This study investigated the relationship between basal salivary progesterone levels and moral reasoning in 94 participants (24 males, 68 females). Participants provided saliva samples to measure progesterone and responded to a moral dilemma about a man considering stealing a drug to save his dying wife. Responses were coded for Kohlberg's stages of moral reasoning and for use of bond-centered justifications. Higher basal progesterone levels were associated with increased use of bond-centered moral reasoning, especially among females, even after controlling for word count. Progesterone level was unrelated to Kohlberg's stages of moral reasoning.

1. References
Contact Sara Konrath: skonrath@umich.edu
Sara Konrath gratefully acknowledges the Institute for Research on Women
& Gender at the University of Michigan for supporting this work.
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Summary
Progesterone plays a role in human bonding
behavior. We investigate how salivary PROG
is related to bond-centered moral reasoning.
We find that higher PROG is associated with
an increased use of bond-centered moral
justifications.
Background & Theory
Progesterone:
• A steroid hormone present in both males and
females
• PROG increases after randomly assigned
close social interactions (Brown et al., 2009)
• There is a positive correlation between PROG
and the need for affiliation (Schultheiss,
Dargel, & Rhode, 2003; Wirth & Schultheiss,
2006)
Moral reasoning
• Involves analyzing moral dilemmas with no
obvious right or wrong course of action
• Moral reasoning increases during childhood
but is stable in adulthood (Armon 1998)
• Moral reasoning scores linked with higher
prosocial behaviors and lower aggression and
delinquency (Arbuthnot et al, 1986;
Bredemeier, 1994 ; Eisenberg et al., 1989)
Research question
• Is there a possible relationship between bond-
centered moral reasoning and baseline
salivary PROG?
Methods
Progesterone
• Two salivary PROG levels were averaged
(α=0.88) to create a basal PROG score
• Saliva samples were analyzed via enzyme
immunoassay
Classic Moral Dilemma
Participants were asked whether a man
(Heinz) should steal a drug to save his wife or
abide by the law, accepting his unfortunate
circumstance (Colby & Kohlberg, 1987)
Participants were asked 5 questions about the dilemma, and the questions were coded by
research assistants blind to participants’ progesterone levels.
1) Should Heinz steal the drug? Why or why not?
2) Is it right or wrong for him to steal the drug? Why is it right or wrong?
3) Suppose the person dying is not his wife but a stranger. Should Heinz steal the drug for the
stranger? Why or why not?
4) It is against the law for Heinz to steal. Does that make it morally wrong? Why or why not?
5) In thinking back over the dilemma, what would you say is the most responsible thing for Heinz
to do? Why?
Results
Descriptive Statistics
Two Types of Coding:
1) Kohlberg’s stages of moral reasoning 2) Bond-centered moral reasoning
Discussion
Interpretations & Implications
• An increased use of bond-centered moral
justifications was associated with higher basal
PROG levels
• Kohlberg’s moral stages were unrelated to
PROG levels
• These effects especially apply to females, and
exist even when controlling for word count
• The results may imply that moral reasoning
may not be a stable trait, but may vary with
changes in hormone levels
Limitations & Future Directions
• Study is limited by relatively small and
homogenous sample
• In addition, we did not collect information on
hormonal birth control usage or timing of
menstrual cycle
• Finally, the correlational nature of the design
makes it impossible to determine the direction
of causality or the role of third variables
• Future studies should be conducted to
determine causal direction
• Other future studies could examine whether
moral reasoning changes with predictable
hormonal changes (e.g. menstrual cycle)
Males (N=24) Females (N=68) Overall (N=94)
Kohlberg stages (“traditional
coding”)
Level 1: 8.3%
Level 2: 50.0%
Level 3: 20.8%
Level 4: 20.8%
Level 1: 5.9%
Level 2: 29.4%
Level 3: 48.5%
Level 4: 16.2%
Level 1: 6.4%
Level 2: 34.0%
Level 3: 41.5%
Level 4: 18.1%
Bond-centered moral reasoning 1.50 (0.22) 2.03 (0.13) 1.76 (0.13)
Progesterone Time 1 84.84 (21.01) 147.91 (12.57) 116.38 (12.24)
Progesterone Time 2 73.88 (19.78) 129.47 (11.59) 101.68 (11.46)
Average PROG 77.93 (18.99) 136.71 (11.28) 107.32 (11.04)
0 50 100 150 200
Stage 4: Society at large
(N=17)
Stage 3: Community /
Interpersonal (N=39)
Stage 2: Individualism
(N=32)
Stage 1: Punishment /
obedience (N=6)
Male Female Bond-centered moral
reasoning (Scored as +1)
“Heinz is saving a loved one, his wife,
and people should help others in times
of need.”
Not bond-centered
(Scored as 0)
"Ultimately, when it comes down to
survival, the law becomes
secondary to life.”
Bond-centered responses summed à Scores could range from 0-5
progesterone (pg/ml)
progesterone(pg/ml)
0
50
100
150
200
250
300
Lowest (0 to 1) Middle (2 to 3) Highest (4 to 5)
Male Female
n/a
Gender: F(1,84)=7.59, p=.007
Kohlberg Stage: F(3,84)=0.39, p=.76
Interaction: F(3,84)=0.55, p=.65
Gender: F(1,87)=4.48, p=.037
Bond-centered reasoning: F(2,87)=3.25, p=.043
Interaction: F(1,84)=0.09, p=.77