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.

•In rodents, and in some human studies, stroking releases OT

Q: Is there any effect of endogenously released OT on social behaviors?

Rationale

HYPOTHESES:

1. Massage will increase OT

2. OT will predict the degree of monetary sacrifice to a stranger

OxytocinOur 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

Subjects randomized to receive either

A) 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.

Design

Design

Subjects receive $10 when they show up and are randomly and anonymously matched in pairs

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

Trust signal

Trustworthiness

The Trust Game

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

Design

FindingsGroups

•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

$0.00

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

$7.00

$8.00

$9.00

DM1 sent DM2 returned

Massage (MT)

Rest (RT)

*

Findings

FindingsOT & Behavior

• DM1: OT not related to trust

• DM2: OT corr with signal of trust rec’d in MT (p=.03); weakly in RT (p=.10)

• OT 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 & OT predict $ returned by DM2s; MT: only OT 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 OT (p=.05)…

women drive our results!•Entire sample, Corr ( basal OT, OT)= -.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 ResearchTrust, Oxytocin and fMRI

Side NotesTrust 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).