ANS function. Overall, these findings constitute preliminary evidence that autonomic function plays an important role in both decision impulsivity and time perception.

Prudence, Emotional State, Personality, and Cognitive Ability

We report an experiment to consider the emotional correlates of prudent decision making. In the experiment, we present subjects with lotteries and measure their emotional response with facial recognition software. They then make binary choices between risky lotteries that distinguish prudent from imprudent individuals. They also perform tasks to measure their cognitive ability and a number of personality characteristics. We find that a more negative emotional state correlates with greater prudence. Higher cognitive ability and less conscientiousness is also associated with greater prudence.

Fear of the unknown: One fear to rule them all?

The current review and synthesis was designed to provocatively develop and evaluate the proposition that "fear of the unknown may be a, or possibly the, fundamental fear" (Carleton, 2016) underlying anxiety and therein neuroticism. Identifying fundamental transdiagnostic elements is a priority for clinical theory and practice. Historical criteria for identifying fundamental components of anxiety are described and revised criteria are offered. The revised criteria are based on logical rhetorical arguments using a constituent reductionist postpositivist approach supported by the available empirical data. The revised criteria are then used to assess several fears posited as fundamental, including fear of the unknown. The review and synthesis concludes with brief recommendations for future theoretical discourse as well as clinical and non-clinical research.

The framing effect and skin conductance responses

Individuals often rely on simple heuristics when they face complex choice situations under uncertainty. Traditionally, it has been proposed that cognitive processes are the main driver to evaluate different choice options and to finally reach a decision. Growing evidence, however, highlights a strong interrelation between judgment and decision-making (JDM) on the one hand, and emotional processes on the other hand. This also seems to apply to judgmental heuristics, i.e., decision processes that are typically considered to be fast and intuitive. In this study, participants are exposed to different probabilities of receiving an unpleasant electric shock. Information about electric shock probabilities is either positively or negatively framed. Integrated skin conductance responses (ISCRs) while waiting for electric shock realization are used as an indicator for participants' emotional arousal. This measure is compared to objective probabilities. I find evidence for a relation between emotional body reactions measured by ISCRs and the framing effect. Under negative frames, participants show significantly higher ISCRs while waiting for an electric shock to be delivered than under positive frames. This result might contribute to a better understanding of the psychological processes underlying JDM. Further studies are necessary to reveal the causality underlying this finding, i.e., whether emotional processes influence JDM or vice versa.

Towards a biopsychological understanding of costly punishment: the role of basal cortisol

Recent findings have documented a negative relation of basal endogenous cortisol and aggression after a provocation (i.e., reactive aggression) in humans. We build on these findings and investigated the relation of endogenous cortisol and reactive aggression in a social dilemma situation, that is, costly punishment of individuals who did not appropriately contribute to a common group project. Specifically, we predicted that basal cortisol is negatively related to costly punishment of uncooperative individuals. In the present study, basal cortisol was assessed prior to a public goods game with the option to punish other group members. In line with previous research on reactive aggression and basal cortisol, we found that basal cortisol was indeed negatively related to costly punishment. The findings are important for understanding costly punishment because this tendency has been documented as a possible basis for the evolution of cooperation.