Summary of:
Griskevicius, V., Tybur, J. M., Ackerman, J. M., Delton, A. W., Robertson, T. E., &
White, A. E. (2011, July 18). The Financial Consequences of Too Many Men: Sex Ratio
Effects on Saving, Borrowing, and Spending. Journal of Personality and Social
Psychology. Advance online publication. doi: 10.1037/a0024761
Summary by Domenico Decaro, Madeleine Higgins, Charlene Win, and Seneca Zamora.
For Dr. Mill’s Psych 310 class, Fall 2011
Introduction
The study “Financial Consequences of Too Many Men” by Vladas Griskevicius,
Joshua M. Tybur, Joshua M. Ackerman, Andrew W. Delton, Theresa E. Robertson and
Andrew E. White investigates the effect of sex ratio in human populations in financial
evidences such as spending, saving, and borrowing. It is examined in the cases of Macon,
Georgia and Columbus, Georgia as they are two cities exhibiting bipolar spending habits
with Columbus having intensely higher degrees of debt over Macon. This difference is
interpreted to be influenced by the gendered ratio bias in each city; Columbus having a
1.18 ratio of single men to women ratio and Macon having a .78 ratio of men to women.
Sex ratio is proposed to affect economic behavior as well as financial decision making
especially influencing same-sex competition for mates.
The researchers look to evolutionary biology in understanding how sex ratio
influences mating behavior. It is understood that in polygamous mating systems where
few males have all females(termed reproductive skew), sex ratio has little effect and
instead has great influence in monogamous mating systems. In mammals, male
reproductive success is more affected by the availability of mates in general and thus the
influence of imbalanced sex ratio will most likely be pronounced in males. Due to this,
male biased ratios will exhibit more intra-sexual competition for females and in female
biased ratios, males have less pressure to compete intra-sexually. These patterns are also
evidenced in humans in marriage systems such that in female biased ratios less parental
investment is exhibited and lower marriage rates occur while male biased ratios exhibit
opposite high parental investment and higher marriage rates; it is understood then that as
sex ratio changes behavior changes in the majority sex to compete for the minority
exhibiting traits that are desirable to the minority, and thus sex ratio naturally invites
intra-sexual competition in humans.
Evolutionary Biological findings in animal male biased populations are also
reflected in human populations suggesting a marked increase in violence and aggression
especially in intra-sexual competition; aggressive intra-sexual competition in humans can
be observed in men wanting to provide more resources when competing for mates. The
researchers assert that in human populations this competition is also observed in
economic behavior and expected spending when on romantic endeavors.
Study 4 examined how sex ratio affected the amount of expense men were
expected to deliver when on romantic endeavors in a male biased population. The
understanding is that in male-biased sex ratio men invest more in mating effort by
spending more for the prospective female. The researchers predicted that people in
general, both sexes, would expect men to spend more for a female when making romantic
endeavors in a male-biased sex ratio. The researchers examined the influence on
spending in the form of mating-related gifts providing the choice of a romantic
Valentine’s Day Gift, and entrée for a dinner date, and an engagement ring and surveyed
participants’ expectations.
Method
For the 4th study, the researchers used 147 university students and a 2 X 2
between subjects design, the factors being participant gender and the sex ratio exposed to
the participant (either male biased or female biased). Each participant was shown a
serious of faces. They were either shown more males than females, or more females than
males. Then, they were asked multiple questions concerning men’s spending behaviors
on Valentine’s Day, a dinner date, and an engagement ring. The participants rated how
much they thought a man should spend on each occasion on a 12 point scale of a range
amounts a man should spend; 1 being the least expensive and 12 being the most
expensive. The independent variable was sex ratio and the dependant variable was the
response on the financial questions.
Results
Both men and women expected men to pay more money on each occasion when
shown a male biased array of faces before answering the questions about spending. The
findings showed a main effect of gender, but not an effect of the interaction between
gender and sex ratio. When shown a male biased stimulus set before answering the
questions, participants on average thought men should $6.01 more on Valentine’s Day,
$1.51 more on a dinner date, and $368 more on an engagement ring than when they
viewed the female biased stimulus set. These results supported the hypothesis.
Figure 1
2600
50
2400
45
2200
2000
40
1800
35
Valentine's Day
Engagement
Ring
17
16.5
16
15.5
15
14.5
14
Dinner Date
Male Biased Sex Ratio
Male Biased Sex Ratio
Male Biased Sex Ratio
Female Biased Sex Ratio
Female Biased Sex Ratio
Female Biased Sex Ratio
Adapted from (Griskevicius et al., 2011, pp 8)
Conclusion
According the 4th study, which we focused primarily on, in a male biased sex ratio
society, people would expect men to spend more money. In addition, it did not appear
that at the completion of this study there was a correlation between Sex Ratio and the sex
of the participants in the study. In other words, both men and women seemed to think
that in a male biased sex ratio, men would tend to spend larger amounts of money. On
the other hand, though, the study found that men and women differed in their
expectations of how much money a man would actually spend in a male biased sex ratio
society. Both male and female participants could agree that the fewer women there
were in a given society, the more money a man would end up spending.
The sex ratio difference does not seem to have an affect or influence on a woman
wanting to acquire immediate financial gains, but it is clear that there is an effect on how
women expect men to spend the money that they make. As is what often happens from
an evolutionary standpoint, women are choosier about a male’s resources when there is a
male-biased sex ratio; that is, a woman can and does expect more when there are more
options that exist. While women carry this expectation, so too do the men have an
expectation of themselves in relation to the other males. The sense of competition and
exercising and demonstration of resources becomes far more prevalent when a society is
male-biased. While competition plays itself out for different species and throughout
different evolutionary spans of time, for men in American society, it appears that when
the feeling of being threatened, or the need of competition exists, men often resort to
using their money in order to demonstrate their reproductive value.
From the standpoint of the dichotomy of nature v.s. nurture, it appears through
this study that women in male -biased sex ratios select men who court them in the most
favorable way. Females choose a male with the intention of finding someone with the
best presentation of resources, so as to be able to nurture their future offspring in the most
successful way.
Outline
A. Introduction
1. Hypothesis – Men will spend more money for immediate gratification and
intrasexual competition due to a male biased sex ratio in the population
2. Applying animal behavior in regards to intrasexual competition
3. Male skewed sex ratio having the same effect on male human behavioral
patterns as male animal behavioral patterns
4. Intrasexual competitive behavior due to an evolutionary need to prove
adequate ability to provide for the female and their shared offspring
B. Methods – Study 4
1. 2 X 2 between subjects design
a. ID – Sex Ratio
b. DV – Response on Questionnaire to expected monetary investment
2. Participants viewed an array of faces either female biased or male biased
a. 147 participants (81 female, 66 male)
b. Answered questions based on a 12 point scale of how much money they
expected a man to spend on Valentine’s Day, an engagement ring, and a
dinner date
C. Results
1. Supported the hypothesis
a. Men were expected to spend more money on women when the population
had a male biased sex ratio
D. Conclusion/Discussion
1. These findings are different than what they found in China, so there are
discrepancies across culture
2. The authors fail to mention possible confounds
3. The research points to important evolutionary theory and paves the way for
future research
Test Questions
1. In the article written by Griskevicius et al., they found that a male biased sex
ratio…
a. Causes men to be more violent toward each other
b. Does not affect men
c. Causes men to spend more money on women
d. Causes women to be less choosy when picking a mate
2. The article The Financial Consequences of Too Many Men: Sex Ratio Effects on
Saving, Borrowing, and Spending, the IV was _________________ and the DV
was _________________ .
a. Sex ratio, Response to questions of spending
b. Response to questions of spending, Sex ratio
c. Gender, Response to questions of spending
d. Gender, Sex Ratio
3. Griskevicius et al. commented on the relationship between their findings and
findings from China. They found that when in a population with a male biased sex
ratio…
a. Chinese men behaved the same as American men
b. Chinese men behaved oppositely to American men
c. Chinese men were not affected by a male biased sex ratio
d. None of the above
4. Griskevicius et al., found that a female biased sex ratio causes men to spend more
money on women. (T/F)
5. Men have evolved to be more intrasexually competitive when they live in a
population with a male biased sex ratio. (T/F)
6. Because Chinese men save money to compete for women and American men
spend money to compete for women, there are cultural differences in the way
behaviors of men have evolved based on sex ratio (T/F)
Answer Key
1. C
2. A
3. B
4. F
5. T
6. T