Social Influences on Health: The Role of Salivary
Progesterone (w/ Stephanie Brown)
The
neuroendocrine basis of social bonds is a growing area of
study that has important implications for our understanding
of relationship science, including links between social
contact, stress, and health (Brown and Brown, 2006). We
draw upon recent findings from neuroeconomics and
behavioral neuroendocrinology to predict that (a)
progesterone is part of the neuroendocrine basis of social
bonds in humans, and (b) reflects levels of
centrally-released oxytocin, which plays a role in reducing
stress and is restorative in terms of health. We have
preliminary evidence that social bonds account for patterns
of cooperative behavior similar to those shown in studies
from Behavioral Economics. We are seeking funding so that
we can analyze our salivary samples from our laboratory
experiment to test the hypothesized relationships between
social bonds and progesterone.
Status: internal grant request pending for analyzing
saliva samples collected during laboratory study
Stigmatized Targets, Investment Opportunities, and
Social Bonding (w/ Stephanie Brown)
We conducted an initial laboratory study to follow-up on
the work linking progesterone to social closeness in humans
using a behavioral economic paradigm that has been shown to
promote OT increase in blood samples (Zak et al., 2005).
Zak and his colleagues demonstrated that participants who
receive monetary transfers in a two-person investment game
had an increase in serum OT if they believed that a partner
sent the money of their own free will (as opposed to if the
money was sent because of a random draw). The OT increase,
in turn, was associated with higher monetary transfer sent
back. Researchers such as Zak and his colleagues have
interpreted these findings to indicate that OT increases
with perceptions of trustworthiness. While we do not
dispute this interpretation, we think that there is a
broader role for OT (and possibly progesterone) that is
being overlooked by neuroeconomics researchers. That is,
this finding can be interpreted as reflecting the fact that
OT is released by cues for interdependence that promote
social bonding and altruism, consistent with “Selective
Investment Theory,” advanced by the Co-PI (S. Brown &
R. Brown, 2006).
To examine this possibility and to test whether
progesterone would show a similar pattern to OT in a
neuroeconomics paradigm, we replicated the Zak et al. study
at the University of Michigan during the Winter term 2007.
We also collected saliva samples from participants to
examine whether financial interdependence is associated
with progesterone release in a similar fashion to OT
release. We have two main predictions: (1) Measures of
social bonds, as opposed to (or in addition to)
trustworthiness, will predict monetary transfers, but only
when cues for interdependence are strong (i.e., when the
partner has equal status to the participant but is not a
member of a stigmatized group—obese or extremely low
physical attractiveness, or does not exceed expectations
for physical attractiveness—extremely high physical
attractiveness); (2) Progesterone levels will rise in the
conditions representing strong cues for interdependence but
decline in conditions in which interdependence cues are
weak.
Status: data collected from 153 participants, draft
being written
