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This study observes the effects of female cycle hormones on cooperation, competitiveness and risk preferences under experimental conditions. Especially, the causal effect of estradiol is isolated.
Behavioural theories assume that, as a result of natural selection, women undergo a brief, unconscious change in some psychological aspects during ovulation. This short-term change, "ovulatory shift", is assumed to aim to increase the probability of successful reproduction in the decisive days of the female cycle. Amongst others, it is assumed that women behave particularly uncooperatively and particularly competitively towards other women during the fertile days. Though, empirical evidence is ambiguous.
The effect on risk preferences is unclear. Theory generally assumes that female risk aversion increases in the fertile days. However, empirical studies find partly positive and partly negative correlations.
Within the scope of this study, estradiol levels which are collected in the clinical treatment of patients in the Clinic for Gynaecological Endocrinology and Reproductive Medicine are to be linked with the behavioural economic measures of cooperation, competitiveness, and risk preferences, which are collected using questionnaires or a computer-based decision task.
The aim of the research project is to quasi-experimentally isolate the effect of estradiol on competitiveness, cooperation and risk preferences of women.
No study known to us has ever been able to realize a comparable quasi-experimental design which is necessary to isolate the causal effect of estradiol on different behavioural measures.
In the experimental group, a sample of approx. 50 women in fertility treatment (In Vitro Fertilization/Intracytoplasmic Sperm Injection (IVF/ICSI), long Gonadotropin releasing Hormone (GnRH) agonist protocol) is surveyed. This allows us to create a quasi-experimental design in which the estradiol level is exogenously manipulated and regularly measured.
A random sample of 30 male students of Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University serves as a control group.
We realize a longitudinal section design with measurement repetitions, which allows inter- and intrapersonal comparisons. A three-stage procedure with two measuring points and a preliminary clarification meeting is planned.
The following measuring instruments are used to record competitiveness, cooperation and risk preference: SOEP Risk Attitude, Social Value Orientation German A, The cooperative and competitive Personality Scale German, Risk aversion, Willingness to compete.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| female patients | women in fertility treatment according to Long GnRH Agonist Protocol | ||
| control group | random sample of male students |
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| Measure | Description | Time Frame |
|---|---|---|
| Change of E2 [mg/l] | Change of blood concentration of estradiol (E2) in mg/l | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of LH [mg/l] | Change of blood concentration of the luteinizing hormone (LH) in mg/l | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Prog [mg/l] | Change of blood concentration of progesterone (Prog) in mg/l | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Cooperation 1 | Change of willingness to cooperate measured via the Social Value Orientation German A (Murphy et al. 2011) | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Competitiveness 1 | Change of willingness to compete measured via the cooperative and competitive Personality Scale German (Lu et al. 2006) | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Risk Preference 1 | Change of Risk preferences measured via the SOEP Risk Attitude (DIW Berlin) | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Cooperation 2 | Change of willingness to cooperate measured via the cooperative and competitive Personality Scale German (Lu et al. 2006) |
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Inclusion Criteria:
Patients
Control group
Exclusion Criteria:
Patients
Control group
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Women in fertility treatment
| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Jan Frederik Graff, Dr. | Contact | +49 241 8093341 | +492418027066 | Frederik.Graff@org.rwth-aachen.de |
| Benjamin Rösing, Dr. | Contact | +49 241 80 27066 | +492418027066 | broesing@ukaachen.de |
| Name | Affiliation | Role |
|---|---|---|
| Benjamin Rösing, Dr. | RWTH Aachen | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| RWTH Aachen University Hospital | Recruiting | Aachen | 52074 | Germany |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| Background | Ranehill, E., Zethraeus, N., Blomberg, L., von Schoultz, B., Hirschberg, A. L., Johannesson, M., & Dreber, A. (2017). Hormonal Contraceptives Do Not Impact Economic Preferences: Evidence from a Randomized Trial. Management Science. | ||
| Background | Durante, K. M., Griskevicius, V., Hill, S. E., Perilloux, C., & Li, N. P. (2010). Ovulation, female competition, and product choice: Hormonal influences on consumer behavior. Journal of Consumer Research, 37(6), 921-934. | ||
| 9633114 | Background | Gangestad SW, Thornhill R. Menstrual cycle variation in women's preferences for the scent of symmetrical men. Proc Biol Sci. 1998 May 22;265(1399):927-33. doi: 10.1098/rspb.1998.0380. | |
| Background | Buser, T. (2012a). Digit ratios, the menstrual cycle and social preferences. Games and Economic Behavior, 76(2), 457-470. |
| Label | URL |
|---|---|
| Website of the Deutsches Institut für Wirtschaftsforschung (DIW) Berlin with description and full questionnaires of the German Socio Economic Panel (SOEP) | View source |
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Estradiol via blood sample
| Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Competitiveness 2 | Change of willingness to compete measured via the Willingness to compete measure based on Niederle & Vesterlund (2007) | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Change of Risk Preference 2 | Change of Risk preferences measured via the Risk aversion measure by Holt & Laury (2002) | Approx. 10 days after application of GnRH agonist and again approx. 14 days later |
| Background | Buser, T. (2012b). The impact of the menstrual cycle and hormonal contraceptives on competitiveness. Journal of Economic Behavior & Organization, 83(1), 1-10. |
| Background | Wozniak, D., Harbaugh, W. T., & Mayr, U. (2014). The menstrual cycle and performance feedback alter gender differences in competitive choices. Journal of Labor Economics, 32(1), 161-198. |
| Background | Pearson, M., & Schipper, B. C. (2013). Menstrual cycle and competitive bidding. Games and Economic Behavior, 78, 1-20. |
| Background | Drichoutis, A. C., & Nayga, R. M. (2015). Do risk and time preferences have biological roots?. Southern Economic Journal, 82(1), 235-256. |
| 26824245 | Background | Lazzaro SC, Rutledge RB, Burghart DR, Glimcher PW. The Impact of Menstrual Cycle Phase on Economic Choice and Rationality. PLoS One. 2016 Jan 29;11(1):e0144080. doi: 10.1371/journal.pone.0144080. eCollection 2016. |
| 24065346 | Background | Murphy RO, Ackermann KA. Social value orientation: theoretical and measurement issues in the study of social preferences. Pers Soc Psychol Rev. 2014 Feb;18(1):13-41. doi: 10.1177/1088868313501745. Epub 2013 Sep 23. |
| 23145818 | Background | Lu S, Au WT, Jiang F, Xie X, Yam P. Cooperativeness and competitiveness as two distinct constructs: validating the Cooperative and Competitive Personality Scale in a social dilemma context. Int J Psychol. 2013;48(6):1135-47. doi: 10.1080/00207594.2012.743666. Epub 2012 Nov 12. |
| Background | Holt, C. A., & Laury, S. K. (2002). Risk aversion and incentive effects. American economic review, 92(5), 1644-1655. |
| Background | Niederle, M., & Vesterlund, L. (2007). Do women shy away from competition? Do men compete too much?. The Quarterly Journal of Economics, 1067-1101. |