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CONTEXT: Human beings are highly social creatures who often touch each other during social interactions. Although the physiologic effects of touch are not understood fully, it appears to sustain social bonds and to increase cooperative behaviors. Oxytocin (OT) is a hormone known to facilitate social bonding, and touch may affect OT release. Previous studies seeking to relate massage and oxytocin in humans have been inconsistent in their findings. OBJECTIVES: This study examined the effect of massage on oxytocin and also measured its effect on other physiologic factors, including adrenocorticotropin hormone (ACTH), nitric oxide (NO), and beta-endorphin (BE). DESIGN: The research team advertised that the trial would study relaxation and assigned participants randomly to the intervention or the control group. A lab administrator assigned a random numeric code to participants to mask their identities. SETTING: The study took place at the University of California Los Angeles (UCLA), Los Angeles, CA. PARTICIPANTS: Ninety-five people from UCLA gave written informed consent for participation in the study, with the team paying them to participate. The intervention group included 65 participants and the control group 30 participants. INTERVENTION: For the intervention (massage) group, the research team drew participants' blood and followed the blood draw with 15 minutes of moderate-pressure massage of the upper back. The control (rest) group rested quietly for 15 minutes after the blood draw. A second blood draw followed for both groups. OUTCOME MEASURES: The research team assayed OT, ACTH, NO, and BE. The team used four survey instruments to examine the relationship between personality factors and the physiologic measures of interest. The team analyzed data using SPSS 15.0 for Windows. RESULTS: Massage was associated with an increase in OT and reductions in ACTH, NO, and BE. Comparing the effects of massage for the massage group with those for the rest group, the research team found significant differences between groups for changes in OT, ACTH, NO, and BE. CONCLUSIONS: This study is the first using a large sample of mixed gender that demonstrates that massage increases OT and decreases ACTH, NO, and BE. These findings may help explain the mechanisms through which social connections reduce morbidity and mortality. [ABSTRACT FROM AUTHOR]

Mental health professionals have relied primarily on clinical evaluations to identify in vivo pathology. As a result, mental health is largely reactive rather than proactive. In an effort to proactively assess mood, we collected continuous neurophysiologic data for ambulatory individuals 8-10 h a day at 1 Hz for 3 weeks ( N  = 24). Data were obtained using a commercial neuroscience platform (Immersion Neuroscience) that quantifies the neural value of social-emotional experiences. These data were related to self-reported mood and energy to assess their predictive accuracy. Statistical analyses quantified neurophysiologic troughs by the length and depth of social-emotional events with low values and neurophysiologic peaks as the complement. Participants in the study had an average of 2.25 (SD = 3.70, Min = 0, Max = 25) neurophysiologic troughs per day and 3.28 (SD = 3.97, Min = 0, Max = 25) peaks. The number of troughs and peaks predicted daily mood with 90% accuracy using least squares regressions and machine learning models. The analysis also showed that women were more prone to low mood compared to men. Our approach demonstrates that a simple count variable derived from a commercially-available platform is a viable way to assess low mood and low energy in populations vulnerable to mood disorders. In addition, peak Immersion events, which are mood-enhancing, may be an effective measure of thriving in adults., Competing Interests: The senior author (PJZ) is one of the founders of Immersion Neuroscience that was used in the data collection, but he had no influence on the analysis or interpretation of the findings. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Merritt and Zak.)

Introduction: Oral contraceptives (OCs) are primarily known for their effects on the reproductive system, but they can also impact the hypothalamic-pituitary-adrenal (HPA) axis. The present study aimed to compare plasma adrenocorticotropic hormone (ACTH) responses to the anticipatory stress of participating in a scientific experiment and venepuncture in OC users versus naturally cycling (NC) women, with a focus on variations throughout the menstrual cycle., Methods: We recruited 131 young women (average age 20.5) and obtained blood samples to measure plasma ACTH concentrations immediately after venepuncture and again after 15 min of group activities designed to facilitate interpersonal attachment and stress-buffering., Results: ACTH levels decreased in 70% of all participants throughout the group activities. A two-way repeated measures ANOVA highlighted a significant interaction between time and OC use, indicating differential changes in ACTH levels during social interaction between OC users and NC women. Further, the post-hoc analysis revealed that a period of stress-buffering group activities significantly decreased ACTH levels in NC women during menstrual and secretory phases, but not during the proliferative phase. In contrast, OC users did not display a decrease during group activities, regardless of the phase., Conclusion: This study underscores the influence of OC use on stress regulation, demonstrating that OCs not only modulate reproductive functions but also impact ACTH stress reactivity. Additionally, it emphasizes the importance of considering hormonal contraceptive use and menstrual cycle phases when assessing female stress responses., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Identifying hit songs is notoriously difficult. Traditionally, song elements have been measured from large databases to identify the lyrical aspects of hits. We took a different methodological approach, measuring neurophysiologic responses to a set of songs provided by a streaming music service that identified hits and flops. We compared several statistical approaches to examine the predictive accuracy of each technique. A linear statistical model using two neural measures identified hits with 69% accuracy. Then, we created a synthetic set data and applied ensemble machine learning to capture inherent non-linearities in neural data. This model classified hit songs with 97% accuracy. Applying machine learning to the neural response to 1st min of songs accurately classified hits 82% of the time showing that the brain rapidly identifies hit music. Our results demonstrate that applying machine learning to neural data can substantially increase classification accuracy for difficult to predict market outcomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Merritt, Gaffuri and Zak.)

Streaming services provide people with a seemingly infinite set of entertainment choices. This large set of options makes the decision to view alternative content or stop consuming content altogether compelling. Yet, nearly all experimental studies of the attributes of video content and their ability to influence behavior require that participants view stimuli in their entirety. The present study measured neurophysiologic responses while participants viewed videos with the option to stop viewing without penalty in order to identify signals that capture the neural value of content. A post-video behavioral choice was included to reduce the likelihood that measured neurophysiologic responses were noise rather than signal. We found that a measure derived from neurophysiologic Immersion predicted how long participants would watch a video. Further, the time spent watching a video increased the likelihood that it influenced behavior. The analysis indicates that the neurologic value one receives helps explain why people continue to watch videos and why they are influenced by them., Competing Interests: The senior author PZ is one of the founders of Immersion Neuroscience that was used in the data collection, but he had no influence on the analysis or interpretation of the findings. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lin, Narender and Zak.)

The elderly have an elevated risk of clinical depression because of isolation from family and friends and a reticence to report their emotional states. The present study explored whether data from a commercial neuroscience platform could predict low mood and low energy in members of a retirement community. Neurophysiologic data were collected continuously for three weeks at 1Hz and averaged into hourly and daily measures, while mood and energy were captured with self-reports. Two neurophysiologic measures averaged over a day predicted low mood and low energy with 68% and 75% accuracy. Principal components analysis showed that neurologic variables were statistically associated with mood and energy two days in advance. Applying machine learning to hourly data classified low mood and low energy with 99% and 98% accuracy. Two-day lagged hourly neurophysiologic data predicted low mood and low energy with 98% and 96% accuracy. This study demonstrates that continuous measurement of neurophysiologic variables may be an effective way to reduce the incidence of mood disorders in vulnerable people by identifying when interventions are needed.

Helping behaviors and life satisfaction generally increase after middle-age. Identifying the neural substrates of prosocial behaviors in older adults may offer additional insights into these changes over the lifespan. The present study examines the endogenous release of the neuromodulator oxytocin (OT) in participants aged 18-99 and its relationship to prosocial behaviors. OT has been shown to influence trust, altruism, charity, and generosity, yet the effect of age on OT release has not been well-established. Blood samples before and after a video stimulus were obtained from 103 participants in order to examine the impact of OT on prosocial behaviors. We found that OT release following a social prime increased with age ( r = 0.49, p = 0.001) and that OT moderated the relationship between age and donations to charity. We tested for robustness by examining three additional prosocial behaviors, money and goods donated to charity during the past year and social-sector volunteering. OT moderated the impact of age on all three prosocial behaviors ( ps < 0.05). The analysis also showed that participants' change in OT was positively associated with satisfaction with life ( p = 0.04), empathic concern ( p = 0.015), dispositional gratitude ( p = 0.019), and religious commitment ( p = 0.001). Our findings indicate that the neural chemistry that helps sustain social relationships and live a fulfilled life appear to strengthen with age., Competing Interests: BC was employed by TripActions. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zak, Curry, Owen and Barraza.)

Trust is risky. The mere perception of strategically deceptive behavior that disguises intent or conveys unreliable information can inhibit cooperation. As gregariously social creatures, human beings would have evolved physiologic mechanisms to identify likely defectors in cooperative tasks, though these mechanisms may not cross into conscious awareness. We examined trust and trustworthiness in an ecological valid manner by (i) studying working-age adults, (ii) who make decisions with meaningful stakes, and (iii) permitting participants to discuss their intentions face-to-face prior to making private decisions. In order to identify why people fulfill or renege on their commitments, we measured neurophysiologic responses in blood and with electrodermal activity while participants interacted. Participants (mean age 32) made decisions in a trust game in which they could earn up to $530. Nearly all interactions produced promises to cooperate, although first decision-makers in the trust game reneged on 30.7% of their promises while second decision-makers reneged on 28%. First decision-makers who reneged on a promise had elevated physiologic stress using two measures (the change in adrenocorticotropin hormone and the change in skin conductance levels) during pre-decision communication compared to those who fulfilled their promises and had increased negative affect after their decisions. Neurophysiologic reactivity predicted who would cooperate or defect with 86% accuracy. While self-serving behavior is not rare, those who exhibit it are stressed and unhappy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zak, Barraza, Hu, Zahedzadeh and Murray.)

Sexual sadists derive pleasure from humiliation, domination and infliction of pain on victims. They display increased penile arousal and activation of brain regions involved in sexual arousal and emotional states when viewing stimuli depicting individuals in physical distress. Neuroactive hormones modulate these regions, but it is unknown if sexual sadists also have endocrine responses to depictions of individuals in distress. The present study examined endocrine responses, elicited by viewing a video depicting an individual in extreme emotional distress, in incarcerated adult male sexual offenders (n = 23) with varying levels of sadistic traits. Sadism, was measured by the Severe Sexual Sadism Scale (SeSaS). Testosterone (T), adrenocorticotropic hormone (ACTH), and oxytocin (OT) were assayed before and after participants watched a video depicting an individual in emotional distress. T responses to the video were significantly and positively associated with SeSaS scores. There were no significant associations between sexual sadism and OT or ACTH. Our findings provide physiological evidence of atypical processing of distress cues in sadism consistent with the role of testosterone in sexual arousal and aggressive behaviors. These findings have implications for the evaluation and treatment of sexual sadists., Competing Interests: Conflict of interest statement: On behalf of all authors, the corresponding author states that there is no conflict of interest.

Humans express loyalty to consumer brands much like they do in human relationships. The neuroactive chemical oxytocin is an important biological substrate of human attachment and this study tested whether consumer-brand relationships can be influenced by oxytocin administration. We present a mathematical model of brand attachment that generates empirically-testable hypotheses. The model is tested by administering synthetic oxytocin or placebo to male and female participants (N = 77) who received information about brands and had an opportunity to purchase branded products. We focused on two brand personality dimensions: warmth and competence. Oxytocin increased perceptions of brand competence but not brand warmth relative to placebo. We also found that participants were willing to pay more for branded products through its effect on brand competence. When writing about one's favorite brands, oxytocin enhanced the use of positive emotional language as well as words related to family and friends. These findings provide preliminary evidence that consumers build relationships with brands using the biological mechanisms that evolved to form human attachments., Competing Interests: The authors have declared that no competing interests exist.

Human behavior lies somewhere between purely self-interested homo economicus and socially-motivated homo reciprocans. The factors that cause people to choose self-interest over costly cooperation can provide insights into human nature and are essential when designing institutions and policies that are meant to influence behavior. Alcohol consumption can shed light on the inflection point between selfish and selfless because it is commonly consumed and has global effects on the brain. The present study administered alcohol or placebo (N = 128), titrated to sex and weight, to examine its effect on cooperation in a standard task in experimental economics, the public goods game (PGG). Alcohol, compared to placebo, doubled the number of free-riders who contributed nothing to the public good and reduced average PGG contributions by 32% (p = .005). This generated 64% higher average profits in the PGG for those who consumed alcohol. The degree of intoxication, measured by blood alcohol concentration, linearly reduced PGG contributions (r = -0.18, p = .05). The reduction in cooperation was traced to a deterioration in mood and an increase in physiologic stress as measured by adrenocorticotropic hormone. Our findings indicate that moderate alcohol consumption inhibits the motivation to cooperate and that homo economicus is stressed and unhappy., Competing Interests: The authors have declared that no competing interests exist.

This paper reports findings from a nationally representative sample of working adults to quantify how a culture trust improves business performance. Analysis of the national sample showed that organizational trust and alignment with the company's purpose are associated with higher employee incomes, longer job tenure, greater job satisfaction, less chronic stress, improved satisfaction with life, and higher productivity. Employees working the highest quartile of organizational trust had average incomes 10.3% higher those working in the middle quartile of trust ( p = 0.000) indicating that trust increases productivity. In order to demonstrate the causal effect of trust on business performance, we created an intervention to increase organizational trust in a division facing high job turnover at a large online retailer. The intervention increased organizational trust by 6% and this improved job retention by 1%. These studies show that management practices that increase organizational trust have salubrious effects on business performance., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Johannsen and Zak.)

Background: Neonatal male circumcision is a painful skin-breaking procedure that may affect infant physiological and behavioral stress responses as well as mother-infant interaction. Due to the plasticity of the developing nociceptive system, neonatal pain might carry long-term consequences on adult behavior. In this study, we examined whether infant male circumcision is associated with long-term psychological effects on adult socio-affective processing., Methods: We recruited 408 men circumcised within the first month of life and 211 non-circumcised men and measured socio-affective behaviors and stress via a battery of validated psychometric scales., Results: Early-circumcised men reported lower attachment security and lower emotional stability while no differences in empathy or trust were found. Early circumcision was also associated with stronger sexual drive and less restricted socio-sexuality along with higher perceived stress and sensation seeking., Limitations: This is a cross-sectional study relying on self-reported measures from a US population., Conclusions: Our findings resonate with the existing literature suggesting links between altered emotional processing in circumcised men and neonatal stress. Consistent with longitudinal studies on infant attachment, early circumcision might have an impact on adult socio-affective traits or behavior., Competing Interests: The authors declare no conflict of interest., (© 2020 The Author(s).)

Oral contraception (OC) is used by approximately fifty-five million women in the USA alone and is listed as an essential medicine by the World Health Organisation. Altered mood is a common reason for OC cessation. Here we investigate the effects of OC on hormones that are linked to mood. We obtained blood samples from 185 young women (average age 21.2) in two cohorts and tested the effects of OC on plasma levels of oxytocin, adrenocorticotropic hormone (ACTH), estradiol, progesterone and testosterone. We related plasma hormone levels with self-reported measures of mood, well-being and depression. OC-users in both cohorts showed elevated basal oxytocin, lower ACTH, estradiol, progesterone and testosterone compared with non-OC users. Satisfaction With Life Score (SWLS) was higher in OC -users compared to non-OC users, with no differences in the Beck Depression Score (BDI) and Positive And Negative Affect Schedule (PANES). In conclusion, our data show alterations in hormone levels and SWLS in response to OC.

Employees have been given increasing autonomy to work from home, from virtual offices, and during travel. Understanding why autonomy affects work behaviors has relied to date on self-reported data in which employees may consciously or unconsciously misattribute their own causal actions. We designed a neuroscience experiment to investigate the mechanisms through which greater autonomy affects individual and team performance and if this had an effect on mood. Participants ( N = 100) were shown a three-min video that described the productivity impact of greater autonomy at work (treatment) or the productivity benefits of work-flow management software. Electrodermal responses were captured to measure physiologic effort and were related to the video stimuli, productivity, and mood. The treatment group had a 5.2% ( p = 0.047) greater average productivity and 31% ( p = 0.000) higher positive affect after the video than the control group average. Productivity was directly related to the physiologic effort put into the task for both the treatment and control groups, but the video prime did not increase effort compared to the control. The impact of physiologic effort on productivity continued to hold when controlling for participants' intrinsic motivation. We also found that individual productivity was associated with an increase in positive affect, while group productivity increased positive affect only for those in the treatment group. Our findings indicate that increased perceived autonomy can significantly improve individual and group productivity and that this can have a salubrious impact on mood, but the neurologic mechanism through which this occurs remains to be identified., (Copyright © 2020 Johannsen and Zak.)

Objective: Patients with psychogenic non-epileptic seizures (PNES) may present with convulsive events that are not accompanied by epileptiform brain activity. Video-electroencephalography (EEG) monitoring is the gold standard for diagnosis, yet not all patients experience convulsive episodes during video-EEG sessions. Hence, we aimed to construct a predictive model in order to detect PNES from serum hormone levels, detached from an evaluation of patients' convulsive episodes., Methods: Fifteen female patients with PNES and 60 healthy female controls participated in the study, providing blood samples for hormone analysis. A binomial logistic regression model and the leave-one-out cross-validation were employed., Results: We found that levels of neuropeptide Y and adrenocorticotropic hormone were the optimal combination of predictors, with over 90% accuracy (area under the curve=0.980)., Conclusions: The ability to diagnose PNES irrespective of convulsive events would represent an important step considering its feasibility and affordability in daily clinical practice.

Objective: The present study explores the relationship between neuroactive hormones and religious commitment. We hypothesised that religious commitment is mediated by neuropeptide Y and oxytocin. These neurohormones have a well-established role in general well-being, anxiety regulation, stress-resilience, social affiliation and spirituality., Methods: Sixty healthy women (median age 21) participated in the study and completed the Religious Commitment Inventory and other psychometric surveys. Blood was sampled from each participant and serum levels of neuropeptide Y were measured using radioimmunoassay. Oxytocin, stress and sex hormones were measured using enzyme-linked immunosorbent assay. Correlations were tested using non-parametric statistical methods., Results: We found a positive correlation between serum neuropeptide Y levels and religious commitment, but not between oxytocin and religious commitment., Conclusions: The present study provides preliminary evidence that neuropeptide Y is a biological correlate of religious commitment.

Oxytocin (OT) has been shown to facilitate trust, empathy and other prosocial behaviors. At the same time, there is evidence that exogenous OT infusion may not result in prosocial behaviors in all contexts, increasing in-group biases in a number of studies. The current investigation seeks to resolve this inconsistency by examining if endogenous OT release is associated with in-group bias. We studied a large group of participants ( N = 399) in existing groups and randomly formed groups. Participants provided two blood samples to measure the change in OT after a group salience task and then made computer-mediated monetary transfer decisions to in-group and out-group members. Our results show that participants with an increase in endogenous OT showed no bias in monetary offers in the ultimatum game (UG) to out-group members compared to in-groups. There was also no bias in accepting UG offers, though in-group bias persisted for a unilateral monetary transfer. Our analysis shows that the strength of identification with one's group diminished the effects that an increase in OT had on reducing bias, but bias only recurred when group identification reached 87% of its maximum value. Our results indicate that the endogenous OT system appears to reduce in-group bias in some contexts, particularly those that require perspective-taking.

Psychogenic non-epileptic seizures (PNES) is a conversion disorder that reflects underlying psychological distress. Female patients with PNES often present with a history of prolonged stressors, especially sexual abuse. In the current study, we studied the relationship between neuropeptide Y (NPY) and PNES symptoms in women with a history of sexual abuse. NPY has been associated with resilience to stress and we hypothesized that low levels would increase the extent and severity of PNES symptoms in this patient population. Serum levels of NPY, and related hormones were measured in fifteen female PNES patients and sixty female controls. PNES patients reported more severe abuse histories, feeling of abandonment, and decreased perception of quality of life than controls. Importantly, they also had lower NPY levels. Our analysis indicates that low levels of NPY in PNES may confer greater vulnerability to exhibit seizure-like symptoms and lower quality of life.

Buddhism shares with science the task of examining the mind empirically. But Buddhism has pursued, for two millennia, direct investigation of the mind through penetrating introspection. Neuroscience, on the other hand, relies on third-person knowledge in the form of scientific observation. In the book that is the subject of this review, two friends, one a Buddhist monk trained as a molecular biologist, and the other, a distinguished neuroscientist, offer their perspectives on the mind, the self, consciousness, the unconscious, free will, epistemology, meditation, and neuroplasticity .

Emotionally laden narratives are often used as persuasive appeals by charitable organizations. Physiological responses to a narrative may explain why some people respond to an appeal while others do not. In this study we tested whether autonomic and hormonal activity during a narrative predict subsequent narrative influence via charitable giving. Participants viewed a brief story of a father's experience with his 2-year-old son who has terminal cancer. After the story, participants were presented with an opportunity to donate some of their study earnings to a related charity. Measures derived from cardiac and electrodermal activity, including HF-HRV, significantly predicted donor status. Time-series GARCH models of physiology during the narrative further differentiated donors from non-donors. Moreover, cardiac activity and experienced concern were found to covary from moment-to-moment across the narrative. Our findings indicate that the physiological response to a stimulus, herein a narrative, can predict influence as indexed by stimulus-related behavior., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This essay introduces a neurologically-informed mathematical model of collective action (CA) that reveals the role for empathy and distress in motivating costly helping behaviors. We report three direct tests of model with a key focus on the neuropeptide oxytocin as well as a variety of indirect tests. These studies, from our lab and other researchers, show support for the model. Our findings indicate that empathic concern, via the brain's release of oxytocin, is a trigger for CA. We discuss the implications from this model for our understanding why human beings engage in costly CA.

The neuropeptide oxytocin (OT) modulates functioning of the hypothalamic-pituitary-adrenal (HPA) axis and regulates a range of social processes. Clinical studies have used intranasal OT administration to treat symptoms arising from a number of psychiatric disorders including autism, schizophrenia, and depression. Most of this research, however, has been based on single dose treatments of OT in younger adult populations. The present study examined the impact on the health and psychological well-being of a 10-day OT administration in an older adult population. Residentially housed older adults (N = 41, mean age of 80) were enrolled in a randomized, double-blind, placebo-controlled study. Participants received 40 IU intranasal OT or placebo for 10 consecutive days. No changes in mood or cardiovascular states were observed across the 10-day period. Repeated-measures ANOVAs showed that dispositional gratitude improved for the OT infused participants, although gratitude declined for placebo controls over the 10 days (p = .015). Those in the OT condition did not report a decline in physical functioning over time as was observed in the placebo condition (p = .05), and also reported less fatigue compared with controls (p = .03). No significant adverse events were reported throughout the entirety of the study, indicating that OT can be safely used with older adults.

This paper presents a neurophysiologic model of effective public service advertisements (PSAs) and reports two experiments that test the model. In Experiment 1, we show that after watching 16 PSAs participants who received oxytocin, compared to those given a placebo, donated to 57% more causes, donated 56% more money, and reported 17% greater concern for those in the ads. In Experiment 2, we measured adrenocorticotropin hormone (ACTH) and oxytocin levels in blood before and after participants watched a PSA. As predicted by the model, donations occurred when participants had increases in both ACTH and oxytocin. Our results indicate that PSAs with social content that cause OT release will be more effective than those that do not. Our results also explain why some individuals do not respond to PSAs.

Background: Generalized Social Anxiety Disorder (GSAD) is characterized by excessive fear and avoidance of several types of social and performance situations. The pathophysiology is not well understood, but research in animals and humans has provided evidence that oxytocin helps regulate normal social affiliative behavior. Previous work in healthy male subjects demonstrated a rise in plasma oxytocin after receiving a high trust signal. To examine the oxytocin system in GSAD, we measured plasma oxytocin in GSAD patients and controls, before and after the social "Trust Game," a neuroeconomic test examining trust behavior and reaction to trust using real monetary incentives., Methods: Thirty-nine subjects with GSAD and 28 healthy controls provided three blood samples for oxytocin measurement before the Trust Game, and one sample after the game. Plasma estradiol was also measured at baseline. The Trust Game protocol version prioritized the sending of a signal of high cooperation and trust to all participants. All analyses controlled for gender and estradiol levels., Results: Mean oxytocin levels post-Trust Game (P = .025), and overall (area under the curve, P = .011) were lower in GSADpatients compared to controls, after controlling for sex and estradiol. There was no significant change in oxytocin levels after the game in either group., Conclusions: We report low plasma oxytocin levels in patients with GSAD during a prosocial laboratory task paradigm. Additional research will be important to further examine the relationship between oxytocin and social behavior in GSAD., (© 2012 Wiley Periodicals, Inc.)

What determines success on Wall Street? This study examined if genes affecting dopamine levels of professional traders were associated with their career tenure. Sixty professional Wall Street traders were genotyped and compared to a control group who did not trade stocks. We found that distinct alleles of the dopamine receptor 4 promoter (DRD4P) and catecholamine-O-methyltransferase (COMT) that affect synaptic dopamine were predominant in traders. These alleles are associated with moderate, rather than very high or very low, levels of synaptic dopamine. The activity of these alleles correlated positively with years spent trading stocks on Wall Street. Differences in personality and trading behavior were also correlated with allelic variants. This evidence suggests there may be a genetic basis for the traits that make one a successful trader.

This study examined if the prosocial effects of oxytocin (OT) extend from individuals to a generalized other who is in need. Participants played a series of economic games to earn money and were presented with an opportunity to donate a portion of their earnings to charity. OT did not significantly increase the decision to donate, but among the 36% of participants who did donate, people infused with OT were found to donate 48% more to charity than those given a placebo. The amount of money earned in the experiment had no effect on whether or not a donation was made or the size of a donation. This is the first study showing that OT increases generosity in unilateral exchanges directed toward philanthropic social institutions, as opposed to immediate benefits directed at individuals or groups., (Copyright © 2011 Elsevier Inc. All rights reserved.)

How do human beings decide when to be selfish or selfless? In this study, we gave testosterone to 25 men to establish its impact on prosocial behaviors in a double-blind within-subjects design. We also confirmed participants' testosterone levels before and after treatment through blood draws. Using the Ultimatum Game from behavioral economics, we find that men with artificially raised T, compared to themselves on placebo, were 27% less generous towards strangers with money they controlled (95% CI placebo: (1.70, 2.72); 95% CI T: (.98, 2.30)). This effect scales with a man's level of total-, free-, and dihydro-testosterone (DHT). Men in the lowest decile of DHT were 560% more generous than men in the highest decile of DHT. We also found that men with elevated testosterone were more likely to use their own money punish those who were ungenerous toward them. Our results continue to hold after controlling for altruism. We conclude that elevated testosterone causes men to behave antisocially.

Empathy is related to a variety of prosocial behaviors, but the brain mechanisms producing the experience of empathy have not been fully characterized. This study investigated whether the experience of empathy raises oxytocin levels and affects subsequent generosity toward strangers. Short video clips of an emotional scene and an unemotional scene were used as stimuli. Participants rated the emotions they experienced and then played a $40 ultimatum game to gauge their generosity. We found that empathy was associated with a 47% increase in oxytocin from baseline. We also found the empathy-oxytocin response was stronger in women than in men. Higher levels of empathy were also associated with more generous monetary offers toward strangers in the ultimatum game. Our findings provide the first evidence that oxytocin is a physiologic signature for empathy and that empathy mediates generosity.

Oxytocin is a neuropeptide recently associated with social behavior in animals and humans, but the study of its function in populations with social deficits such as autism, schizophrenia, and social anxiety disorder has only recently begun. We measured plasma oxytocin in 24 patients with Generalized Social Anxiety Disorder (GSAD) and 22 healthy controls using an enzyme-linked immunosorbent assay. There were no significant differences in oxytocin level (pg/mL) between patients (M=163.0, SD=109.4) and controls (M=145.0, SD=52.9, z=0.21, P=0.8). Within the GSAD sample, however, higher social anxiety symptom severity adjusted for age and gender was associated with higher oxytocin level (R2=0.21, beta=0.014, SE=0.006, t=2.18, P=0.04). In addition, dissatisfaction with social relationships was associated with higher oxytocin levels (R2=0.18, beta=-0.20, SE=0.10, t=-2.01, P=0.05). Our data provide preliminary support for a link between social anxiety severity and plasma oxytocin. These findings may suggest a possible role for oxytocin as a facilitator of social behavior, an effect which may not be fully utilized in individuals with severe social anxiety.

Human beings routinely help strangers at costs to themselves. Sometimes the help offered is generous-offering more than the other expects. The proximate mechanisms supporting generosity are not well-understood, but several lines of research suggest a role for empathy. In this study, participants were infused with 40 IU oxytocin (OT) or placebo and engaged in a blinded, one-shot decision on how to split a sum of money with a stranger that could be rejected. Those on OT were 80% more generous than those given a placebo. OT had no effect on a unilateral monetary transfer task dissociating generosity from altruism. OT and altruism together predicted almost half the interpersonal variation in generosity. Notably, OT had twofold larger impact on generosity compared to altruism. This indicates that generosity is associated with both altruism as well as an emotional identification with another person.

Social attachment is vital for human health and welfare. Recent experimental evidence in humans has identified the role of neuroactive hormones, especially the peptide oxytocin, in mediating trusting behaviors. Herein, we test if the endocrinological basis for trust between humans scales up to the country level. Trust pervades nearly every aspect of our daily lives, yet survey data on trust show substantial variation across countries. Using 31 measures of biological, social, and environmental factors associated with hormone levels for a sample of 41 countries, we find that two classes of factors are related to trust: consumption of plant-based estrogens (phytoestrogens), and the presence of environmental conditions that include measures of estrogen-like molecules. Our findings provide preliminary evidence that interpersonal trust at the country level may be related to the intake of neuroactive hormones.

Human beings exhibit substantial interpersonal trust-even with strangers. The neuroactive hormone oxytocin facilitates social recognition in animals, and we examine if oxytocin is related to trustworthiness between humans. This paper reports the results of an experiment to test this hypothesis, where trust and trustworthiness are measured using the sequential anonymous "trust game" with monetary payoffs. We find that oxytocin levels are higher in subjects who receive a monetary transfer that reflects an intention of trust relative to an unintentional monetary transfer of the same amount. In addition, higher oxytocin levels are associated with trustworthy behavior (the reciprocation of trust). Absent intentionality, both the oxytocin and behavioral responses are extinguished. We conclude that perceptions of intentions of trust affect levels of circulating oxytocin.

Trust pervades human societies. Trust is indispensable in friendship, love, families and organizations, and plays a key role in economic exchange and politics. In the absence of trust among trading partners, market transactions break down. In the absence of trust in a country's institutions and leaders, political legitimacy breaks down. Much recent evidence indicates that trust contributes to economic, political and social success. Little is known, however, about the biological basis of trust among humans. Here we show that intranasal administration of oxytocin, a neuropeptide that plays a key role in social attachment and affiliation in non-human mammals, causes a substantial increase in trust among humans, thereby greatly increasing the benefits from social interactions. We also show that the effect of oxytocin on trust is not due to a general increase in the readiness to bear risks. On the contrary, oxytocin specifically affects an individual's willingness to accept social risks arising through interpersonal interactions. These results concur with animal research suggesting an essential role for oxytocin as a biological basis of prosocial approach behaviour.

This is the first report that endogenous oxytocin in humans is related to social behaviors, which is consistent with a large animal literature. Subjects are put into a social dilemma in which absent communication, cooperative behavior can benefit both parties randomly assigned to a dyad. The dilemma arises because one participant must make a monetary sacrifice to signal the degree of trust in the other before the other's behavioral response is known. We show that receipt of a signal of trust is associated with a higher level of peripheral oxytocin than that in subjects receiving a random monetary transfer of the same average amount. Oxytocin levels were also related to trustworthy behavior (sharing a greater proportion of the monetary gains). We conclude that oxytocin may be part of the human physiology that motivates cooperation.

This paper introduces an emerging transdisciplinary field known as neuroeconomics. Neuroeconomics uses neuroscientific measurement techniques to investigate how decisions are made. First, I present a basic overview of neuroanatomy and explain how brain activity is measured. I then survey findings from the neuroeconomics literature on acquiring rewards and avoiding losses, learning, choice under risk and ambiguity, delay of gratification, the role of emotions in decision-making, strategic decisions and social decisions. I conclude by identifying new directions that neuroeconomics is taking, including applications to public policy and law.

Proper patient selection is the key to successful surgical management. The presence of the appropriate symptoms, signs and imaging findings--along with the individual psychologic and socioeconomic factors--play a significant role in the selection process. Patient education is important so that the patient's expectations from surgery are aligned with the surgeon's expectations. When the patient has been properly selected, and there has been adherence to the decision-making principles, along with meticulous surgical technique, good outcomes can be expected with surgical management of patients with spinal stenosis.

Seventy-eight posterior transfers of the adductors of the hip in forty-two children who has spastic cerebral palsy were reviewed an average of 5.7 years after the operation (range, two to 14.6 years). The results were assessed on the basis of the patient's ability to walk, the range of motion of the affected hip or hips, and the radiographic measurements. In 88 per cent of the patients, the transfer was successful in improving or maintaining abduction, extension, functional walking, and stability of the hip. The failures were all in patients who were unable to walk and who had spastic quadriplegia. Tenotomy of the iliopsoas tendon at the time of the transfer procedure resulted in an improved range of motion of the hip.