The Neuropeptide Oxytocin Regulates Parochial Altruism in Intergroup Conflict Among Humans

De Dreu et al (2010)

By Alexander SanojaThe Neuropeptide Oxytocin RegulatesParochial Altruism in IntergroupConflict Among HumansGeneral StudyParochial altruism is a main factor of the studyaltruism that is directed in a preferential manner towards members of one's own social group

Effect of Oxytocin in a financial based experiments on in-group cooperation and defense against out-groupsImportant connectionsIn-group love is an indirect way of competing with an out-group

Out-group aggression is an indirect method of in-group cooperation

Darwin: groups with a greater number of courageous, sympathetic and faithful members, who were always ready to warn each other of danger, to aid and defend each otherwould spread and be victorious over other tribes.Oxytocin InfoOxytocin: neurotransmitter and a hormone and produced in the hypothalamus

Hits many parts of the brain: amygdala, hippocampus, brainstem, and parts of spinal cord that regulate ANS

Being close to kin raises oxytocin.High oxytocin receptor levels associated with empathy, generosity and the like.Oxytocin from a nasal spray promotes trust and cooperation and reduces taking advantage ofHypothesesWhen people organized in in-groups and competing out-groups increases in.1. in-group trust: the positive expectation that in-group members selfsacrifice to promote in-group welfare2. in-group love3. out-group hate: the inclination to aggress against the out-group to increase relative standing4. defensive out-group aggression: hostilityaimed at warding off out-group threat, such as premptive strikeAll experimentsComputer mediated, double-blind

Subjects given either oxytocin or a placebo intranasal.

30 minutes later: subjects assigned to 2 3-person groups on basis of trivial criterion. The groups were treated as the in-group with an associated out-group

Participated in confidential financial decision making game that had consequences on self and in/out groups.Experiment 1tested whether oxytocin stimulates in-group love and/or out-group hate49 participants playing prisoners dilemma game.Given 101 given to within-group pool meant +.50 to everyone in in-group including the contributor.1 given to between-group pool mean -.50 to everyone in out-group and +.50 to everyone in in-group including the contributor.

Experiment 1By results participants classified into 3 strategies: egoists, in-group lovers, out-group haters.

Participants afterwards asked to see how much group likely to put into in-group and out-group pools.

Oxytocin had an influence!

Researchers wonder if maybe cooperative individuals react more strongly to oxytocin.

Experiment 2tested whether oxytocin stimulates in-group love and/or out-group hate

Also if the effects of experiment 1 generalize across cooperative and non-cooperative individuals. 67 males took the social value orientations test (how a person would allocate resources on 9 occasions)Cooperator if 6/9 cooperative choices (25)Noncooperator if 6/9 noncooperative choices (42)

Experiment 2Oxytocin affected in-group love, but not out-group hate.

Disposition have independent but parallel effects on parochial altruism.

Affect on in-group trust, but not out-group distrust

Interesting to point out that out-group distrust higher on placebo regardless.Perhaps oxytocin modulates defensive aggression vs. an out-groupExperiment 375 males randomly assigned oxytocin/placebo nasal shot.Assigned to 1 of 4 between-group prison dilemmas

They make the decision to cooperate or not for their in-group. 3 confidential decisions.

T = Temptation, R = Reward, P = Punishment, S = SuckerT>R>P>S

The others just used numerical values.Experiment 3B: classified as high greed high fearC: high greed low fear D: low greed high fearE: low greed low fear

Higher non cooperation in B/C compared to D/E reflects greedy desire to exploit out-group

Higher non cooperation in B/D compared to C/E reflects anxious desire to protect in-group from possibly aggressive out-group

Experiment 3Participants at end took questionnaire. Whether they tried to defend their in-group against possible out-group noncooperation (protectionism), expected fellow in-group members to serve in-group interests by noncooperation toward the out-group (in-group trust), and expected out-group noncooperation

Experiment 3Hypothesis: oxytocin triggers noncooperation . Promotes noncooperation when out-group fear is high

Wanted to see if tendency of non cooperation stronger in high greed

Result: More noncooperation when out-group fear is high from oxytocin over placebo. No significance for greed. Treatment x fear interaction stronger with low greed

A: noncooperation in 3 triesB: Motivation to protect range 1-7C: in-group trust 1-7

Experiment 3Protectionism and in-group trust stronger among oxytocin and both correlated with participant noncooperation toward the out-group

out-group distrust showed no effects

Findings reflect a pattern in which oxytocin stimulates humans to aggress against an out-group to protect an in-groupConclusionWhen in-group vs out-group competition parochial altruism has strong survival function and is biologically linked to oxytocin.Oxytocin showed more in-group trust, not out-group distrust, defensive aggression vs. eminent out-group threat

Generalized across cooperators and noncooperators.

Concerns over studyOnly Males, but males are more impacted by between-group competition.

No answer to out-group hate, unless primarily grounded in perceived in-group love and protectionism in competing out-groups. Powerful out-groups could motivate protectionism and preemptive strike

Back To HaidtSupports the idea of oxytocin promoting groupish behavior

Since oxytocin and parochial altriusm shown to have a link it supports possible group selection within human beings in our history.

So does group selection exist in some form for humans?Would oxytocin spray have a similar impact on chimps?