A registered replication study on oxytocin and trust

In the paper

“A current leading theory to account for why OT can stimulate both prosocial and anti-social behaviors rests on neurological evidence that OT modulates mesolimbic dopaminergic neurons, thereby affecting both incentive motivation as well as attention re-orienting.”

What the sources say

• Not checked yetcites [7] Lambert, B., Declerck, C. H., Boone, C. & Parizel, P. M. A functional MRI study on how oxytocin affects decision making in social dilemmas: cooperate as long as it pays off, aggress only when you think you can win. Horm. Behav. 94, 145–152 (2017). source
• Partly supported

  The Final Comment (page not specified) proposes that oxytocin’s interaction with mesocorticolimbic dopamine circuits may alter motivational salience and value, potentially increasing attention to social stimuli and shifting behavior. The Introduction also links oxytocin to both positive and negative social behavior. But the paper calls this “another possibility,” not a leading theory, and presents the proposed mechanism more cautiously than the citing sentence does. (LLM, conf=0.84)

  cites [35] Love, T. M. Oxytocin, motivation and the role of dopamine. Pharmacol. Biochem. Behav. 119, 49–60 (2014). sourceExperimental — accuracy not yet measured
• Not checked yetcites [36] Shamay‐Tsoory, S. G. & Abu‐Akel, A. The social salience hypothesis of oxytocin. Biol. Psychiatry 79, 194–202 (2016). source

In the paper

“These studies were, however, not direct replications, i. e., they did not use the same methods and procedures as the original study.”

In the paper

“Money transfers in the trust game indicate that investors are willing to tolerate a certain level of uncertainty.”

In the paper

“The Kosfeld et al. study 8 already suggested this: OT increased trusting decisions in the trust game, but did not augment risk-taking in an identically framed risk game played against a computer.”

What the sources say

• Not checked yetcites [8] Kosfeld, M., Heinrichs, M., Zak, P. J., Fischbacher, U. & Fehr, E. Oxytocin increases trust in humans. Nature 435, 673–676 (2005). source

In the paper

“In humans, OT is mostly known for its functions in childbirth and breastfeeding, but it can also alleviate social stress, for example, by lowering salivary cortisol levels 4 , increasing parasympathetic control of the heart 5 , and attenuating amygdala activation in response to seeing faces 6,7 .”

What the sources say

• Not checked yetcites [4] Heinrichs, M., Baumgartner, T., Kirschbaum, C. & Ehlert, U. Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress. Biol. Psychiatry 54, 1389–1398 (2003). source
• Not checked yetcites [5] Norman, G. J. et al. Oxytocin increases autonomic cardiac control: moderation by loneliness. Biol. Psychol. 86, 174–180 (2011). source
• Not checked yetcites [6] Kirsch, P. Oxytocin modulates neural circuitry for social cognition and fear in humans. J. Neurosci. 25, 11489–11493 (2005). source
• Not checked yetcites [7] Lambert, B., Declerck, C. H., Boone, C. & Parizel, P. M. A functional MRI study on how oxytocin affects decision making in social dilemmas: cooperate as long as it pays off, aggress only when you think you can win. Horm. Behav. 94, 145–152 (2017). source

In the paper

“This question has sparked more than a decade of research ever since the first report that administering a single dose of intranasal OT (compared to placebo) increases the willingness to trust in a dyadic economic game with real monetary stakes 8 .”

What the sources say

• Not checked yetcites [8] Kosfeld, M., Heinrichs, M., Zak, P. J., Fischbacher, U. & Fehr, E. Oxytocin increases trust in humans. Nature 435, 673–676 (2005). source

In the paper

“Other critics have pointed out that there is no overarching theory to explain the diverse findings resulting from intranasal OT administration 20 .”

What the sources say

• Not checked yetcites [20] Churchland, P. S. & Winkielman, P. Modulating social behavior with oxytocin: how does it work? What does it mean? Horm. Behav. 61, 392–399 (2012). source

In the paper

“Because animal research has documented that OT is primarily a social bonding hormone that activates socio-emotional neural pathways in the brain 22,23 , we would also expect the effect of OT in humans to be limited to social situations where initiating or establishing partnership is important to realize synergy.”

In the paper

“Interestingly, the worry that another person may not reciprocate appears to influence transfers beyond the perceived riskiness of the game 9,10 , i.e., it is not just the risk of losing money but the fear of being cheated (i.e., betrayal aversion) that inhibits the investors' trust.”

What the sources say

• Not checked yetcites [9] Bohnet, I., Greig, F., Herrmann, B. & Zeckhauser, R. Betrayal aversion: evidence from Brazil, China, Oman, Switzerland, Turkey, and the United States. Am. Econ. Rev. 98, 294–310 (2008). source
• Not checked yetcites [10] Fehr, E. On the economics and biology of trust. J. Eur. Econ. Assoc. 7, 235–266 (2009). source

In the paper

“More specifically, Nave and colleagues 21 have raised doubt on the robustness of the oxytocin-trust association, pointing out that six studies failed to replicate the initial findings reported by Kosfeld et al. 8 .”

What the sources say

• Not checked yetcites [21] Nave, G., Camerer, C. & McCullough, M. Does oxytocin increase trust in humans? A critical review of research. Perspect. Psychol. Sci. 10, 772–789 (2015). source
• Not checked yetcites Kosfeld et al. 8

In the paper

“Because animal research has documented that OT is primarily a social bonding hormone that activates socio-emotional neural pathways in the brain 22,23 , we would also expect the effect of OT in humans to be limited to social situations where initiating or establishing partnership is important to realize synergy.”

What the sources say

• Not checked yetcites [22] Ross, H. E. & Young, L. J. Oxytocin and the neural mechanisms regulating social cognition and affiliative behavior. Front. Neuroendocrinol. 30, 534–547 (2009). source
• Not checked yetcites [23] Young, L. J. & Wang, Z. The neurobiology of pair bonding. Nat. Neurosci. 7, 1048–1054 (2004). source

In the paper

“To learn more about the biological basis of trust, researchers have investigated the potential causal link with the hormone oxytocin (OT), a neuropeptide with a central role in regulating social approach and attachment behaviors in many non-human mammals [1][2][3] .”

What the sources say

• Not checked yetcites [1][2][3]

In the paper

“In an influential paper, Kosfeld et al. (2005) showed that intranasal administration of Oxytocin (OT) increases the transfers made by investors in the trust game -suggesting that OT increases trust in strangers.”

What the sources say

• Not checked yetcites Kosfeld et al. (2005) source

In the paper

“We propose that minimal social contact is the cue that enhances the prosocial approach potential of OT and reduces social apprehension, thereby enhancing trust in an environment where approach behavior is a precondition for a mutually advantageous exchange.”

In the paper

“To bolster their results, Kosfeld et al. 8 assessed the global difference between all four experimental groups under consideration (trust/Placebo, trust/OT, risk/Placebo, and risk/OT) to ensure a family-wise error of α = 5%.The reported findings correspond to an η² = 0.071 (r = 0.267).”

What the sources say

• Not checked yetcites Kosfeld et al. 8

In the paper

“Despite the enormous resonance of the Kosfeld 8 et al. study, the minimal social contact feature of the study has often been overlooked or neglected.”

In the paper

“To enhance the saliency of the social context, participants in the trust game had some minimal social (faceto-face) contact with each other in groups prior to playing the game against someone whose exact identity would not be revealed.”

In the paper

“Our study will overcome these drawbacks because we will recruit a large sample that will enable us to use OLS regression techniques.”

In the paper

“By boosting the dopaminergic signal in the mesolimbic network, OT is thought to enhance the salience of social cues that emphasize the value of approach behavior 7,35,36 .”

What the sources say

• Not checked yetcites [7] Lambert, B., Declerck, C. H., Boone, C. & Parizel, P. M. A functional MRI study on how oxytocin affects decision making in social dilemmas: cooperate as long as it pays off, aggress only when you think you can win. Horm. Behav. 94, 145–152 (2017). source
• Not checked yetcites [35] Love, T. M. Oxytocin, motivation and the role of dopamine. Pharmacol. Biochem. Behav. 119, 49–60 (2014). source
• Not checked yetcites [36] Shamay‐Tsoory, S. G. & Abu‐Akel, A. The social salience hypothesis of oxytocin. Biol. Psychiatry 79, 194–202 (2016). source

In the paper

“Importantly, the social contact had to be minimal to avoid elevating trust to a level beyond which no further increase could reasonably be expected after OT administration.”

In the paper

“It turned out that intranasal OT significantly increased coordination on the mutually beneficial alternative strategy, but only if participants first had the opportunity to introduce themselves to the whole group of participants from which one was randomly drawn to become the partner.”

What the sources say

• Not checked yetcites [31] Declerck, C. H., Boone, C. & Kiyonari, T. Oxytocin and cooperation under conditions of uncertainty: the modulating role of incentives and social information. Horm. Behav. 57, 368–374 (2010). source

In the paper

“(ii) Social contact was not intense enough to cause strong feelings of social familiarity, as this might also generate a ceiling effect in trust.”

In the paper

“Since the publication of this study, increasing evidence suggests that OT's function is not always consistent with facilitating social approach, but that administering intranasal OT can also lead to parochial, competitive, and envious behaviors and behaviors that appear to be driven by schadenfreude 16,17,32 , which have an anti-social dimension.”

What the sources say

• Not checked yetcites [16] De Dreu, C. K. W. Oxytocin modulates cooperation within and competition between groups: an integrative review and research agenda. Horm. Behav. 61, 419–428 (2012). source
• Not checked yetcites [17] De Dreu, C. K. W. & Kret, M. E. Oxytocin conditions intergroup relations through upregulated in group empathy, cooperation, conformity, and defense. Biol. Psychiatry 79, 165–173 (2016). source
• Not checked yetcites [32] Shamay-Tsoory, S. G. et al. Intranasal administration of oxytocin increases envy and schadenfreude (gloating). Biol. Psychiatry 66, 864–870 (2009). source

In the paper

“Note, however, that the tests described in (ii) and (iii) in the Kosfeld study 8 are about comparisons between a trust and a risk game, which differ substantially from the current design which does not have a risk game (i.e., a game played against a computer).”

What the sources say

• Not checked yetcites Kosfeld study 8

In the paper

“We base our a priori power analysis on the effect size d = 0.514, reported in test (i) of Kosfeld et al. 8 and the requirement of a one-tailed test, which is justified when testing a directional 38 hypothesis.”

What the sources say

• Not checked yetcites Kosfeld et al. 8
• Not checked yetcites [38] Aron, A., Aron, E. N. & Smollan, D. Inclusion of other in the self scale and the structure of interpersonal closeness. J. Pers. Soc. Psychol. 63, 596–612 (1992). source

In the paper

“According to the a priori power analysis presented in detail below and the robustness check reported in Supplementary Information 1 and 2, a sample size of n = 704 will provide a statistical power of more than 95% for all main hypotheses and also exceeds the sample size recommendations of Nave et al.21 .”

What the sources say

• Not checked yetcites Nave et al.21 Nave, G., Camerer, C. & McCullough, M. Does oxytocin increase trust in humans? A critical review of research. Perspect. Psychol. Sci. 10, 772–789 (2015). source

In the paper

“Of the six studies that entered the meta-analysis in Nave et al.21 -in addition to the Kosfeld 8 et al. study -four studies had fictional partners [25][26][27][28] , one was completely devoid of human contact with other participants 29 , and participants' previous experience in a dictator game was likely to confound the decision to trust in the sixth study 30 .”

What the sources say

• Not checked yetcites [25][26][27][28]
• Not checked yetcites [29] Baumgartner, T., Heinrichs, M., Vonlanthen, A., Fischbacher, U. & Fehr, E. Oxytocin shapes the neural circuitry of trust and trust adaptation in humans. Neuron 58, 639–650 (2008). source
• Not checked yetcites [30] Barraza, J. A. The physiology of empathy: linking oxytocin to empathic responding. Diss. Abstr. Int. Sect. B Sci. Eng. 71, 4537 (2011).

In the paper

“Kosfeld et al. 8 were forced to use non-parametric tests in their study because their sample did not comply with assumptions made in parametric tests.Specifically, the smallest sample size in testing (i)-(iii) was n=29.”

What the sources say

• Not checked yetcites Kosfeld et al. 8

In the paper

“The proposed study will be carried out with the approval of the Medical Ethics Commissions of the Universities of Antwerp and Magdeburg.”

In the paper

“We deliberately collect information about these behaviors immediately after the experiment (i.e., after participants have been paid) so that they have no incentive to lie.”

In the paper

“Adding these two covariates will also reduce the standard errors in our treatment estimates -thus allowing sharper estimates -and correct for potential imbalances in the samples that occur through imperfect randomization.”

In the paper

“This stratification ensures that the distribution of individuals' SVOs will be the same in each treatment condition.”

In the paper

“A final criterion is participants' understanding of the trust game instructions.We will check this by letting them compute the monetary payoffs for both players in two hypothetical examples of the trust game.Both examples need to be solved correctly to be included in the data analyses.”

In the paper

“Measuring trust with a single decision (rather than averaging several consecutive decisions) has the advantage that it prevents hedge betting and may thus encourage intuitive thinking, which is the decision making type OT is most likely to influence, 7,47 rather than complicated deliberation.”

What the sources say

• Not checked yetcites [7] Lambert, B., Declerck, C. H., Boone, C. & Parizel, P. M. A functional MRI study on how oxytocin affects decision making in social dilemmas: cooperate as long as it pays off, aggress only when you think you can win. Horm. Behav. 94, 145–152 (2017). source
• Not checked yetcites [47] MacDonald, K. S. Sex, receptors, and attachment: a review of individual factors influencing response to oxytocin. Front. Neurosci. 6, 194 (2013). source

In the paper

“Total sample size 244 Actual Power 0.802”

In the paper

“SVO is a relatively stable personality feature describing a person's intrinsic willingness to behave prosocially 48 , that has been found to predict trusting decisions 49 and sensitivity to social cues 50 .”

What the sources say

• Not checked yetcites [48] Van Zijl., F. V. W., Timman, R. & Datema, F. R. Adaptation and validation of the Dutch version of the nasal obstruction symptom evaluation (NOSE) scale. Eur. Arch. Otorhinolary. 274, 2469–2476 (2017). source
• Not checked yetcites [49] Lipan, M. J. & Most, S. P. Development of a severity classification system for subjective nasal obstruction. JAMA Facial Plast. Surg. 15, 358–361 (2013). source
• Not checked yetcites [50] Teixeira, R. U. F., Zappelini, C. E. M., Oliveira, L. G., Basile, L. C. G. & Costa, E. A. Correlation between the peak nasal inspiratory flow and the visual analogue scale (VAS) before and after using a nasal decongestant. Int. Arch. Otorhinolary. 15, 156–162 (2011).

In the paper

“Such inter-individual differences might introduce excessive noise in the data which could obscure the results.”

In the paper

“Participants will be randomly assigned to one of the four treatment conditions (no contact/Placebo, no contact/OT, minimal social contact/Placebo, minimal social contact/OT) but randomization will be stratified based on participants' social value orientation (SVO) which will be measured during registration two weeks prior to the experiment with an online survey.”

In the paper

“Effect size d 0.320”

What the sources say

• Not checked yetcites Kosfeld et al. 3

In the paper

“To guarantee anonymity, their names will from then on be replaced by a self-made, retrievable code through which they can be identified during the remainder of the study.”

In the paper

“OT/placebo administration will be double blind following a randomized block design (with a block corresponding to a session).”

In the paper

“We do not plan to include social value orientation 48 as a covariate because we control for SVO via stratified randomization.”

In the paper

“First, the main motivation for the study is to replicate the Kosfeld et al. 8 study, which was conducted only with males.”

What the sources say

• Not checked yetcites Kosfeld et al. 8

In the paper

“A recent study investigating the dose dependency of oxytocin reports that a dose of 24 IU OT is more effective in triggering an amygdala response and eliciting fear reduction compared to either lower (12 IU) or higher (48 IU) doses 51 , although this contradicts an earlier study in which 8 IU was found to be the most effective 52 .”

What the sources say

• Not checked yetcites [51] Hsu, H. C. et al. Evaluation of nasal patency by visual analogue scale/nasal obstruction symptom evaluation questionnaires and anterior active rhinomanometry after septoplasty: a retrospective one-year follow-up cohort study. Clin. Otolaryngol. 42, 53–59 (2016). source

In the paper

“If participants are rated as non-compliant with the rules for self-administration (category 5) or the self-administration is judged as problematic by the supervisor (category 4) the participant is ruled out from data analysis.”

In the paper

“Second, we know from the previous literature that sex-specific gonadal steroids influence OT-receptor binding in the brain, and that intranasal oxytocin can affect the behavior of males and females differently, even in opposite directions 40 .”

What the sources say

• Not checked yetcites [40] Berg, J., Dickhaut, J. & McCabe, K. Trust, reciprocity and social history. Games Econ. Behav. 10, 122–142 (1995). source

In the paper

“The latter study, however, made use of a Breath Powered device for OT administration which is likely to have increased absorption significantly.”

What the sources say

• Not checked yetcites [52] Ten Velden, F. S., Daughters, K. & De Dreu, C. K. W. Oxytocin promotes intuitive rather than deliberated cooperation with the in‐group. Horm. Behav. 92, 164–171 (2017). source

In the paper

“The trust and risk measures will serve as control variables when testing the primary (a priori) hypotheses (described in the next section), while the other variables will serve as moderators in further exploratory analyses.”

In the paper

“Importantly, this questionnaire will query participants' beliefs regarding the treatment they received (OT versus placebo) which allows us to test the possibility of a placeboeffect.”

In the paper

“Actual power 0.951”

What the sources say

• Not checked yetcites G*Power 3.1.9.2 28

In the paper

“In sessions 6-11, participants were guided immediately to their cubicles upon arrival.This minimizes the contact with other participants before the experiment and increases our control over subjects social contacts.”

In the paper

“This complete lack of verbal interaction caused a strange and akward situation that was associated with reduced investments.”

In the paper

“Finally, a number of questions assess participants' feelings of connectedness with others, which can be used to test if the minimal social contact and no contact condition differed in this respect.”

In the paper

“They will also fill out the MDMS questionnaire for a second time.This will enable us to check for mood changes following nasal spray administration.”