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Monetary sacrifice among strangers is mediated by endogenous oxytocin release after physical contact By V. Morhenn, J. Park, E. Piper & P.J. Zak. Why Study Virtues? Virtuous behavior (by oneself and others) is associated with greater happiness (Haidt, 2006; Peterson & Seligman, 2004)
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Monetary sacrifice among strangers is mediated by endogenous oxytocin release after physical contact By V. Morhenn, J. Park, E. Piper & P.J. Zak
Why Study Virtues? • Virtuous behavior (by oneself and others) is associated with greater happiness (Haidt, 2006; Peterson & Seligman, 2004) • Robust evolutionary models for virtuous behavior do not exist (e.g. when an interaction is blinded) • Arguably, virtues are the social glue of relationships and societies • The neural substrates of virtues are not well understood
Questions • Why sacrifice to help a stranger when no one is looking? • Why sacrifice to a stranger when it is costly? • Why do we have the typical human ritual of pressing palms together (or sometimes bodies)? • Could these be related?
Sacrifice • From Middle English meaning "to make sacred” • Sometimes when you sacrifice something precious, you're not really losing it. You're just passing it on to someone else.
Rationale In rodents, and in some human studies, stroking releases OTQ: Is there any effect of endogenously released OT on social behaviors? HYPOTHESES: 1. Massage will increase OT 2. DOT will predict the degree of monetary sacrifice to a stranger
Oxytocin • Our lab has previously shown that • oxytocin is released by the brain when we are trusted by a stranger and is associated with trustworthiness • Oxytocin infusion can cause one to be more trusting toward a stranger • Oxytocin infusion can increase generosity towards a stranger substantially
Design Subjects randomized to receive eitherA) a 15min moderate pressure back massage by a licensed massage therapist, clothes on in a semi-private room, or B) rest quietly for 15mins in the same room.Subjects then play the trust game 1 time.Blood draw before massage and after decisions.A control group got a massage and blood draw but didn’t play the trust game.
The Trust Game Decision-maker 1 chooses some amount X of his/her $10 to send to decision-maker 2 Decision-maker 2 receives $3X, then can send all, some, or none back to decision-maker 1 Subjects receive $10 when they show up and are randomly and anonymously matched in pairs Trustworthiness Trust signal Blood draws
Definition • Sacrifice: A DM2 transfer in trust game that is greater than the average return – trustworthiness (or more strongly, unrelated to the amount received) • Nash Equil. predicts NO SACRIFICE
Findings • Groups • MT: massage+trust [MT], N=42; RT: rest+ trust N=30; M: Massage only N=24 • 53% female • OT change • M no change (basal OT=187.3 pg/ml, activated OT=189.5 picogram/mililiter, p=.62) • MT higher (basal OT=192.4 activated OT 221.5, p<.0001) • RT lower(basal OT= 256.9 activated OT 223.3, p=.006 ) In press
Findings $9.00 * $8.00 $7.00 $6.00 $5.00 Massage (MT) Rest (RT) $4.00 $3.00 $2.00 $1.00 $0.00 DM1 sent DM2 returned
Findings • OT & Behavior • DM1: DOTnot related to trust • DM2: DOT corr with signal of trust rec’d in MT (p=.03); weakly in RT (p=.10) • DOT predicts monetary sacrifice in MT and RT groups controlling for $ rec’d (p=.04) • OLS predicts that massage induces an extra $4.94 sacrifice (actual=$4.85) • RT: $ rec’d & DOT predict $ returned by DM2s; MT: only DOT matters (!)
Implications: Sacrifice • No gender diff in sacrifice (p=.32) • But…women were more susceptible to the massage prime (female basal OT 235.6 pg/ml, male basal OT =179.5 pg/ml, p=.05) • MT: higher basal OT => larger DOT (p=.05)…women drive our results! • Entire sample, Corr ( basal OT, DOT)= -.28, p=.007)
Implications • Female sacrifice to offspring is the hallmark of mammals, and OT appears to explain sacrifice to a stranger, esp. in women. • Touch appears to “prime” the release of OT • Why? OT causes ventromedial dopamine release. It may feel good to sacrifice (otherwise, why do it?)
Current Research Trust, Oxytocin and fMRI
Side Notes Trust and Oxytocin -Massaging Politicians could improve the country? -U turns signs -Dr. Muhammad Yunus and the Grameen Bank -Former English Subjects "No society can surely be flourishing and happy, of which by far the greater part of numbers are poor and miserable," Adam Smith (1776).