Oxytocin promotes group-serving dishonesty

Shaul Shalvi 1, Carsten K W De Dreu

Abstract

To protect and promote the well-being of others, humans may bend the truth and behave unethically. Here we link such tendencies to oxytocin, a neuropeptide known to promote affiliation and cooperation with others. Using a simple coin-toss prediction task in which participants could dishonestly report their performance levels to benefit their group's outcome, we tested the prediction that oxytocin increases group-serving dishonesty. A double-blind, placebo-controlled experiment allowing individuals to lie privately and anonymously to benefit themselves and fellow group members showed that healthy males (n = 60) receiving intranasal oxytocin, rather than placebo, lied more to benefit their group, and did so faster, yet did not necessarily do so because they expected reciprocal dishonesty from fellow group members. Treatment effects emerged when lying had financial consequences and money could be gained; when losses were at stake, individuals in placebo and oxytocin conditions lied to similar degrees. In a control condition (n = 60) in which dishonesty only benefited participants themselves, but not fellow group members, oxytocin did not influence lying. Together, these findings fit a functional perspective on morality revealing dishonesty to be plastic and rooted in evolved neurobiological circuitries, and align with work showing that oxytocin shifts the decision-maker's focus from self to group interests. These findings highlight the role of bonding and cooperation in shaping dishonesty, providing insight into when and why collaboration turns into corruption.

Oxytocin modulates the racial bias in neural responses to others' suffering

Feng Sheng 1, Yi Liu, Bin Zhou, Wen Zhou, Shihui Han

Abstract

The intergroup relationship between a perceiver and a target person influences empathic neural responses to others' suffering, which are increased for racial in-group members compared to out-group members. The current study investigated whether oxytocin (OT), a neuropeptide that has been linked to empathic concern and in-group favoritism, contributes to the racial bias in empathic neural responses. Event-related brain potentials were recorded in Chinese male adults during race judgments on Asian and Caucasian faces expressing pain or showing a neutral expression after intranasal self-administration of OT or placebo. A fronto-central positive activity at 128-188 ms (P2) was of larger amplitude in response to the pain expressions compared with the neutral expressions of racial in-group members but not of racial out-group members. OT treatment increased this racial in-group bias in neural responses and resulted in its correlation with a positive implicit attitude toward racial in-group members. Our findings suggest that OT interacts with the intergroup relationship to modulate empathic neural responses to others' suffering.

Oxytocin increases anxiety to unpredictable threat

C Grillon,1 M Krimsky,1 DR Charney,1 K Vytal,1 M Ernst,2 and B Cornwell1

Abstract

The nonapeptide oxytocin (OT), dubbed by the media as the ‘moral’ or ‘love’ molecule, has a variety of pro-social effects across species. A relatively simple explanation for these complex effects is that OT alleviates anxiety,1 thereby indirectly promoting trust, cooperation and other affiliative behaviors.2,3 Indeed, OT can reduce anxiety-like behavior in animals, via its neuromodulatory influence on the amygdala, a core hub mediating fear and anxiety.4 Surprisingly, OT also promotes territoriality, aggression and other defensive behaviors toward out-group members,2 complicating any straightforward interpretation of OT’s socio-emotional effects. Here, we show that OT does not reduce but rather increases defensive responding to unpredictable threat in humans, suggesting that OT enhances anxiety.

A critical distinction has been recognized between two kinds of defensive states, sustained anxiety and phasic fear.5 Although the former is elicited by ambiguity and uncertainty (that is, unpredictable threat), the latter is evoked by explicit threat cues (that is, predictable threat).5 The hypothesis that OT differentially modulates defensive responses to unpredictable versus predictable threats directly follows evidence that OT released from the paraventricular nucleus of the hypothalamus facilitates excitatory signaling in the bed nucleus of the stria terminalis (BNST),7,8 a critical structure mediating defensive responses to unpredictable threats.5 In addition, OT receptor density varies by subdivision within the central nucleus of the rodent amygdala (CeA)4,6 and these subdivisions are differentially involved in defensive responses to predictable (fear) and unpredictable threats (anxiety). The medial CeA (mCeA) and lateral CeA (lCeA) are involved in fear and anxiety,5 respectively, but only the lCeA is rich in OT receptors.6 Finally, while in rodents endogenous OT reduces freezing to a fear conditioned cue,8 systemic OT administration does not affect fear-potentiated startle to a threat cue.9 Accordingly, we tested the possibility that OT may selectively increase defensive responding to unpredictable but not predictable threats using startle as a measure of fear and anxiety.5

Methods are fully described in Supplementary Information (see also Schmitz and Grillon10). We assayed startle reactivity, a well-established index of aversive state,5 in three conditions (see Figure 1) no shock (N), 2) predictable shocks (P) administered only during threat cues (red circles in the figure), and unpredictable shocks (U) administered randomly. Using a double-blind randomized within-subjects design, we administered placebo, OT, the structurally-related neuropeptide arginine vasopressin (AVP), and placebo (PLC) to 43 subjects in three sessions.

Oxytocin promotes human ethnocentrism

Abstract

Intergroup conflict is often driven by an individual's motivation to protect oneself and fellow group members against the threat of out-group aggression, including the tendency to pre-empt out-group threat through a competitive approach. Here we link such defense-motivated competition to oxytocin, a hypothalamic neuropeptide involved in reproduction and social bonding. An intergroup conflict game was developed to disentangle whether oxytocin motivates competitive approach to protect (i) immediate self-interest, (ii) vulnerable in-group members, or (iii) both. Males self-administered oxytocin or placebo (double-blind placebo-controlled) and made decisions with financial consequences to themselves, their fellow in-group members, and a competing out-group. Game payoffs were manipulated between-subjects so that non-cooperation by the out-group had high vs. low impact on personal payoff (personal vulnerability), and high vs. low impact on payoff to fellow in-group members (in-group vulnerability). When personal vulnerability was high, non-cooperation was unaffected by treatment and in-group vulnerability. When personal vulnerability was low, however, in-group vulnerability motivated non-cooperation but only when males received oxytocin. Oxytocin fuels a defense-motivated competitive approach to protect vulnerable group members, even when personal fate is not at stake.