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Oxytocin is associated with human trustworthiness
Abstract
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.
... Over the past few decades, researchers have begun to investigate whether oxytocin plays a crucial role in psychology outside these domains. In humans, experimental evidence suggests that oxytocin also promotes trust (i.e., how much trust people place in strangers) and reciprocity (i.e., how much people reciprocally cooperate when trusted) toward others [3][4][5]. For instance, experimental studies examining the effects of oxytocin administration demonstrated that, compared to placebo controls, those who were administered oxytocin became more trusting: They entrusted more money to strangers [6] and judged unfamiliar others as more trustworthy [7]. ...
... However, recent replication attempts have been unsuccessful in validating the trustenhancing effect of oxytocin. A meta-analysis of oxytocin administration experiments failed to show a robust effect of oxytocin on trust [9], and endogenous oxytocin levels were shown to have no association with behavioral or attitudinal trust [5,10,11]. Similarly, there has been limited evidence on whether oxytocin is associated with reciprocal behaviors [5,8,12]. ...
... A meta-analysis of oxytocin administration experiments failed to show a robust effect of oxytocin on trust [9], and endogenous oxytocin levels were shown to have no association with behavioral or attitudinal trust [5,10,11]. Similarly, there has been limited evidence on whether oxytocin is associated with reciprocal behaviors [5,8,12]. Therefore, the current literature requires researchers to carefully replicate and re-examine the previously reported associations between oxytocin and trust, as well as reciprocity. ...
Oxytocin has been proposed to regulate human trust. Previous experiments supported this claim by demonstrating that exogenous and endogenous oxytocin is associated with trust (how much trust people place in strangers) and reciprocity (how much people reciprocate when trusted). However, recent replication attempts have been unsuccessful in demonstrating the trust-enhancing effect of oxytocin, and there is limited evidence on whether oxytocin is associated with reciprocity. This study aimed to replicate the previously found nonlinear relationships between the endogenous oxytocin concentration and both trust and reciprocity by utilizing a monetarily incentivized trust game. In a college sample, we found that salivary oxytocin levels showed (i) an inverted U-shaped relationship with trust in men and (ii) a U-shaped relationship with reciprocity in women. The current results confirm the previous finding that endogenous oxytocin levels have nonlinear relationships with trust and reciprocity. Further research on the role of oxytocin secretion in trust and reciprocity is warranted.
... For example, the brain regions that support other-regarding preferences are relatively underdeveloped in adolescents (van den Bos et al., 2011). Moneysharing tasks that seek to measure cooperative behaviors, such as the "trust game" (Berg et al., 1995;Zak et al., 2004Zak et al., , 2005b are sensitive to framing effects (Burnham et al., 2000;Cronk, 2007), culture (Fershtman and Gneezy, 2001), communication (Buchan et al., 2006), intentions and beliefs (Croson, 2000;McCabe et al., 2003), and show gender differences (Buchan et al., 2008). When college students enter a lab for an experiment, they have knowledge of the cohort with whom they will interact that affects their behavior (Sutter and Kocher, 2007). ...
... ACTH was measured before and after the 2-min communication by drawing blood from an intravenous catheter into an 8ml EDTAcoated whole blood tube using a Vacutainer R . Once the blood was drawn, samples were immediately placed on ice and then spun in a refrigerated centrifuge at 4C for 12 min at 1,500 RPM following our previous protocol (Zak et al., 2005b). Blood serum and plasma were separated into 2 ml Fisher brand microtubes and immediately frozen on dry ice. ...
... DM2s do not appear to know in advance that they will renege on their promises to cooperate since they lack the stress response during the interaction period. Most studies support DM2 responses as being reactive after observing the DM1 transfer rather than planned (Zak et al., 2004(Zak et al., , 2005bMüller and Schwieren, 2020). Nevertheless, when DM2s renege they still experience negative affect similar to DM1s suggesting they know they are committing a norm violation. ...
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.
... Moreover, Declerck et al. [8] failed to replicate the findings of a previous study by Kosfeld et al. [5]. Regarding endogenous oxytocin, some studies [10,11] found no association between plasma oxytocin levels and trust. Taken together, based on exogenous and endogenous studies, oxytocin may not be directly associated with trust. ...
... This investigation may help scientists better understand the association between the salivary oxytocin level and attitudinal trust. Furthermore, we suggest that the salivary oxytocin level can be used as a biomarker for human prosociality and that examining the connection between salivary oxytocin and additional prosocial behaviors (e.g., reciprocity, cooperation) that are also associated with oxytocin is necessary [11,55]. ...
Studies on the association between trust and oxytocin, a neuropeptide of the central nervous system, have not reached a consensus, thereby challenging the possibility of a direct association between the two. However, previous studies have not examined how oxytocin is correlated with trust, based on its categorization into different factors in the field of social science. For instance, based on Yamagishi’s trust theory, trust can be categorized into two factors: general trust and caution. General trust refers to beliefs about the trustworthiness of others, whereas caution refers to the belief that caution is needed when dealing with high social uncertainty. In this study, to examine the relationship between these two factors and oxytocin, we analyzed data of 197 adults (men = 98, women = 99; mean age = 41.7 years; standard deviation for age = 10.4 years) and examined the relationships between these two factors of trust and endogenous salivary oxytocin levels. We found that oxytocin was positively correlated with caution rather than with general trust thereby suggesting that oxytocin plays a role in regulating caution rather than general trust among the components of trust. The present study demonstrated that salivary oxytocin level can act as a biomarker that partially predicts one’s trust, especially as reflected by caution.
... The biology of attachment has been informed by techniques to measure the brain's release of, and to pharmacologically manipulate, the neurochemical oxytocin (OT) in human. The brain releases OT after positive social interactions that undergird attachment and facilitates trustworthiness [24,25], donations to charity [26], and eliminates out-group biases [27]. Administration of exogenous OT increases trust in strangers [28], generosity [29], charity [30], improves the ability to understand others [31,32], and may treat psychiatric disorders that produce social pathologies [1,33]. ...
... These findings are complemented by studies that measure endogenous release of OT during a social task and then demonstrates that exogenous OT administration influences behavior in the same or similar task. This has been done for interpersonal trust [25,28,43] and charitable giving [30,44]. More generally, the prosocial effects of intranasal OT have been shown for a variety of situations, including punishment of free-riders [45] and the representation of social value [46] providing confidence that OT influences prosocial behaviors. ...
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.
... Oxytocin is a neuropeptide secreted by the posterior pituitary that has been suggested to enhance trustworthiness [1]. It reduces fear responses and enhances the ability to give trust to others, even in situations characterized by the risk of betrayal as measured with the Risk Game [2]. ...
... Risk-taking behavior is the extent to which someone makes choices that puts him/her in a vulnerable situation [10]. Oxytocin is often associated with trust and both perceived [11] and displayed [1] as trustworthiness, while it tends to reduce risk-taking behaviors under stressful circumstances, which can be seen as a more defensive reaction [12]. Testosterone decreases trust [13], while it enhances risk-taking behavior [67]. ...
Oxytocin has been proposed to enhance feelings of trust, however, these findings have been difficult to replicate. Environmental or hormonal factors might influence this association. We studied whether oxytocin moderates the association between the testosterone-cortisol ratio, which is associated with risk taking behavior and aggression, and trustworthiness, while controlling for the general level of trust. A randomized double-blind placebo-controlled study with 53 healthy males was performed in which 32IU oxytocin (n = 27) or placebo (n = 26) was administered intranasally. Participants subsequently played the Trust Game in which they were allocated to the role of trustee. In the third phase of the Trust Game, we found a positive association between the testosterone-cortisol-ratio and the proportion of the amount that is returned to the investor (P=<0.01). However, administration of oxytocin reduced reciprocity in those with a high testosterone-cortisol ratio after reciprocity restoration (a significant interaction effect between administration of oxytocin and the testosterone-cortisol ratio in the third phase of the Trust Game, P = 0.015). The third phase of the Trust Game represents the restoration of reciprocity and trustworthiness, after this is violated in the second phase. Therefore, our data suggest that oxytocin might hinder the restoration of trustworthiness and diminish risk-taking behavior when trust is violated, especially in those who are hormonally prone to risk-taking behavior by a high testosterone-cortisol ratio.
... In animal models, oxytocin has been demonstrated to increase social approach behavior, social recognition, social memory, and to reduce stress responses (Braida et al., 2012;Chang et al., 2014;Kubota et al., 1996;). In humans, oxytocin is known as a strong modulator of social behavior and increases gaze to eye regions, social cognition, social memory, empathy, perceptions of trustworthiness, and cooperation within one's own group (Bartz et al., 2010;Baumgartner et al., 2008;De Dreu et al., 2010;Domes et al., 2010;Di Simplicio et al., 2008;Ditzen et al., 2008;Dumais et al., 2016;Fischer-Shofty et al., 2018;Gabor et al., 2012;Guastella et al., 2008a;Guastella et al., 2008b;Keri et al., 2009;Kimura et al., 1992;Kosfeld et al., 2005;Mitre et al., 2016;Petrovic et al., 2008;Richard et al., 1991;Rimmele et al., 2009;Savaskan et al., 2008;Theodoridou et al., 2009;Zak et al., 2005;Unkelbach et al., 2008). ...
... Studies of intranasal oxytocin suggest equivocal effects on social behavior both generally and in ASD (Anagnostou et al., 2012;Andari 2010;De Dreu et al., 2010;Ditzen et al., 2008;Domes et al., 2010;Domes et al., 2013;Domes et al., 2014;Guastella et al., 2010;Guastella et al., 2015;Parker et al., 2017;Tachibana et al., 2013;Yatawara et al., 2015;Zak et al., 2005). The largest study in ASD to date did not demonstrate a signi cant improvement in social behavior with intranasal oxytocin (unpublished data). ...
Background
Phelan-McDermid syndrome (PMS) is a rare neurodevelopmental disorder caused by haploinsufficiency of the SHANK3 gene and characterized by global developmental delays, deficits in speech and motor function, and autism spectrum disorder (ASD). Monogenic causes of ASD such as PMS are well suited to investigations with novel therapeutics, as interventions can be targeted based on established genetic etiology. While preclinical studies have demonstrated that the neuropeptide oxytocin can reverse electrophysiological, attentional, and social recognition memory deficits in Shank3-deficient rats, there have been no trials in individuals with PMS. The purpose of this study is to assess the efficacy and safety of intranasal oxytocin as a treatment for the core symptoms of ASD in a cohort of children with PMS.Methods
Eighteen children aged 5-17 with PMS were enrolled. Participants were randomized to receive intranasal oxytocin or placebo (intranasal saline) and underwent treatment during a 12-week double-blind, parallel group phase followed by a 12-week open-label extension phase during which all participants received intranasal oxytocin. Safety was monitored throughout the study period and efficacy was assessed using the primary outcome of the Aberrant Behavior Checklist – Social Withdrawal (ABC-SW) subscale as well as a number of secondary outcome measures related to the core symptoms of ASD.ResultsThere was no statistically significant improvement with oxytocin as compared to placebo on the ABC-SW (Mann-Whitney U=50, p=0.055), or on any secondary outcome measures, during either the double-blind or open-label phases. Oxytocin was generally well tolerated and there were no serious adverse events.Limitations: The small sample size, potential challenges with drug administration, and expectancy bias due to relying on parent reported outcome measures may all contribute to limitations in interpreting results.Conclusion
Our results suggest that intranasal oxytocin is not efficacious in improving the core symptoms of ASD in children with PMS.Trial registration: NCT02710084
... Several reasons have been put forward to explain higher repayment rates among female borrowers. 4 Prior literature, for example, considers the trustworthiness of females as an important reason for higher repayment rates among female borrowers (Kosfeld et al., 2005;Zak et al., 2005;Carter, 2007). Based on data provided by Bangladeshi MFIs, Shahriar et al. (2020) show that better repayment performance by female borrowers can be largely explained by gender differences in innate trustworthiness, in which females dominate. ...
... Zak 2012), que intervendría en el aumento de la cooperación y con anza ya que, cuando ella está ausente, se observan altos niveles de desapego emocional en mamíferos, y otros desórdenes psicológicos, tales como la falta de empatía. Así, una de las hipótesis sobre la que trabajan algunos neurocientí cos a rma que la oxitocina es un factor causalmente relevante (o, en los términos P. Zak et al. 2005, 522 un factor modulador) para incrementar la tendencia hacia las conductas sociables. ...
En este trabajo sostenemos que debería existir un diálogo (que excluye la subordinación y la independencia) entre las neurociencias y las éticas normativas. Nuestro argumento toma como base que los conocimientos provenientes de la neurociencia (y, en particular, los estudios sobre el rol causal de la oxitocina en el comportamiento humano) pueden explicar y dar contenido a algunos límites motivacionales y psicológicos que modificarían las exigencias morales de los individuos. Mostramos que ante un caso hipotético que propone la mejora moral mediante la aplicación de oxitocina en aerosol, los argumentos neuroéticos, por sí solos, son insuficientes para determinar su permisibilidad o impermisibilidad moral. Además, defendemos que tampoco es posible establecer la superioridad de los argumentos de ética normativa, ya que los conocimientos de la neurociencia son más efectivos para modificar las conductas limitadas por nuestra propia constitución física y neurológica. Concluimos que tanto unos como otros sirven para tomar decisiones, tanto individuales, como colectivas, para tratar de acomodar mejor nuestras actitudes y comportamientos a lo que consideramos moralmente correcto hacer.
... An experimental study using the Trust Game by Kosfeld, Heinrichs, Zak, Fischbacher, and Fehr (2005) found evidence for a causal link between oxytocin and trust, which has later been disputed due to problems of replication (see a review by Alós-Ferrer and Farolfi (2019)). What remains relatively convincing is the evidence that being exposed to trustworthy behavior of others in the Trust game is indeed linked to higher levels of oxytocin (Zak, Kurzban, & Matzner, 2005) The reason why oxytocin matters is because evidence suggests it could be linked to our certainty of the future. Owen et al. (2013) find that oxytocin enhances cortical information transfer while simultaneously lowering background activity, thus improving the clarity of signal in the brain and reducing the background noise of neurons. ...
Large amounts of evidence suggest that trust levels in a country are an important determinant of its macroeconomic growth. In this paper, we investigate one channel through which trust might support economic performance: through the levels of patience, also known as time preference in the economics literature. Following Gabaix and Laibson (2017), we first argue that time preference can be modelled as optimal Bayesian inference based on noisy signals about the future, so that it is affected by the perceived certainty of future outcomes. Drawing on neuroscience literature, we argue that the mechanism linking trust and patience could be facilitated by the neurotransmitter oxytocin. On the one hand, it is a neural correlate of trusting behavior. On the other, it has an impact on the brain's encoding of prediction error, and could therefore increase the perceived certainty of a neural representation of a future event. The relationship between trust and time preference is tested experimentally using the Trust Game. While the paper does not find a significant effect of trust on time preference or the levels of certainty, it proposes an experimental design that can successfully manipulate people's short-term levels of trust for experimental purposes.
... Furthermore, there is scientific evidence that oxytocin is related to the motivation to avoid the suffering of others and the reinforcement of social behaviour [77,78,105]. By administering this substance to humans, they sacrifice more for others and become more trusting, reciprocal and generous [76,79,80,[106][107][108][109][110]. But oxytocin is not the only neurotransmitter that predisposes us to sociability and cooperation. ...
The new biotechnology raises expectations for modifying human behaviour through its use. This article focuses on the ethical analysis of the not so remote possibility of rehabilitating criminals by means of neurotechnological techniques. The analysis is carried out from a synthetic position of, on the one hand, the consequentialist conception of what is right and, on the other hand, the emphasis on individual liberties. As a result, firstly, the ethical appropriateness of adopting a general predisposition for allowing the neurorehabilitation of prisoners only if it is safe and if they give their consent will be defended. But, at the same time, reasons will be given for requiring, in certain circumstances, the exceptional use of neurotechnology to rehabilitate severely psychopathic prisoners, even against their will, from the same ethical perspective.
... system. A neurological reward may be derived from doing so (Zak et al. 2005(Zak et al. , 2009. Assume that the size of this sanction amounts to two points. ...
Modern democratic states are increasingly adopting new information and communication technologies to enhance the efficiency and quality of public administration, public policy and services. However, there is substantial variation in the extent to which countries are successful in pursuing such public digitalization. This paper zooms in on the role of social trust as a possible account for the observed empirical pattern in the range and scope of public digitalization across countries. Our argument is that high social trust makes it easier to digitalize the public sector to the benefit of overall society. We develop a simple game-theoretical model that specifies this positive externality from a high-trust culture and provide empirical evidence that a higher level of social trust is associated with a higher level of public digitalization. Of course, high-trust countries cannot do without the rule of law (formal rules of the game) and some institutionalized mechanisms of control and accountability. However, from our argument, it follows that one future challenge could be that control crowds out trust, so that the balance is no longer optimal. If such overcontrol occurs, public digitalization win–win situations between citizens and government can be undermined, even in high-trust countries.
... − Oxytocin soll zwischenmenschliches Vertrauen fördern (Kosfeld et al., 2005;Zak et al., 2005). In einer RCT war die Augmentation einer Expositionstherapie mit Oxytocin allerdings nicht erfolgreich (Guastella et al., 2009). ...
... Alternatives for future study include gaze [145], facial expressions, heart rate, and voice tracking [146], physiological measures such as EEG and GSR [141,142,143], which have been demonstrated to be useful for assessing trust within HRI or autonomous systems contexts. Other evaluations may also include hormone levels associated with trust such as elevated levels of oxytocin and lowered levels of testosterone [147,148,149], although these would be much more di cult to probe quickly. One may also evaluate trust in language grounding without special hardware but relying purely on observable behaviours, for example, how o en the human relies on the robot's u erances, what level of automation is taken, etc. e caveat to heed in the above is that these measures are not speci c to language grounding, so a careful coupling of scenarios relevant for language grounding must be presented. ...
The challenge of language grounding is to fully understand natural language by grounding language in real-world referents. While AI techniques are available, the widespread adoption and effectiveness of such technologies for human-robot teams relies critically on user trust. This survey provides three contributions relating to the newly emerging field of trust in language grounding, including a) an overview of language grounding research in terms of AI technologies, data sets, and user interfaces; b) six hypothesised trust factors relevant to language grounding, which are tested empirically on a human-robot cleaning team; and c) future research directions for trust in language grounding.
... Many claims have been made in the media and the scientific literature about oxytocin, from oxytocin being the trust hormone 7 (Honigsbaum 2011), to the "moral molecule" as "the new science of what makes us good or evil" or "the source of love and prosperity" (Zak 2001(Zak , 2012. Oxytocin has been also connected to human trustworthiness and increased generosity (Zak et al. 2005;Zak et al. 2007; Barraza and Zak 2009;. ...
In this chapter, psychopathy is used as an exemplar of a psychiatric condition with moral pathologies for which there is no truly efficacious treatment available but that could become a target for the implementation of brain intervention strategies. This chapter critically evaluates the feasibility, usefulness, and limitations of techniques or neurotechnologies in the diagnosis and treatment of individual with psychopathic traits. Neuroscientific developments have allowed, on the one hand, a better understanding of the structure and function of the nervous system, in particular the brain, giving the means to diminish the symptoms of some serious neuropsychiatric illnesses, but on the other hand, they have raised (unprecedented) ethical, legal, social, and clinical questions regarding possible risks of manipulation and abuse of neurotechnologies for brain interventions.KeywordsPsychiatryNeurotechnologiesPsychopathyDiagnosis and treatment of psychopathyMoral insanityNeurogenetics
... This is confirmed from several studies measuring endogenous levels of oxytocin and applying the intranasal inhalation of oxytocin. The first evidence of a relationship with social behaviors was that receiving a signal of trust was associated with higher levels of peripheral oxytocin, and that this endogenous level was also related to trustworthy behavior [22,23]. This was then further reinforced showing how during a classic trust game participants who received the exogenous oxytocin were more willing to trust an (until then unknown) investor and to take more financial risks, compared to the control group [24]. ...
Individual differences in temporal and probabilistic discounting are associated with a wide range of life outcomes in literature. Traditional approaches have focused on impulsiveness and cognitive control skills, on goal-oriented personality traits as well as on the psychological perception of time. More recently, literature started to consider the role of social and contextual factors in discounting behavior. Between others, higher generalized trust in human beings and specific trust in people who will deliver the future/probabilistic rewards have been related to a stronger willingness to wait and to assume risk. Moreover, the tendency to trust others has been associated with the oxytocin receptor gene regulation that can be modified by life experiences. In this perspective, we hypothesized that differences in the tendency to wait and to take risks for a more desirable reward according to the proposer’s trustworthiness could be related to a different level of DNA methylation at the oxytocin receptor gene. Findings confirmed that participants are less willing to wait and to risk when the proposer is considered highly untrustworthy and revealed how higher oxytocin receptor gene DNA methylation is associated with a stronger effect due to the presence of an untrustworthy proposer. Limits and future directions are outlined.
... Organizational justice has similar effects on measures of performance, though this concept is broader and generally encompasses organizational trust (Lewicki et al. 2005). We focus here on organizational trust because of recent research that has identified the neurochemical oxytocin as a key neurologic signal that motivates trustworthiness (Terris et al. 2018;Zak 2004Zak , 2005Zak , 2008. Laboratory experiments and field studies in organizations have demonstrated its powerful impact of human behavior and on multiple measures of organizational performance (Johannsen and Zak 2021;Zak 2017aZak , 2017bZak , 2018. ...
Trust in government institutions has been steadily declining, inhibiting the ability to serve the public effectively. We examined if organizational trust in five police departments (N = 531) affected job performance. The data show that trust improves on-the-job engagement (p = 0.0001) and enjoyment (p = 0.0000), reduces chronic stress (p = 0.0001), and is associated with a greater sense of purpose (p = 0.0000). We created a program to raise trust in one department and the data (N = 152) show that the intervention successfully increased organizational trust among program participants by 8.1% compared to nonparticipants. The program also had a positive effect on department performance, including a 6.1% increase in engagement, a 7.3% increase in job enjoyment, and a 10.5% increase in retention. Our analyses demonstrate that police leaders who create a culture of organizational trust achieve improved department performance.
... OT is also linked to social functioning. Enhanced social cognition (13)(14)(15)(16) and affiliative behaviors (17)(18)(19)(20)(21) were repeatedly reported to be associated with higher OT levels. People with a childhood maltreatment history often suffer from poor social functioning (22,23), such as disruptive behaviors and relational difficulties from early childhood to adulthood (24)(25)(26)(27), as well as impairment with social cognition (28)(29)(30). ...
Background: Child maltreatment is related to oxytocin (OT), which is related to social functioning. It may hamper the OT level to avoid a harmful situation and increase the OT level to adapt to the situation using a tend-and-befriend stress reaction.
Objective: This study aims to examine the association between the accumulation of moderate–severe childhood maltreatment and salivary OT levels in Japanese adolescents.
Participants: We used convenience samples of adolescents living in an institution ( n = 31) and those living with their parents ( n = 46).
Methods: Child maltreatment experiences were measured with the Childhood Trauma Questionnaire. The salivary OT levels were assessed by enzyme linked immunosorbent assay. A multivariate regression analysis was performed to see the association between the accumulation of child maltreatment types and the salivary OT levels adjusted for covariates (i.e., age, sex, and duration of institutionalization).
Results: Physical abuse was associated with higher OT, while emotional neglect showed an inverse association with OT. OT was the lowest with one maltreatment type group, which was significantly lower than the non-maltreatment group. As the number of maltreatment types increased from one maltreatment type to 2–3 types and to 4–5 types, OT also increased. This U-shaped association between the number of maltreatment types and OT was confirmed with the significant result of a square term of number of maltreatment type in the model ( p = 0.012).
Conclusion: We found herein a U -shaped association between the accumulation of child maltreatment and salivary OT levels. Also, different types of maltreatment had varied effects on the salivary OT. Further study is needed to elucidate the non-linear association between child maltreatment and OT levels.
... OT's effect on social bonding is evident in humans' primary parent-infant interaction during the postpartum period of parenthood (Gordon, 2010). Notably, previous studies focusing on plasma OT levels, showed that high levels of OT were associated with romantic attachment (Schneiderman, 2012) and human trustworthiness (Zak and Kurzban, 2005). However, in other studies high levels of OT were associated with stressful relationships in women (Taylor, 2010), greater attachment anxiety (Weisman et al., 2013), and more depressive symptoms (Parker et al., 2010). ...
Loneliness is prevalent in old age and is associated with reduced positive social interactions. Building on studies showing that oxytocin (OT) levels rise during social interactions, we hypothesized that following participation in positive social interaction involving synchronized movements, OT levels would increase, while state loneliness levels would diminish. A total of 63 older adults (aged M=78.93, SD= 9.99; range 65-101) participated in the study. Participants completed emotional and social loneliness scales and provided saliva samples pre- and post-participation in the “mirror game”, which requires movement synchronization and is known to promote connectedness and closeness. Results indicate a reduced state of loneliness following the mirror game. Importantly, the change in OT levels predicted the change in social loneliness, defined as the absence of social interactions with people in the social network. On the other hand, emotional loneliness, marked by deficient emotional contact, only decreased among participants who experienced high levels of closeness with their partner in the mirror game. Findings suggest that context-dependent change in endogenous OT may serve as biomarker for the social effects of oxytocin on loneliness in old age and can help in the development of targeted interventions for treating loneliness in old age.
... In one study, the fightor-flight response increased activation of the amygdala in participants with low oxytocin levels, which was associated with a lack of trust (15) in children who had experienced trauma. The association of oxytocin with trustworthiness was also demonstrated in an experimental adult's monetary payoffs study (16). Low plasma oxytocin levels have been observed in children who experienced trauma (17) and in adults who were exposed to childhood trauma (18). ...
Evidence has demonstrated the association between childhood trauma and criminality in adulthood, however, less is known about how best to explain the route from childhood trauma to adulthood aggression. Results from both human and animal studies have generated the hypothesis that dysfunction of the oxytocinergic system may correlate with pathological aggression. The current study represents a first exploratory examination to investigate the trajectory from childhood trauma to aggression, specifically, plasma oxytocin's role in this association. We assessed the childhood trauma experiences in a total of 108 participants, including 33 persons convicted for homicide and 75 non-offending healthy participants, using the Childhood Trauma Questionnaire, with in-depth clarification interviews for cross-validation. All participants were checked for aggression using the Modified Overt Aggression Scale and their plasma oxytocin levels were obtained. Results indicated that persons convicted for homicide had higher childhood trauma scores and lower plasma oxytocin levels than healthy controls. The plasma oxytocin levels were inversely correlated with childhood trauma in all participants. Further mediation models were constructed to explore these associations, in the best-fit model, the relationship between childhood trauma and aggression is mediated by plasma oxytocin levels in persons convicted for homicide. In conclusion, the association between childhood trauma and aggression of persons convicted for homicide is mediated by their plasma oxytocin levels. With leading to further theoretical consideration in the causality on how best to explain the interaction between childhood trauma and aggression, the current study may assist in developing further research and preventive strategies for aggression, particularly the importance of early identification of childhood trauma.
... Two 8-ml EDTA whole-blood tubes were drawn in a sterile field using Vacutainer 1 blood-collection kits. Tubes were stored on ice before being placed in a refrigerated centrifuge and spun at 1500 rpm at 4˚C for 12 min following previous protocols [67]. Plasma was aliquoted into 2-ml polypropylene Fisher brand microtubes that were immediately placed on dry ice and then transferred to an -80˚C freezer until analysis. ...
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.
... Conversely, being accused of cheating or lying was reported to be unpleasant (Petersen, Roepstorff, & Serritzlew, 2009). In addition, we also know that cooperating and mutually beneficial situations based on trust create a physiological benefit related to the release of oxytocin, the hormone often associated with in-group bonding, friendship, generosity, cooperation, and social bonding (Kosfeld, Heinrichs, Zak, Fischbacher, & Fehr, 2005;Zak, Kurzban, & Matzner, 2005). In other words, when voluntary cooperation has succeeded and a win-win situation achieved, then the neurological reward is a release of the "happiness" hormone oxytocin making continued cooperation between the involved parties even more likely (Petersen et al., 2009). ...
This chapter argues that trust nurtures face-to-face social interactions and can be strengthened through social and emotional competencies and the creation of policies that support the notions of community and belongingness in the corporate landscape.
... This might be of relevance as several functions have been identified for OXT in the last decade. Indeed, recent studies have suggested a role for this hormone in social behaviors such as trust [9][10][11][12][13] or couple formation [14,15] as well as in metabolism [16][17][18][19]. Another fact of particular importance is that OXT has been reported to play a role in sodium balance [20,21]. ...
Purpose The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a well-known complication of trans-sphenoidal pituitary surgery, related to inappropriate secretion of arginine vasopressin (AVP). Its diagnosis is based on hyponatremia, with a peak of occurrence around day 7 after surgery and, to date, no early marker has been reported. In particular, copeptin levels are not predictive of hyponatremia in this case. Oxytocin (OXT) is secreted into the peripheral blood by axon terminals adjacent to those of AVP neurons in the posterior pituitary. Besides its role in childbirth and lacta-tion, recent evidences suggested a role for OXT in sodium balance. The contribution of this hormone in the dysnatremias observed after pituitary surgery has however never been investigated. Methods We analyzed the urinary output of OXT in patients subjected to transsphenoidal pituitary surgery. Results While OXT excretion remained stable in patients who presented a normonatremic postoperative course, patients who were later diagnosed with SIADH-related hyponatremia presented with a significantly increased urinary secretion of OXT 4 days after surgery. Conclusion Taken together, these results show for the first time that urinary OXT output remains normally stable after trans-sphenoidal pituitary surgery. OXT excretion however becomes abnormally high on or around 4 days after surgery in patients later developing hyponatremia, suggesting that this abnormal dynamics of OXT secretion might serve as an early marker for transsphenoidal surgery-related hyponatremia attributed to SIADH.
This work investigates what motivates environmental action through developing a case study on how ecological conscience forms in the ritual practices of a new religious movement. I conducted a two-year ethnographic study with a community of contemporary Heathens in eastern and southwestern Ontario to investigate how ritual practices are related to the formation of conscience in the group. I used participant observation and interviews to investigate how ritual is related to conscience formation, and how it can generate a sense of obligation to others, including nonhuman others. I draw on social psychology (especially terror management theory), cognitive science, anthropology, ritual studies, and philosophy to describe and interpret three ritual practices, each of which involve some sort of gift giving. First I discuss high sumbel, a ritual of sharing drinks and giving gifts, then Dísablót, an example of ancestor veneration in which offerings (a type of gift) are given to the dead, and finally the procession of Nerthus, in which offerings are made to a figure participants understand as a power of nature associated with a particular bioregion. I find that giving gifts and expressing thanks in ritual inspires a sense of gratitude and a desire to give in turn in participants. Among these Heathens this gratitude and felt sense of obligation extends beyond human relations to include the more than human world. When one gives a gift one develops an appreciation for what one has already received, and when ritual activities include things that make participants aware of their mortality, the values that come to mind during the activity can be operationalized. In this case, values of inclusion, gratitude, sharing, and generosity are reinforced through ritual practice and influence participants’ dispositions, attitudes, and habitual behaviours.
This article reviews the neuroscientific understanding of the self and personal identity, focusing on various elements of inclusivity and exclusivity as well as engaging religious and spiritual perspectives. We will also consider how the identity is comprised of biological, social, and ideological or spiritual aspects, and how they are interconnected. We will consider how the brain helps us to construct and maintain our representation of the self and what happens when we have self‐transcendent experiences. Such an evaluation will have implications for understanding the intersection between consciousness and the self. This information will be helpful from both the psychological and spiritual perspective for understanding human identity.
I researched the effects of vulnerable leadership behaviors for my doctoral dissertation at William James College. I explored 3 different types of vulnerable leadership behaviors using psychophysiological measurements. My experimental research data showed that vulnerable leadership behavior was related to higher levels of psychological safety.
9.BASKI
Prof. Dr. Erdoğan KOÇ Prof. Dr. Erdoğan Koç 20 yılı aşkın bir süredir üniversitelerde lisans, yüksek lisans ve doktora seviyelerinde tüket c davranışı alanında dersler vermektedir. Yüksek cirolu markaların ürün yöneticiliği deney m de bulunan yazar 15 yılı aşkın bir süredir ulusal ve uluslararası şirketlere eğitimler vermekte ve danışmanlık yapmaktadır. Etki değeri yüksek ve saygın uluslararası dergilerde pek çok bilimsel çalışması bulunan yazar aynı zamanda pek çok saygın uluslararası bilimsel dergide editörler kurulu üyeliği ve hakemlik görevlerini de yürütmektedir. K tabın 9. baskısı bu deneyimlerin ışığında, Türkiye'de ve dünyada ortaya çıkan teorik ve pratik gelişmeler ve ihtiyaçlardaki değişimler göz önünde bulundurarak hazırlanmıştır. Kitapta Tüketici Davranışı ve Pazarlama Stratejileri 900'den fazla araştırma sonucu ve 1200' ün üzerinde ilginç örnekle desteklenerek, uygulama esaslı bir yaklaşımla anlatılmaktadır.
İşletmenin temel amacı müşteri yaratmak ve müşterileri tutmak olduğu için bir işletmenin iki (ve sadece iki) temel fonksiyonu vardır: pazarlama ve innovasyon (yenilikçilik). Pazarlama ve innovasyon (yenilikçilik) sonuç üretir. Diğer fonksiyonların hepsi maliyet üretir." (Peter Drucker) Tüketici sofistikasyonunun derinleştiği ve marka kalabalıklığının son derece arttığı günümüzde, tüketici davranışını anlamak ve uygun yenilikler pazarlama stratejileri ile hayata geçirmek işletmenin rekabet gücü geliştirmesini etkileyen en önemli unsurlardan biri haline gelmiştir. Araştırma sonuçları göstermektedir ki; i) müşteri memnuniyetindeki %1' lik bir artış yatırım üzerindeki getirinin yaklaşık olarak %12 artmasına ii) mevcut müşterilerin elde tutulma oranındaki %5'lik bir artış ise %25 la %125 arasında kâr artışına neden olmaktadır. iii) müşteri tatminindeki %1'lik bir artış müşteri sadakat oranının %10 artmasına neden olabilmektedir. Yen müşteri kazanmak eskiler muhafaza etmekten 5 kat daha maliyetlidir. Kitabı ders kitabı olarak kullanacak öğretim üyeleri yazar tarafından hazırlanmış sunumları yayin@seckin.com.tr adresinden isteyebilirler.
An anthology of works on the philosophy of economics, including classic texts and essays exploring specific branches and schools of economics. Completely revamped, this edition contains new selections, a revised introduction and a bibliography. The volume contains 26 chapters organized into five parts: (I) Classic Discussions, (II) Positivist and Popperian Views, (III) Ideology and Normative Economics, (IV) Branches and Schools of Economics and Their Methodological Problems and (V) New Directions in Economic Methodology. It includes crucial historical contributions by figures such as Mill, Marx, Weber, Robbins, Knight, and Veblen and works by most of the leading contemporary figures writing on economic methodology, including five Nobel Laureates in Economics.
Although many of us interact daily with animals, we have little understanding of how this affects our interactions with people. This study assessed the physiological effects of human-animal interactions and tested if this affected interpersonaltrust. Participants (N=141) were assigned to play with a friendly but unfamiliar cat or dog for 10 minutes or to rest quietly in a private room. Blood was obtained from human participants before and after animal interactions or rest, and videos of animal interactions were coded for encounter styles. Participants then made interpersonal monetary decisions to quantify trust and trustworthiness toward strangers. Although oxytocin (OT) fell on average after interactions with both dogs and cats, there was a positive and significant correlation between the change in OT after interacting with a dog and lifetime pet exposure. Participants who had lived with four or more dogs in their lifetimes had a positive increase in OT after interacting with an unknown dog. We found a negative correlation between the change in OT after interacting with a cat and cat ownership. Participants who had a reduction in stress hormones after a dog interaction showed increased trust in strangers. Specifically, a one-percentage-point decrease in the stress hormone adrenocorticotropin hormone increased trust in a stranger by 24 percent. Our findings show that the human OT response to animals depends on previous pet exposure.
In this chapter, we review studies comparing the social learning and cooperative abilities of wolves and dogs, both with conspecifics and humans. As regards social learning, their performance is similar in basic tasks involving local enhancement and observational memory. But when it comes to paying attention to the exact details of a demonstration and imitating a specific action, wolves clearly outperform dogs. Whether these differences stem from differences in cognitive abilities or rather from differences in general purpose mechanisms such as attention, working memory, inhibition or motivation still needs to be explored. As regards cooperation, the studies reviewed show that wolves and dogs share with us at least some of the abilities that seem to be important for cooperation: they show some prosocial tendencies, are inequity averse, can coordinate their actions with conspecific partners, and have a basic understanding of the role of their partner in cooperative interactions. However, the studies show that while wolves cooperate successfully with conspecifics as well as with human partners, dogs only succeeded with humans. This suggests that the dogs’ failure to cooperate with conspecifics is not due to cognitive limitations but rather due to limited tolerance towards each other in feeding contexts. While both species cooperate with humans, their behaviour revealed some remarkable differences suggesting that wolves rather lead (and perhaps just expect humans to follow), whereas dogs are more inclined to wait for the human partners to take the initiative and then follow their lead.
Increased interest in understanding how changes in the oxytocinergic system are associated with the etiology and progression of psychiatric disorders has currently boosted the publication of studies. We present a systematic literature review followed by meta-analyses assessing whether peripheral oxytocin (OXT) levels among psychiatric patients differ from healthy controls, considering the moderating role of methodological aspects and samples' characteristics. The following electronic databases were searched: PubMed, Web of Science, PsycINFO, SciELO, LILACS, and Scopus. Fifty-five papers were included in the analysis, and nine independent meta-analyses were performed according to the different diagnoses. Lower OXT concentrations were found in groups of specific disorders (i.e., schizophrenia, restricting and binge-eating/purging subtypes of anorexia nervosa, and borderline personality disorder) with medium to large effect sizes. Great heterogeneity was found among the studies, so that caution is needed to interpret the results. High OXT levels with an effect size of the same magnitude were found for bipolar disorder – type I and obsessive disorder. In contrast, no differences were found for bulimia, autism spectrum, depression, or social anxiety. No meta-analyses were performed for body dysmorphic disorder, post-traumatic stress disorder, or trichotillomania because only one study was identified for each of these disorders. Altered endogenous OXT concentrations are found in several disorders addressed and must be analyzed according to each disorder's specificities.
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.
More than 2000 years ago, the philosophers of ancient Greece suspected that personality was influenced by various fluids in the body. Today, researchers have made systematic efforts to understand the biological basis of personality, by studying substances such as neurotransmitters and hormones and also by studying the workings of the brain itself. In this chapter, we will take a quick look at the very early ideas about biological variables thought to underlie personality variation. We will then examine the recent theories that have been proposed to explain how personality variation might be influenced by various substances and brain structures, and we will discuss some of the research that has attempted to evaluate those theories.
This chapter outlines the current scientific realities associated with moral bioenhancement and presents a critical analysis of its feasibility from a neuroscientific and neurotechnological standpoint. Subsequently, a critique is offered of the conceptualization of human moral psychology by its proponents with a particular attention to the work of Julian Savulescu and Ingmar Persson. In a seminal article of 2008, they articulated the reasons why it is ethically desirable to enhance human moral capacities through technological means which culminated in their book Unfit for the Future: The Need for Moral Enhancement (2012). This chapter shows how proponents of moral bioenhancement fail to account for the complexity of morality and all that it means to be a moral agent.KeywordsJulian SavulescuIngmar PerssonMoral motivationScience and moral bioenhancementMoral agencyRevolution
Utilitarianism has been able to respond to many of the objections raised against it by undertaking a major revision of its theory. Basically, this consisted of recognising that its early normative propositions were only viable for agents very different from flesh-and-blood humans. They then deduced that, given human limitations, it was most useful for everyone if moral agents did not behave as utilitarians and habitually followed certain rules. Important recent advances in neurotechnology suggest that some of these human limitations can be overcome. In this article, after presenting some possible neuro-enhancements, we seek to answer the questions, first, of whether they should be accepted by a utilitarian ethic and, second, if accepted, to what extent they would invalidate the revision that allowed them to escape the objections.
Trust is essential for establishing and maintaining cooperative behaviors between individuals and institutions in a wide variety of social, economic, and political contexts. This book explores trust through the lens of neurobiology, focusing on empirical, methodological, and theoretical aspects. Written by a distinguished group of researchers from economics, psychology, human factors, neuroscience, and psychiatry, the chapters shed light on the neurobiological underpinnings of trust as applied in a variety of domains. Researchers and students will discover a refined understanding of trust by delving into the essential topics in this area of study outlined by leading experts.
The neuropeptide oxytocin (OXT) has been linked to interpersonal trust. While initial behavioral studies demonstrated a facilitating effect of OXT on trusting behavior, more recently these findings have been challenged. In this chapter we review the literature reporting two approaches that are used to evaluate OXT’s effects: exogenous OXT administration and the investigation of the endogenous OXT system. With respect to trust, we report results from studies investigating trusting behavior, mostly using economic games, and studies looking on the intention to trust other individuals. Overall, clear evidence for a direct trust-promoting effect of OXT as proposed by early studies cannot be found. Instead, there is evidence that the relationship between OXT and trust is modulated by manifold contextual factors that are closely interrelated, e.g., social affiliation, personality traits, gender, mental disorders, and genetic disposition. Furthermore, it could be argued that the effect of OXT on trust is not a specific one but only a subphenomenon of the more general prosocial effect of the neuropeptide.
Future research should aim to conceive models of the OXT–trust connection considering the interactions between genes, brain functioning, and the environment, advancing the knowledge of understanding interpersonal trust.
From a neurobiological point of view, in addition to pathological deviations in brain anatomy and physiology, alterations in brain chemistry are also relevant for violent behavior.
Background
Phelan-McDermid syndrome (PMS) is a rare neurodevelopmental disorder caused by haploinsufficiency of the SHANK3 gene and characterized by global developmental delays, deficits in speech and motor function, and autism spectrum disorder (ASD). Monogenic causes of ASD such as PMS are well suited to investigations with novel therapeutics, as interventions can be targeted based on established genetic etiology. While preclinical studies have demonstrated that the neuropeptide oxytocin can reverse electrophysiological, attentional, and social recognition memory deficits in Shank3 -deficient rats, there have been no trials in individuals with PMS. The purpose of this study is to assess the efficacy and safety of intranasal oxytocin as a treatment for the core symptoms of ASD in a cohort of children with PMS.
Methods
Eighteen children aged 5–17 with PMS were enrolled. Participants were randomized to receive intranasal oxytocin or placebo (intranasal saline) and underwent treatment during a 12-week double-blind, parallel group phase, followed by a 12-week open-label extension phase during which all participants received oxytocin. Efficacy was assessed using the primary outcome of the Aberrant Behavior Checklist-Social Withdrawal (ABC-SW) subscale as well as a number of secondary outcome measures related to the core symptoms of ASD. Safety was monitored throughout the study period.
Results
There was no statistically significant improvement with oxytocin as compared to placebo on the ABC-SW (Mann–Whitney U = 50, p = 0.055), or on any secondary outcome measures, during either the double-blind or open-label phases. Oxytocin was generally well tolerated, and there were no serious adverse events.
Limitations
The small sample size, potential challenges with drug administration, and expectancy bias due to relying on parent reported outcome measures may all contribute to limitations in interpreting results.
Conclusion
Our results suggest that intranasal oxytocin is not efficacious in improving the core symptoms of ASD in children with PMS.
Trial registration NCT02710084.
Für gewalttätiges Verhalten sind nicht nur pathologische Abweichungen der Hirnanatomie und -physiologie relevant, sondern auch der Hirnchemie. Diese wird von einer Vielzahl von Hormonen und neuronalen Überträgerstoffen beeinflusst. Die wichtigsten hiervon sind Testosteron, Ocytocin, Kortisol und Serotonin.
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.
Scientific progress leads to expect the possibility of enhancing moral abilities through neurological treatments. This article explores the extent to which such progress could be applied in the rehabilitation of psychopathic offenders. The goal is to answer the question of whether that biotechnological application is ethical.
Vasopressin and oxytocin are primarily synthesized in the magnocellular supraoptic and paraventricular nuclei of the hypothalamus and transported to the posterior pituitary. In the human, an extensive accessory magnocellular neuroendocrine system is present with contact to the posterior pituitary and blood vessels in the hypothalamus itself. Vasopressin and oxytocin are involved in social and behavioral functions. However, only few neocortical areas are targeted by vasopressinergic and oxytocinergic nerve fibers, which mostly project to limbic areas in the forebrain, where also their receptors are located. Vasopressinergic/oxytocinergic perikarya in the forebrain project to the brain stem and spinal cord targeting nuclei and areas involved in autonomic functions. Parvocellular neurons containing vasopressin are located in the suprachiasmatic nucleus and synchronize the activity of the pacemaker in this nucleus. From the suprachiasmatic nucleus fibers project to the parvocellular part of the paraventricular nucleus, where preautonomic neurons project to the intermediolateral nucleus in the thoracic spinal cord, from where the superior cervical ganglion is reached whose noradrenergic fibers terminate in the pineal gland to stimulate melatonin secretion at night. The pineal gland is also innervated by vasopressin- and oxytocin-containing fibers reaching the gland via the "central innervation" in the pineal stalk, which might be involve in an annual regulation of melatonin secretion.
Oxytocin (OT) promotes pro-sociality, bonding, and cooperation in a variety of species. Measuring oxytocin metabolite (OTM) concentrations in urine or saliva provides intriguing opportunities to study human and animal behaviour with minimal disturbance. However, a thorough validation of analytical methods and an assessment of the physiological significance of these measures are essential. We conducted an analytical validation of a commercial Enzyme Immunoassay (EIA; Arbor OT assay kit) to measure OTM concentrations in dog, wolf, and human urine samples. To test the assay’s ability to detect changes in OTM concentrations, we administered oxytocin intranasally to 14 dogs. Assay performance with regard to parallelism was acceptable. Assay accuracy and extraction efficiency for dog and wolf samples were comparable to a previously validated assay (Enzo OT assay kit) but variation was smaller for human samples. Binding sensitivity and antibody specificity were better in the Arbor assay. Average OTM concentrations were more than twice as high as in comparable samples measured with the Enzo assay, highlighting a lack of comparability of absolute values between different assays. Changes in OTM concentrations after intranasal treatment were detected reliably. The Arbor assay met requirements of a “fit-for-purpose” validation with improvement of several parameters compared to the Enzo assay.
This study introduces and provides evidence of an Evolutionarily Stable Signalling (ESS) System in the buyer-seller context through three experiments. An ESS system is one where a signaller (in this study, the seller) conveys positive intent to the receiver (customers) in a reliable manner that leads to the buyer’s benefits. This study uses the ‘felt’ or genuine smile of salespeople as a reliable signal. The non-consciously generated genuine smile of a salesperson leads to positive, trustworthy assessments by buyers. Buyers reach their conclusions about the trustworthiness of the salesperson rapidly and often without conscious evaluations. These studies simultaneously capture the response time and the cognitive assessments of the subjects. Their decision on the trustworthiness of the salesperson likely provides the foundation for subsequent cooperative exchanges. Using both response time and cognitive assessments allows these series of experiments to develop evidence of this ESS system in the present day.
This is a systematic review about the association between empathic behavior and oxytocin (OXT). Searches were conducted in the electronic databases PubMed, Web of Science, PsycINFO, SciELO, and LILACS using the search terms “oxytocin”, “empathy”, and “empathic”. Forty-four studies were reviewed. Scarce findings point to a lack of association between baseline endogenous OXT levels and empathy traits, and for a trend towards a direct relationship between oxytocinergic reactivity and empathic functioning. The results showed that variations in empathy were related to polymorphisms in the OXT receptor gene, especially in rs53576, and that this relationship seems to mediated by individual, ethnic, and cultural characteristics. Most studies on the exogenous administration of OXT tested a single dose (24 IU) with positive effects mainly on the affective domain of empathy. At the neural level, findings were inconsistent. Taken together, the results of the studies reviewed support the existence of a relationship between OXT and empathy that is complex and multifaceted. Robust evidence is still needed to elucidate existing links. Future investigations could benefit from methodological improvements aimed at increasing the reproducibility and applicability of findings, as well as the systematic assessment of the effects of exogenous OXT considering dose and frequency of administration, genotyping, and hormonal availability at the peripheral and central levels. This should lead to significant progress in the understanding of the therapeutic possibilities of OXT in the domain of empathic behavior.
Doktori értekezés.
(PhD dissertation in Hungarian.)
Short summary in English: https://www.researchgate.net/publication/350654228_The_Leap_of_Courage_Death_Anxiety_and_Social_Trust_Short_summary
Adam Smith’s two major works are based on apparently contradictory themes in human nature: noncooperative self-interest and other-regarding sympathy. These views are not contradictory if we distinguish impersonal market exchange and personal exchange. Noncooperative behavior in the former maximizes the gains from exchange, the basis of specialization and wealth creation. Cooperative behavior in personal exchange is based on reciprocity—trading gifts, favors, and assistance across time—which maximizes the gains from social exchange. That people can be both cooperative and noncooperative is corroborated in laboratory experiments and is postulated to stem from a self-interested propensity for exchange in markets and friendships.
Cooperation between individuals requires the ability to infer each other's mental states to form shared expectations over mutual gains and make cooperative choices that realize these gains. From evidence that the ability for mental state attribution involves the use of prefrontal cortex, we hypothesize that this area is involved in integrating theory-of-mind processing with cooperative actions. We report data from a functional MRI experiment designed to test this hypothesis. Subjects in a scanner played standard two-person "trust and reciprocity" games with both human and computer counterparts for cash rewards. Behavioral data shows that seven subjects consistently attempted cooperation with their human counterpart. Within this group prefrontal regions are more active when subjects are playing a human than when they are playing a computer following a fixed (and known) probabilistic strategy. Within the group of five noncooperators, there are no significant differences in prefrontal activation between computer and human conditions.
Oxytocin produces uterine contractions and milk ejection, functions related to parturition and nuturing. Studies were conducted to determine if this peptide, native to the brain and the posterior pituitary gland, plays a role in the induction of maternal behavior. Intact virgin female rats were given 0.4 mug of oxytocin, 0.4 mug of [Arg(8)]vasopressin, or saline through lateral ventricular cannulae. Forty-two percent of intact rats receiving oxytocin displayed full maternal behavior towards foster pups. None of the saline- or vasopressin-treated animals displayed full maternal behavior. Criteria in five behavioral categories had to be fulfilled by an animal within 2 hr of injection for its behavior to be considered fully maternal. When partial maternal responses were considered, oxytocin was significantly more effective than saline and marginally more effective than vasopressin. Five animals responding fully maternally after oxytocin injection were allowed to stay with pups for 10 days. All five continued to display full maternal behavior during this time. Nearly all animals that responded fully maternally to oxytocin injection were in the last day of diestrus or in proestrus or estrus. This suggested that elevated or recently elevated levels of estrogen may be necessary for the induction of full maternal behavior by oxytocin. Twenty-seven virgin female rats were ovariectomized and given either 100 mug of estradiol benzoate per kg in oil subcutaneously or oil alone immediately after operation. Forty-eight hours later, all animals received 0.4 mug of oxytocin intracerebroventricularly. Eleven of 13 estrogen-primed animals became fully maternal; none of 14 nonprimed animals became fully maternal.
Human cooperation is an evolutionary puzzle. Unlike other creatures, people frequently cooperate with genetically unrelated strangers, often in large groups, with people they will never meet again, and when reputation gains are small or absent. These patterns of cooperation cannot be explained by the nepotistic motives associated with the evolutionary theory of kin selection and the selfish motives associated with signalling theory or the theory of reciprocal altruism. Here we show experimentally that the altruistic punishment of defectors is a key motive for the explanation of cooperation. Altruistic punishment means that individuals punish, although the punishment is costly for them and yields no material gain. We show that cooperation flourishes if altruistic punishment is possible, and breaks down if it is ruled out. The evidence indicates that negative emotions towards defectors are the proximate mechanism behind altruistic punishment. These results suggest that future study of the evolution of human cooperation should include a strong focus on explaining altruistic punishment.
The existence of cooperation and social order among genetically unrelated individuals is a fundamental problem in the behavioural sciences. The prevailing approaches in biology and economics view cooperation exclusively as self-interested behaviour--unrelated individuals cooperate only if they face economic rewards or sanctions rendering cooperation a self-interested choice. Whether economic incentives are perceived as just or legitimate does not matter in these theories. Fairness-based altruism is, however, a powerful source of human cooperation. Here we show experimentally that the prevailing self-interest approach has serious shortcomings because it overlooks negative effects of sanctions on human altruism. Sanctions revealing selfish or greedy intentions destroy altruistic cooperation almost completely, whereas sanctions perceived as fair leave altruism intact. These findings challenge proximate and ultimate theories of human cooperation that neglect the distinction between fair and unfair sanctions, and they are probably relevant in all domains in which voluntary compliance matters--in relations between spouses, in the education of children, in business relations and organizations as well as in markets.
Estrogens control many physiological and behavioral processes, some of which are connected to reproduction. These include sexual and other social behaviors. Here we implicate four gene products in a micronet required for mammalian social recognition, through which an individual learns to recognize other individuals. Female mice whose genes for the neuropeptide oxytocin (OT) or the estrogen receptor (ER)-beta or ER-alpha had been selectively "knocked out" were deficient specifically in social recognition and social anxiety. There was a remarkable parallelism among results from three separate gene knockouts. The data strongly suggest the involvement in social recognition of the four genes coding for ER-alpha, ER-beta, OT, and the OT receptor. We thus propose here a four-gene micronet, which links hypothalamic and limbic forebrain neurons in the estrogen control over the OT regulation of social recognition. In our model, estrogens act on the OT system at two levels: through ER-beta, they regulate the production of OT in the hypothalamic paraventricular nucleus, and through ER-alpha, they drive the transcription of the OT receptor in the amygdala. The proper operation of a social recognition mechanism allows for the expression of appropriate social behaviors, aggressive or affiliative.
Trust is an essential component of transactions that occur over time. The amount of trust accorded to others is typically conditioned on multiple factors, including knowledge of the other party, the history of interactions, and the context of exchange. Determining who to trust and who to distrust is especially important in modern societies with largely impersonal exchange (Vernon L. Smith, 2003). In fact, trust is among the strongest predictors of whether a country will successfully develop: poor countries are by-and-large low-trust countries. This occurs because low trust inhibits investment and thereby the creation of wealth (Zak and Stephen Knack, 2001). Unfortunately, subjects in laboratory settings are unable to articulate clearly why they decide to trust or distrust a trading partner. In order to discover why human beings trust or distrust others, economists have begun obtaining physiologic measurements during trust experiments (Zak, 2005). This new transdisciplinary field is called neuroeconomics (Kevin McCabe et al.
Gender is rarely included as a factor in economics models. However, recent work in experimental economics, as well as in psychology and political science, suggests that gender is an important determinant of economic and strategic behavior. We examine gender differences in bargaining using the ‘‘trust game’ ’ introduced by Joyce Berg et al. (1995). 1 In this two-person game, the ‘‘proposer’ ’ is given a choice of sending some, all, or none of his or her $10 experimental payment to an anonymous partner, the ‘‘responder.’ ’ The experimenter triples any money sent. The responder then chooses how much of his or her total wealth (his or her $10 experimental payment plus the tripled money) to return to the proposer. Any money the responder does not return may be kept (thus the responder is playing a dictator game with his or her endowment plus three times the amount the proposer sent). The unique subgame-perfect Nash equilibrium is for the proposer to send no money and for the responder to return none. For U.S. subjects, Berg et al. found that 30 of 32 proposers deviated from this economic equilibrium and sent some money to their partners (the average amount sent was $5.16). In
Economic theories, particularly game theory, have been used widely to predict the behavior of markets and corporations. In a new twist, as Camerer explains in his Perspective, neuroscience is now informing game theory. Functional magnetic resonance imaging reveals the regions of the brain that "light up" during the cognitive and emotional events that accompany economic decision-making (Sanfey et al.).
Positive social interactions, including affiliations and social bonds, dominate the behavioral repertoire of humans and many higher vertebrates. Pair bonding is an evolved trait and may play a critical role in reproduction, as well as in individual and species survival. The neurobiology of pair bonding or other forms of social affiliation are most readily understood in this context. The purpose of this chapter is to examine mechanisms underlying social affiliation and social bonds, including research from rodents, sheep, and primates. We also discuss these findings in light of phylogeny, ontogeny, and the clinical implications of social bonding. Various forms of positive social behaviors, including pair bonding and maternal-infant behavior, rely on shared neural and endocrine systems. Steroid hormones, although integral to social and maternal bonding, do not exclusively code for these events; they also influence sexual behavior, feeding behavior, and exploratory behavior and thus have the recruiting capacity for a wide range of neural as well as somatic systems. Steroid hormones have their action in the brain by binding to DNA motifs at the promoter regions of certain genes, many of which code for neuropeptides and their receptors. Among the neuropeptides that support the formation and coordinate the autonomic and behavior states associated with bonding are oxytocin, endogenous opioids, vasopressin, and corticotropin-releasing hormone.
This paper introduces an emerging transdisciplinary field known as neuroeconomics. Neuroeconomics uses neuroscientific measuremen techniques to investigate how decisions are made. First, I present a basic overview of neuroanatomy and explain how brai 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 decision and social decisions. I conclude by identifying new directions that neuroeconomics is taking, including applications to publi policy and law.
Affect intensity is a stable individual difference characteristic defined in terms of the typical strength of an individual's responsiveness. Evidence is reviewed suggesting that the intensity of an individual's affective responsiveness generalizes across specific emotion categories, implying a general temperament dimension of emotional reactivity and variability. Two methods of assessing affect intensity are evaluated and found to exhibit desirable psychometric properties. Substantive research on the validity of the affect intensity construct is reviewed. Affect intensity is related to a variety of specific personality characteristics, has identifiable antecedents in childhood behavior, and relates to a broad range of cognitive, affective, and health-related consequences. An arousal regulation theory is proposed to account for individual differences in affective response intensity. Other plausible theories are mentioned, and directions for future research are discussed.
We reported previously a significant reduction of oxytocin (OT) receptor binding in the brain of 20-month old rats relative to 3-month old ones. The present study shows that testosterone treatment of aging rats restores normal adult levels of OT receptor binding in the olfactory tubercle and in the hypothalamic ventromedial nucleus, but not in the caudate–putamen. These data indicate that the reduced plasma testosterone found in 20-month old rats is responsible for the loss of OT receptors in the olfactory tubercle and hypothalamic ventromedial nucleus, whereas other aging-related mechanisms may account for the decrease of OT receptor binding in the caudate–putamen.
In the induced ovulator, Microtus ochrogaster (the prairie vole), daily injections of estradiol benzoate (EB 0.5 μg or 5.0 μg) facilitated high levels of sexual receptivity in ovariectomized females withing 48 hr of the onset of treatment. A lower level of EB (0.05 μg) with or without progesterone (0.5 mg) for five days did not induce lordosis. Four hr after sexually receptive EB-primed females received progesterone (0.5 mg) they either continued to show lordosis (EB 5.0 μg group) or showed an inhibition of lordosis (EB 0.5 μg group). Within 24 hr lordosis was markedly reduced in both groups. Progesterone-associated inhibitions were no longer apparent 48 hr after progesterone was discontinued. This general pattern of response to ovarian hormones is consistent with data described for other induced ovulators.
We designed an experiment to study trust and reciprocity in an investment setting. This design controls for alternative explanations of behavior including repeat game reputation effects, contractual precommitments, and punishment threats. Observed decisions suggest that reciprocity exists as a basic element of human behavior and that this is accounted for in the trust extended to an anonymous counterpart. A second treatment, social history, identifies conditions which strengthen the relationship between trust and reciprocity.
Video-based media spaces are designed to support casual interaction between intimate collaborators. Yet transmitting video is fraught with privacy concerns. Some researchers suggest that the video stream be filtered to mask out potentially sensitive ...
This paper presents a parameter covariance matrix estimator which is consistent even when the disturbances of a linear regression model are heteroskedastic. This estimator does not depend on a formal model of the structure of the heteroskedasticity. By comparing the elements of the new estimator to those of the usual covariance estimator, one obtains a direct test for heteroskedasticity, since in the absence of heteroskedasticity, the two estimators will be approximately equal, but will generally diverge otherwise. The test has an appealing least squares interpretation.
The steroid hormone progesterone (P4) is essential for establishing and maintaining pregnancy in mammals. One of its functions includes maintenance of uterine quiescence by decreasing uterine sensitivity to the uterotonic peptide hormone oxytocin. Although it is generally held that steroid hormones such as P4 act at a genomic level by binding to nuclear receptors and modulating the expression of specific target genes, we show here that the effect of P4 on uterine sensitivity to oxytocin involves direct, non-genomic action of P4 on the uterine oxytocin receptor (OTR), a member of the G-protein-coupled receptor family. P4 inhibits oxytocin binding to OTR-containing membranes in vitro, binds with high affinity to recombinant rat OTR expressed in CHO cells, and suppresses oxytocin-induced inositol phosphate production and calcium mobilization. These effects are highly steroid- and receptor-specific, because binding and signalling functions of the closely related human OTR are not affected by P4 itself but by the P4 metabolite 5beta-dihydroprogesterone. Our findings provide the first evidence for a direct interaction between a steroid hormone and a G-protein-coupled receptor and define a new level of crosstalk between the peptide- and steroid-hormone signalling pathways.
The neuropeptide oxytocin has been implicated in the mediation of several forms of affiliative behavior including parental care, grooming, and sex behavior. Here we demonstrate that species from the genus Microtus (voles) selected for differences in social affiliation show contrasting patterns of oxytocin receptor expression in brain. By in vitro receptor autoradiography with an iodinated oxytocin analogue, specific binding to brain oxytocin receptors was observed in both the monogamous prairie vole (Microtus ochrogaster) and the polygamous montane vole (Microtus montanus). In the prairie vole, oxytocin receptor density was highest in the prelimbic cortex, bed nucleus of the stria terminalis, nucleus accumbens, midline nuclei of the thalamus, and the lateral aspects of the amygdala. These brain areas showed little binding in the montane vole, in which oxytocin receptors were localized to the lateral septum, ventromedial nucleus of the hypothalamus, and cortical nucleus of the amygdala. Similar differences in brain oxytocin receptor distribution were observed in two additional species, the monogamous pine vole (Microtus pinetorum) and the polygamous meadow vole (Microtus pennsylvanicus). Receptor distributions for two other neurotransmitter systems implicated in the mediation of social behavior, benzodiazepines, and mu opioids did not show comparable species differences. Furthermore, in the montane vole, which shows little affiliative behavior except during the postpartum period, brain oxytocin receptor distribution changed within 24 hr of parturition, concurrent with the onset of maternal behavior. We suggest that variable expression of the oxytocin receptor in brain may be an important mechanism in evolution of species-typical differences in social bonding and affiliative behavior.
Sites which bind oxytocin and vasopressin with high affinity were detected in the brain and upper spinal cord of 12 human subjects, using in vitro light microscopic autoradiography. Tissue sections were incubated with tritiated vasopressin, tritiated oxytocin or an iodinated oxytocin antagonist. The ligand specificity of binding was assessed with unlabelled vasopressin or oxytocin in excess, as well as in competition experiments using synthetic structural analogues. The distribution of vasopressin binding sites differed markedly from that of oxytocin binding sites in the forebrain, while there was overlap in the brainstem. Vasopressin binding sites were detected in the dorsal part of the lateral septal nucleus, in midline nuclei and adjacent intralaminar nuclei of the thalamus, in the hilus of the dentate gyrus, the dorsolateral part of the basal amygdaloid nucleus and the brainstem. The distribution of oxytocin binding sites in the brainstem has been recently reported (Loup et al., 1989). Oxytocin binding sites were also observed in the basal nucleus of Meynert, the nucleus of the vertical limb of the diagonal band of Broca, the ventral part of the lateral septal nucleus, the preoptic/anterior hypothalamic area, the posterior hypothalamic area, and variably in the globus pallidus and ventral pallidum. The presence of oxytocin and vasopressin binding sites in limbic and autonomic areas suggests a neurotransmitter or neuromodulator role for these peptides in the human central nervous system. They may also affect cholinergic transmission in the basal forebrain and consequently play a role in Alzheimer's disease.
The effect of oxytocin on the ACTH, cortisol, GH and PRL response to physical exercise was investigated in 6 normal men. In addition, the possible involvement of endogenous opioids in the mediation of oxytocin action was evaluated. After fasting overnight, each subject was tested on four mornings at least 1 week apart. Exercise was performed on a bicycle ergometer. The workload was gradually increased at 3-min intervals until exhaustion and lasted about 20 min in all subjects. Tests were carried out under administration of oxytocin (2000 mIU as an iv bolus injection plus 32 mIU/min per 30 min) or naloxone (10 mg as an iv bolus injection) alone; furthermore, the effect of oxytocin together with naloxone (10 mg as an iv bolus injection) was evaluated. In the remaining test, normal saline was given instead of drugs. Plasma ACTH, cortisol, PRL and GH concentrations were significantly increased by physical exercise. Administration of oxytocin, naloxone or their combination was without effect on the PRL and GH rise elicited by exercise. In contrast, the exercise-induced ACTH and cortisol response was significantly raised by naloxone and reduced by oxytocin. When oxytocin was preceded by administration of naloxone, the ACTH and cortisol response to exercise was not reduced by oxytocin. These data show that oxytocin is capable of inhibiting the rise in ACTH and cortisol, but not in GH and PRL induced by physical exercise. Since naloxone abolished the inhibitory effect of oxytocin, oxytocin action on ACTH and cortisol secretion might be supposed to be mediated by an opioid pathway.(ABSTRACT TRUNCATED AT 250 WORDS)
Although an inability to form normal social attachments characterizes many forms of psychopathology, there has been little study of the neural basis of social bond formation. The primary purpose of this article is to describe a novel approach to the neurobiology of attachment.
The author reviews animal research on two closely related neuropeptides, oxytocin and vasopressin, implicated in the central mediation of attachment behaviors. These neuropeptides appear to be important for the initiation of pair bonds and parental behaviors as well as the infant's response to social separation.
Both cellular and molecular studies have begun to reveal the mechanisms by which oxytocin and vasopressin neural pathways are regulated, leading to a preliminary understanding of how these hormones act within the brain to influence complex social behaviors.
Although their function in the human brain has yet to be demonstrated, the available evidence suggests that oxytocin and vasopressin may prove to be important in the pathophysiology of clinical disorders, such as autism, characterized by an inability to form normal social attachments.
To investigate the effects of an ethologically-relevant stressor on central and peripheral release of arginine vasopressin and oxytocin, we forced adult male Wistar rats to swim for 10 min and simultaneously measured the release of the two peptides (i) within the hypothalamic supraoptic and paraventricular nuclei (by means of the microdialysis technique) and (ii) into the blood (by chronically-implanted jugular venous catheters). Forced swimming caused a significant rise in the release of arginine vasopressin and oxytocin within both the supraoptic nuclei (four-fold and three-fold, respectively) and the paraventricular nuclei (three-fold and four- to five-fold, respectively). Release patterns measured before, during and after repeated stress exposure on three consecutive days indicated that, at the level of the hypothalamus, the two neuropeptides are critically involved in the rats' stress response in a peptide-, locus- and stress-specific manner. Particularly, despite a general reduction of the recovery of the microdialysis probes over the time, the release of arginine vasopressin within the paraventricular nuclei and of oxytocin within the supraoptic nuclei tended to increase upon repeated stress exposure. Measurement of plasma peptide concentrations revealed that the central release of oxytocin was accompanied by a secretion of this peptide into the systemic circulation. In contrast, arginine vasopressin, assayed in the same plasma samples, failed to respond to the stressor. The latter finding is consistent with a dissociated release of the neuropeptide from different parts of a single neuron (soma/dendrites vs axon terminals). It provides evidence that under physiological conditions plasma hormone levels do not necessarily reflect the secretory activity of central components of the respective neuropeptidergic system.
Animal studies suggest that central vasopressin plays a facilitatory role in aggressive behavior. To examine this possibility in humans, the relationship between cerebrospinal fluid (CSF) arginine vasopressin (AVP) and indices of aggression and central serotonin system function was examined in personality-disordered subjects.
We used CSF (AVP), CSF 5-hydroxyindoleacetic acid, and the prolactin response to d-fenfluramine challenge (PRL[d-FEN]) as central indices of vasopressin and serotonergic system function, respectively, in 26 subjects who met the DSM-IV criteria for personality disorder. Measures of aggression and impulsivity included the Life History of Aggression assessment and the Barratt Impulsiveness Scales.
The CSF AVP level was correlated directly with life history of general aggression and aggression against persons and inversely with PRL[d-FEN] responses (but not with CSF 5-hydroxyindoleacetic acid), which in turn was correlated inversely with these 2 measures of life history of aggression. The positive relationship between CSF AVP and life history of aggression remained even when the variance associated with PRL[d-FEN] responses in these subjects was accounted for.
Central AVP may play a role in enhancing, while serotonin plays a role in inhibiting, aggressive behavior in personality-disordered individuals. In addition to the possibility of central AVP and serotonin interacting to influence human aggression, central AVP may also influence human aggressive behavior through a mechanism independent of central serotonin in personality-disordered subjects.
The purpose of this paper is to review existing behavioral and neuroendocrine perspectives on social attachment and love. Both love and social attachments function to facilitate reproduction, provide a sense of safety, and reduce anxiety or stress. Because social attachment is an essential component of love, understanding attachment formation is an important step toward identifying the neurobiological substrates of love. Studies of pair bonding in monogamous rodents, such as prairie voles, and maternal attachment in precocial ungulates offer the most accessible animal models for the study of mechanisms underlying selective social attachments and the propensity to develop social bonds. Parental behavior and sexual behavior, even in the absence of selective social behaviors, are associated with the concept of love; the analysis of reproductive behaviors, which is far more extensive than our understanding of social attachment, also suggests neuroendocrine substrates for love. A review of these literatures reveals a recurrent association between high levels of activity in the hypothalamic pituitary adrenal (HPA) axis and the subsequent expression of social behaviors and attachments. Positive social behaviors, including social bonds, may reduce HPA axis activity, while in some cases negative social interactions can have the opposite effect. Central neuropeptides, and especially oxytocin and vasopressin have been implicated both in social bonding and in the central control of the HPA axis. In prairie voles, which show clear evidence of pair bonds, oxytocin is capable of increasing positive social behaviors and both oxytocin and social interactions reduce activity in the HPA axis. Social interactions and attachment involve endocrine systems capable of decreasing HPA reactivity and modulating the autonomic nervous system, perhaps accounting for health benefits that are attributed to loving relationships.
Although the idea that aggression has biological components is not a new one, recent research in genetics, neuropsychopharmacology, and neuroimaging has helped clarify the biological contributions to aggression. Studies to date have focused on serotonergic function and impulsive aggression. Reduced levels of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) are associated with impulsive aggression. Pharmacochallenge studies have found decreased serotonergic responsiveness associated with impulsive aggression. Neuroimaging studies suggest a role for the prefrontal cortex, along with other regions of the brain, in the expression of aggression. Serotonin is not the only aspect of brain function implicated in impulsive aggression, and further work is being done on other neurotransmitters and neuropeptides.
It is difficult to think of any behavioural process that is more intrinsically
important to us than attachment. Feeding, sleeping and locomotion are all
necessary for survival, but humans are, as Baruch Spinoza famously noted,
"a social animal" and it is our social attachments that we live
for. Over the past decade, studies in a range of vertebrates, including humans,
have begun to address the neural basis of attachment at a molecular, cellular
and systems level. This review describes some of the important insights from
this work.
1. Violence and aggression are major public health problems. 2. The authors have used techniques of electrical brain stimulation, anatomical-immunohistochemical techniques, and behavioral pharmacology to investigate the neural systems and circuits underlying aggressive behavior in the cat. 3. The medial hypothalamus and midbrain periaqueductal gray are the most important structures mediating defensive rage behavior, and the perifornical lateral hypothalamus clearly mediates predatory attack behavior. The hippocampus, amygdala, bed nucleus of the stria terminalis, septal area, cingulate gyrus, and prefrontal cortex project to these structures directly or indirectly and thus can modulate the intensity of attack and rage. 4. Evidence suggests that several neurotransmitters facilitate defensive rage within the PAG and medial hypothalamus, including glutamate, Substance P, and cholecystokinin, and that opioid peptides suppress it; these effects usually depend on the subtype of receptor that is activated. 5. A key recent discovery was a GABAergic projection that may underlie the often-observed reciprocally inhibitory relationship between these two forms of aggression. 6. Recently, Substance P has come under scrutiny as a possible key neurotransmitter involved in defensive rage, and the mechanism by which it plays a role in aggression and rage is under investigation. 7. It is hoped that this line of research will provide a better understanding of the neural mechanisms and substrates regulating aggression and rage and thus establish a rational basis for treatment of disorders associated with these forms of aggression.
Naturally occurring variations in maternal licking/grooming influence neural development and are transmitted from mother to female offspring. We found that the induction of maternal behavior in virgin females through constant exposure to pups (pup sensitization) was significantly shorter in the offspring of High compared with Low licking/grooming mothers, suggesting differences in maternal responsivity. In randomly selected females screened for individual differences in maternal responsivity and subsequently mated, there was a significant and negative correlation (r = -0.73) between the latency to exhibit maternal behavior in the pup sensitization paradigm and the frequency of pup licking/grooming during lactation. Females that were more maternally responsive to pups and that showed increased levels of pup licking/grooming also showed significantly higher oxytocin receptor levels in the medial preoptic area, the lateral septum, the central nucleus (n.) of the amygdala, the paraventricular n. of the hypothalamus, and the bed n. of the stria terminalis. Intracerebroventricular administration of an oxytocin receptor antagonist to mothers on postpartum day 3 completely eliminated the differences in pup licking/grooming, suggesting that differences in oxytocin receptor levels are functionally related to maternal behavior. Finally, estrogen treatment of virgin females significantly increased oxytocin receptor binding in the medial preoptic area and lateral septum of female offspring of High, but not Low, licking/grooming mothers. These findings suggest that maternal licking/grooming influences the development of estrogen sensitivity in brain regions that regulate maternal behavior, providing a potential mechanism for the intergenerational transmission of individual differences in maternal behavior.
Cooperation based on reciprocal altruism has evolved in only a small number of species, yet it constitutes the core behavioral principle of human social life. The iterated Prisoner's Dilemma Game has been used to model this form of cooperation. We used fMRI to scan 36 women as they played an iterated Prisoner's Dilemma Game with another woman to investigate the neurobiological basis of cooperative social behavior. Mutual cooperation was associated with consistent activation in brain areas that have been linked with reward processing: nucleus accumbens, the caudate nucleus, ventromedial frontal/orbitofrontal cortex, and rostral anterior cingulate cortex. We propose that activation of this neural network positively reinforces reciprocal altruism, thereby motivating subjects to resist the temptation to selfishly accept but not reciprocate favors.
Numerous studies have implicated oxytocin (OT) and oxytocin receptors in the central mediation of social cognition and social behavior. Much of our understanding of OT's central effects depends on pharmacological studies with OT agonists and antagonists. Recently, our knowledge of OT's effects has been extended by the development of oxytocin knockout (OTKO) mice. Mice with a null mutation of the OT gene manifest several interesting cognitive and behavioral changes, only some of which were predicted by pharmacological studies. Contrary to studies in rats, mice do not appear to require OT for normal sexual or maternal behavior, though OT is necessary for the milk ejection reflex during lactation. OTKO pups thrive if raised by a lactating female, but OTKO pups emit fewer ultrasonic vocalizations with maternal separation and OTKO adults are more aggressive than WT mice. Remarkably, OTKO mice fail to recognize familiar conspecifics after repeated social encounters, though olfactory and non-social memory functions appear to be intact. Central OT administration into the amygdala restores social recognition. The development of transgenic mice with specific deficits in social memory represents a promising approach to examine the cellular and neural systems of social cognition. These studies may provide valuable new perspectives on diseases characterized by social deficits, such as autism or reactive attachment disorder.
Emotional stress activates oxytocin neurons in the hypothalamic supraoptic and paraventricular nuclei and stimulates oxytocin release from the posterior pituitary. Oxytocin neurons in the hypothalamus have synaptic contact with prolactin-releasing peptide (PrRP) neurons. Intracerebroventricular administration of PrRP stimulates oxytocin release from the pituitary. These observations raise the possibility that PrRP neurons play a role in oxytocin response to emotional stress. To test this hypothesis, we first examined expression of Fos protein, an immediate early gene product, in the PrRP neurons in the medulla oblongata after conditioned-fear stimuli. Conditioned-fear stimuli increased the number of PrRP cells expressing Fos protein especially in the dorsomedial medulla. In order to determine whether PrRP cells projecting to the supraoptic nucleus are activated after conditioned-fear stimuli, we injected retrograde tracers into the supraoptic nucleus. Conditioned-fear stimuli induced expression of Fos protein in retrogradely labeled PrRP cells in the dorsomedial medulla. Finally we investigated whether immunoneutralization of endogenous PrRP impairs oxytocin release after emotional stimuli. An i.c.v. injection of a mouse monoclonal anti-PrRP antibody impaired release of oxytocin but not of adrenocorticotrophic hormone or prolactin and did not significantly change freezing behavior in response to conditioned-fear stimuli. From these data, we conclude that PrRP neurons in the dorsomedial medulla that project to the hypothalamus play a facilitative role in oxytocin release after emotional stimuli in rats.
Economic theories, particularly game theory, have been used widely to predict the behavior of markets and corporations. In a new twist, as Camerer explains in his Perspective, neuroscience is now informing game theory. Functional magnetic resonance imaging reveals the regions of the brain that "light up" during the cognitive and emotional events that accompany economic decision-making (Sanfey et al.).
There is a considerable literature on the neurobiology of reward, based largely on studies of addiction or substance abuse. This review considers the possibility that the neural circuits that mediate reward evolved for ethologically relevant cues, such as social attachment. Specifically, mesocorticolimbic dopamine appears important for maternal behavior in rats and pair bonding in monogamous voles. It is not yet clear that dopamine in this pathway mediates the hedonic properties of social bond formation or whether dopamine's role is more relevant to developing associative networks or assigning salience to social stimuli. The neuropeptides oxytocin (OT) and vasopressin (AVP) appear to be critical for linking social signals to the mesocorticolimbic circuit.
Oxytocin receptors (OTR) and vasopressin V1a receptors (V1aR) in the ventral forebrain play critical roles in the formation of pair bonds in the monogamous prairie vole. Previous reports have been inconsistent in the identification of the specific brain regions in the ventral forebrain that express these receptors. To delineate more clearly the neuroanatomical boundaries of the OTR and V1aR fields in this species, we compared OTR and V1aR binding in adjacent brain sections and also with markers that delineate neuroanatomical boundaries in the ventral forebrain. OTR binding displayed an overlapping distribution with substance P mRNA and preproenkephalin mRNA, both markers for the shell and core of the nucleus accumbens. V1aR binding was nonoverlapping with each of these markers but colocalized with iron accumulation as shown by Perls' iron stain as well as leucine-enkephalin immunoreactivity, both markers for the ventral pallidum. OTR and V1aR mRNA were also restricted within the nucleus accumbens and ventral pallidum, respectively. Furthermore, destruction of ventral striatal dopaminergic terminals with 6-hydroxydopamine infusions into the nucleus accumbens did not alter OTR binding. Immunocytochemical analysis of oxytocin and vasopressin in the ventral forebrain demonstrated the presence of oxytocin-immunoreactive fibers in the nucleus accumbens and vasopressin-immunoreactive fibers in the ventral pallidum, with males showing a greater density of vasopressin fibers than females, but there was no such sex difference in the oxytocin system. Based on these results, we discuss potential neural mechanisms by which receptors in these brain regions mediate pair bond formation in this monogamous species. J. Comp. Neurol. 468:555-570, 2004.
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