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Study · Randomized controlled trial · 2020

2 results

Oxytocin and vasopressin modulation of prisoner's dilemma strategies.

Neto ML, Antunes M, Lopes M, Ferreira D, Rilling J, Prata D

Journal of psychopharmacology (Oxford, England)24 Mar 2020Cited by 15 (Europe PMC)

PMID32207359 (opens in a new tab)PMCIDPMC7583454 (opens in a new tab)DOI10.1177/0269881120913145 (opens in a new tab)PepBankPUB-32207359
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Summary

BackgroundThe neuropeptides oxytocin and vasopressin have been repeatedly implicated in social decision making by enhancing social salience and, generally, cooperation. The iterated and sequential version of the prisoner's dilemma (PD) game is a social dilemma paradigm eliciting strategies of cooperation versus competition.AimsWe aimed to characterise the role of PD players' sex, game partner type (computer vs. human) and oxytocin or vasopressin inhalation on the player's strategy preference.MethodsParticipants (153 men; 151 women) were randomised to intranasal 24 IU oxytocin, 20 IU vasopressin or placebo, double-blind, and played the PD. We examined main and interactive effects of sex, drug and partner type on strategy preference.ResultsWe found a pervasive preference for a tit-for-tat strategy (i.e. general sensitivity to the partner's choices) over unconditional cooperation, particularly when against a human rather than a computer partner. Oxytocin doubled this sensitivity in women (i.e. the preference for tit-for-tat over unconditional cooperation strategies) when playing against computers, which suggests a tendency to anthropomorphise them, and doubled women's unconditional cooperation preference when playing against humans. Vasopressin doubled sensitivity to the partner's previous choices (i.e. for tit-for-tat over unconditional cooperation) across sexes and partner types.ConclusionsThese findings suggest that women may be more sensitive to oxytocin's social effects of anthropomorphism of non-humans and of unconditional cooperation with humans, which may be consistent with evolutionary pressures for maternal care, and that vasopressin, irrespective of sex and partner type, may be generally sensitising humans to others' behaviour.
CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study2

2 results from studies that gave the peptide. 2 results from people.

  1. 01HumanRandomized controlled trialEfficacy outcome

    In women playing the prisoner's dilemma against computers, intranasal oxytocin doubled the preference for tit-for-tat over unconditional cooperation.

    In plain wordsIn women playing a cooperation game against computers, oxytocin doubled the preference for tit-for-tat play over unconditional cooperation.

    Peptide
    Oxytocin
    Outcome
    IncreaseTit-for-tat preference against computer partners in women
    Study

    n: not reported in source

    Comparator
    Placebo
    Outcome group
    Cognition and memory · Nervous system and cognition
    Studied dose
    24 IU · intranasalAs given in this study (human).

    Source sentences

    Summary
    Oxytocin doubled this sensitivity in women (i.e. the preference for tit-for-tat over unconditional cooperation strategies) when playing against computers
    1 context sentence
    Summary · context
    Participants (153 men; 151 women) were randomised to intranasal 24 IU oxytocin, 20 IU vasopressin or placebo, double-blind, and played the PD.
  2. 02HumanRandomized controlled trialEfficacy outcome

    In women playing the prisoner's dilemma against humans, intranasal oxytocin doubled the preference for unconditional cooperation.

    In plain wordsIn women playing a cooperation game against other people, oxytocin doubled the preference for unconditional cooperation.

    Peptide
    Oxytocin
    Outcome
    IncreaseUnconditional cooperation preference against human partners in women
    Study

    n: not reported in source

    Comparator
    Placebo
    Outcome group
    Cognition and memory · Nervous system and cognition
    Studied dose
    24 IU · intranasalAs given in this study (human).

    Source sentences

    Summary
    and doubled women's unconditional cooperation preference when playing against humans.
    1 context sentence
    Summary · context
    Participants (153 men; 151 women) were randomised to intranasal 24 IU oxytocin, 20 IU vasopressin or placebo, double-blind, and played the PD.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    11 Oct 2026, 00:50 UTC

    Study results updated

  2. Version 1

    9 Oct 2026, 02:48 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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