Don't give an apology... It's just your biology?
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By Teleri Moore (z3377741), Zoe Harlen (z3374290), Thomas Barlow (z3377692), and Shani Lauf (z3287544)


Monogamy Versus Promiscuity


In today's society, even without the cultural expectation of monogamy, some humans still prefer to partake in monogamous relationships, and some to be promiscuous. It therefore makes sense to wonder whether it's not cultural expectations driving our preferred relationship interactions, but something more neurological.

The media item that our group has chosen to put under the neuroscience lens does just this. It is an online article from The Sydney Morning Herald (SMH) written by Mairi Macleod (a freelance science writer) describing some of the possible causes underlying human promiscuity and monogamy.

We aimed to discover not only whether the claims in the article were valid and based in a reputable neuroscientific context, but also what other factors could account for these behaviours.Due to the human cultural history of monogamy, and the recent upheaval into a sexually enlightened era, it is important to have a firm foundation of knowledge regarding the drive behind our behaviours, so we can gain a greater understanding and acceptance for them.


3.1. Definitions

The two main concepts our article deals with are monogamy and promiscuity. Monogamy has several meanings: it can refer to social monogamy- forming a pair for safety over reproductive reasons, sexual monogamy- having an exclusive sexual partner, and genetic monogamy- where DNA analyses confirm that a male-female partnership reproduce exclusively (Reichard, 2003). For the sake of this report and in regards to our chosen article, we have defined monogamy as a mix of social and sexual (or "sociosexual"), with an emphasis on the sexual side.

Promiscuity is a little more simplistic and therefore easier to define, and will be classified as a state which is "characterized by many transient sexual relationships" ("Promiscuity", 1989).

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Fig. 1: Hormonal control of the testes (Campbell, Reece, & Meyers, 2008)

3.2. Testosterone

3.2.1. The Biology of Testosterone:

Androgens are steroid hormones that support sperm production, and promote development and maintenance of male secondary sex characteristics. Testosterone is one of the main androgens. It is primarily produced in the testes, however small amounts are secreted by the adrenal gland. High levels of testosterone cause both physical and behavioural changes, such as facial hair, increased sex drive, and general aggressiveness(Campbell, Reece, & Meyers, 2008).

Androgens are controlled by the hypothalamic-pituitary-testicular axis. The hypothalamus secrets gonadotropin-releasing hormone (GnRH), which then stimulates the anterior pituitary to release the gonadotropins follicle stimulating hormone (FSH), and luteinizing hormone (LH). FSH and LH then target tissues in the gonads, stimulating the synthesis of testosterone. Increased testosterone inhibits the hypothalamic release of GnRH, and the pituitary release of FSH and LH. It does this through a negative feedback loop, which regulates androgen levels (Campbell et al., 2008).

3.2.2. Testosterone and Relationships:

A key conflict within male relationships is the trade off between putting effort into mating and competing with other males (or "male-male competition"), or putting time and energy into caring for partners and their children (Gray, Kahlenberg, Barrett, Lipson, & Ellison, 2002). Evidence suggests that testosterone promotes male-male competition and mate-seeking behaviours. However, in humans, drops in testosterone levels are correlated with the formation of the long-term relationships which precede parenthood. This suggests that testosterone levels may regulate mating and parenting behaviours (Gray, Chapman, Burnham, McIntyre, & Lipson, 2004).

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Fig. 2: Theoretical relationship of testosterone level (T) with the frequency and intensity of male-male aggression (upper) and the expression of parental behaviour (lower) (Wingfield, Hegner, Dufty, & Ball, 1990)

Wingfield’s and colleagues (1990) “challenge hypothesis” looks at the role of testosterone in mediating the above mentioned trade off between aggressive male-male competitions/mate-seeking behaviours, and parenting behaviours. The challenge hypothesis states that increases in testosterone are correlated with increases in aggression and mate-seeking behaviours, and are negatively correlated with paternal care.

Fig. 3: Salivary Testosterone Levels Across Conditions (Burnham et al., 2003)

Married men are proven to have lower testosterone levels in comparison to non married men... but only in the afternoon. Also, married fathers do not show significantly lower testosterone levels over married men who are without children (Gray et al., 2002). This is consistent with the challenge hypothesis. Furthermore, Burnham and colleagues (2003) found that the level of testosterone in males in long-term relationships was 21% lower than single men but there no significant difference between married men without children and men in relationships. This suggests that being in a relationship is the key predictor of testosterone, not marital status.

Van Anders and Watson (2006) found that testosterone levels are significantly less in partnered men in comparison to unpartnered men, and that being in a relationship (for those attracted to females) is connected to trait-specific, stable testosterone levels, as opposed to an individual's current levels.

Fig. 4: The 2D:4D ratio (Wikipedia, 2012)

Also, there is a direct correlation between right hand 2D:4D ratio and Sociosexual Orientation Inventory (Clark, 2004). The 2D:4D ratio describes the ratio of the index and ring finger on the right hand, where a smaller ratio is a predictor of higher pre-natal testosterone levels. The Sociosexual Orientation Inventory, or SOI, is used to ascertain how comfortable an individual is with engaging in causal sex. The article also went on to say that higher levels of testosterone (predicted using the 2D:4D ratio) correlated with higher occurrences of the participant partaking in uncommitted sex (Clark, 2004).

Further research shows that men in their first six months of a relationship have higher testosterone levels than men in long-term relationships and unpaired males. Furthermore, men in long-term relationships without prior relationship experience have lower testosterone levels than males with experience (Gray et al. 2004).

However, though the article mentions the promiscuity of women also possibly being so due to biological reasons, there is little evidence to support that the biological factors are similar to those which influence males. Testosterone is a hormone regulated in both males and females, however animal studies suggest that courtship behaviour in females is more dependent on increased steroid hormone sensitivity in certain brain areas, rather than elevated blood hormone levels for hormones such as testosterone (Voigt & Goymann, 2007). It would seem that elevated levels of testosterone in females is linked to increased territoriality and competition for mates, rather than promiscuity (Fivizzani & Oring, 1986).

3.2.3. Summary:

There is clear evidence in the neurological context that testosterone levels are correlated with things such as relationship status, parenting, physical features, sociosexuality, etc. These may be seen as indicators of monogamy or promiscuity, therefore testosterone levels may play a facilitating role in the representation of these behaviours (Gray et al., 2002; Gray et al., 2004).

However, it is important to note that these correlations in testosterone levels and relationship/parental status do not mean causation (Gray et al., 2002; Gray et al., 2004). This suggests the need for more longitudinal data on testosterone levels, so it can be understood whether being in a relationship drops testosterone levels, or whether testosterone levels determine the likelihood of entering a long-term relationship. (Burnham et al., 2003)

3.3. Oxytocin and Vasopressin (ADH)

Oxytocin vasopresion production .png
Fig. 5: Production and release of posterior pituitary hormones (Campbell, Reece, & Meyers, 2008)

When discussing the neurological functions underpinning mating and sociosexual orientation, literature on the effects of vasopressin (ADH) and oxytocin should be included. Macleod fails to do so in the article, however we have incorporated information on both hormones as they are critical in driving mating habits.

3.3.1. Oxytocin:

Oxytocin is a nonapeptide hormone, expelled from the posterior pituitary and generated by the hypothalamus (Wathes & Swann, 1982). Previous animal studies have shown it to be an important factor in reproduction, the regularity of sexual emotions and receptivity for females, and is released during mating in males (Waldherr & Neumann, 2007). Insel et al. (1995) also found that this effect extended into mammals.

3.3.2. Vasopressin:

Animal studies into vasopressin (a neurohypophysical hormone found in most mammals) have found that it facilitates monogamous pair-bonding, partner preference, and paternal behaviour in males (Insel & Hulihan, 1995; Young, Winslow, Nilsen, & Insel, 1997). Therefore testosterone is not the only important hormone in play when determining levels of promiscuity and monogamy exhibited vasopressin neurotransmission occuring in the ventral pallidum during mating is necessary for pair-pond formation and social attachment (Lim & Young, 2004).

3.3.3. Summary:

While Macleod fails to make mention of the significant effects of oxytocin and vasopressin on female and male attachment respectively, it is clear that evidence exists showing that there are strong links between levels of these hormones and reproductive behaviour. Thus, a person's monogamous or polygamous tendencies may be heavily influenced by levels and expression of these hormones at various times during their life. This more supports the hypothesis that Macleod is underlining throughout the article, that monogamy and promiscuity are merely products of our biological make-up.

3.4. Ovulation

3.4.1. The Biology of Ovulation:

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Macleod (2008) mentions in the article that “women are more likely to fancy a fling around the time they are ovulating- although there is no suggestion that this is a conscious decision”. The non-conscious decision that Macleod is referring to is the influence of various phases of the menstrual cycle on fertile women, driving them to have more polygamo
Fig. 6: The reproductive cycle of the human female (Campbell, Reece, & Meyers, 2008)
us tendencies during the ovulatory phase.

The menstrual cycle is a system of physiological changes in females that allow reproductive processes to occur. On average it is a 28-day cycle, and consists of three main phases: the follicular phase, ovulation and the luteal phase (Greenberg, Bruess & Conklin, 2007).

The follicular phase initiates the menstrual cycle, lasting from day 1 to 13, and contains the menstruation phase. Increases in levels of the follicle stimulating hormone (FSH) cause the development of ovarian follicles, which secrete increasing amounts of estrogens (Losos, Raven, Johnson & Singer, 2002, Campbell, 2010). This estrogen initiates the formation of a layer of endometrium in the uterus (Weschler, 2002). The menstruation phase usually lasts from day 1 to 4. See Figure 3 opposite, showing the production of estradiol (a type of estrogen).

Ovulation lasts from day 13 to 16 of the menstrual cycle. It begins with estrogen stimulating the hypothalamus, initiating production of Gonadotropin-releasing hormone (GnRH), which in turn produces a large amount of luteinizing hormone (LH) from the anterior pituitary gland (Lentz, Lobo, Gershenson & Katz, 2012). LH finalises the growth of an ovum (Gray, 2000).

The luteal phase makes up the remaining 12 days of the cycle. The corpus luteum (within the ovary) continues growing after ovulation, and produces the hormone progesterone. Increased levels of progesterone in the adrenals cause production of estrogen once again, and then reducing levels of progesterone initiate menstruation, re-starting the cycle (Losos et al. 2002).

3.4.2. Ovulation and Relationships:

Wide variations in a number of different hormones during the menstrual cycle have been linked to causing several physiological effects, particularly related to levels of estrogen and progesterone (Krejza, Nowacka, Szylak, Bilello & Melhem, 2004). Estrogen levels are highest during the ovulation phase and lowest during the luteal phase, however currently no studies have demonstrated particular causal or correlational links between estrogen and progesterone levels and promiscuous attitudes. A myriad of studies have, however, researched and shown correlations between the ovulation phase of the menstrual cycle and altered preferences for masculine qualities.

Gangestad, Thornhill & Garver-Apgar (2010) showed that relative to during the luteal phase, fertile women expressed a greater emphasis on physical attractiveness of a partner, had greater arousal at the sight or thought of attractive male bodily features, and had greater willingness to engage in sex with attractive men, even ones they didn’t know (sexual opportunism). Gangestad, Thornhill & Garver, (2002) also showed that women ovulating had greater sexual attraction to and fantasy about men other than their primary partner. Gangestad, Garver-Apgar, Simpson, & Cousins (2007) demonstrated that men who appeared to be sexually faithful were less sexually attractive to women who were fertile.

As well as this, ovulating women have been shown to prefer the scent of dominant men (Havlicek, Roberts & Flegr, 2005), masculine faces (Johnson, Hagel, Franklin, Fink & Grammer, 2001), muscular bodies (Little, Jones & Burris, 2007), vocal masculinity (Feinberg, Jones, Law-Smith, Moore, DeBruine & Cornwell, 2006) and taller men (Pawlowski & Jasienska, 2005). Therefore a clear body of evidence exists to show that there is some correlation between phases of the menstrual cycle, and changes in sexual arousal and preference in fertile women.

3.4.3. Summary:

It is clear that a wide body of evidence exists supporting a change in female attraction phenomena according to the phases of the menstrual cycle, as Macleod mentioned in the article. According to the evidence examined, Macleod is correct to say that "women show a shift in preference to men who look more masculine and symmetrical... around the time they are ovulating", in line with the above research. However, as yet no strong evidence exists that supports the statement "women are more likely to fancy a fling around the time they are ovulating". Research completed so far only demonstrates the change in the nature of female attraction towards males, in accordance with the menstrual cycle phases. Whether or not this change in attraction may lead to an increased appreciation for other males outside their relationship, or in fact for their own partner, is still controversial. A number of studies carried out have shown the correlation to go both ways.

3.5. Overall Summary:

Monogamy and promiscuity are certainly shown to be variable over time, according to a wide variety of factors. The factors Macleod examined, testosterone and ovulation, are clearly linked to varying levels of reproductive behaviour and attraction as she mentioned. However, these links are merely correlational, and for both testosterone and the menstrual cycle, no causational explanatory gaps have been filled as to why exactly these correlations exist. As previously mentioned, this opens the pathway for future research to be carried out, and longitudinal studies may one day demonstrate the neural processes responsible for changes in monogamous and promiscuous behaviour according to hormones. To date, the only studies beginning to demonstrate these processes are studies on vasopressin, which is more causationally associated with attachment than any other hormone, and which Macleod fails to mention.


4.1. Target Audience

The life and style section of the Sydney Morning Herald (SMH) is directed mostly toward middle aged men and women, and includes articles on beauty, fashion, diet and fitness, celebrity, home and style, weddings and horoscopes. The article, individually, speaks to men and women in the late 30’s plus, usually of a high working status/education.

Fig. 7: Ratings for number of SMH buyers across classifications (The Newspaper Works, 2012)

4.2. Appropriateness of Pitch

Although the article lacks the technicality of an expertise journal article, it provides a subject of high lifestyle interest and allows everyday readers to get a taste of the research available on this intriguing topic.

Throughout the article Macleod discusses many biological, social and cultural factors that shape different attitudes towards sex. However, after discussing many possibilities on what affects attitudes towards sexual relationships, it is concluded that women are the ones who get pregnant, so there will never be equal attitudes towards sex and relationships.It can thus be inferred that the article is slightly bias towards males being more involved in casual sexual relationships. This stereotype is also reflected in the research that is chosen to be included in the article. Simpson and Gangestad (2007) found that men scored higher on a socio-sexual questionnaire, hence are more prone to casual relationships, also dubbing this an evolutionary by product because males would only have sex to have offspring, not a relationship. Schmitt is then quoted, stating that women’s score rises in their late 30’s, but only because their chance of reproducing is diminishing. Nettle provides a male example of cheating on his partner, not a female, and in the development argument, Belsky uses a male example of how certain levels of attachment effects monogamy. Boothroyd also states that women who were more masculine were more likely to have casual sexual relationships. Although all the research presented was valid and substantiated, the selection showed a bias view point.

4.3. Quality of Information

This article first appeared in New Scientist, a proclaimed world leading weekly magazine in modern science, in November 2008. This magazine is published for "all those men and women who are interested in scientific discovery and in its industrial and social consequences" and 65% of readers either have a Ph.D or M.D level of education (Media centre, 2012).The article, written by Mairi Macleod, was then republished in the Sydney Morning Herald in December 2008 in the Life and Style section. Interestingly, the article was subtlety simplified for the newspaper publishment compared to the science magazine; references and particular arguments were left out. This made the article shorter and easier to read, therefore more accessible to SMH's readership. Macleod is a scientific writer, not a specialised researcher, so it is therefore understandable that she merely collated specific elements of others research to present a case on sexual relationships, rather than provide insight and research of her own. The article lacks direction and structure, finishing with a comment on the future of gender values, not the difference between monogamy and promiscuity. However the information is presented clear and simple, lacking scientific jargon but not content.

The information in the article regarding the influence of testosterone appears to fit in with the current neurological knowledge on the topic. Though much of the research is correlational (and our article had a tendency to imply causation over inferring a correlation), the links made between testosterone levels and promiscuous/monogamous behaviours were not unfounded.

However, there are particular gaps in the article's coverage of the scientific research available on the topic. There was no attempt to use the large amount of neurological literature and knowledge available on other hormones that heavily influence sociosexual behaviour, such as oxytocin and vasopressin. Because the general public is less familiar with these hormones, the article stuck to testosterone as mainly involved, which limited it's ability to give the full picture regarding biological and neurological influences on promiscuity and monogamy.

Other statements were not proven substantially. For example; “several studies have shown that women are more likely to fancy a fling around the time they are ovulating”. This claim is unsubstantiated by research in the article (Gangestad, Thornhill & Garver-Apgar, 2010) which shows high correlations of attraction to masculine male features with the fertile phase of the menstrual cycle. The fertile phase of the menstrual cycle occurs from 5 days up to the ovulation phase. Thus women are more likely to fancy a fling just prior to the time they are ovulating according to this article. Other studies do however show cyclical preferences for masculine features in accordance with the actual ovulating phase, so inconsistency is demonstrated.
On the other hand, some research has proven that women may be more attracted to their own partner during ovulation, reducing promiscuity and enhancing monogamous tendencies. Gangestad, Thornhill & Garver-Apgar (2005) showed that women who had symmetrically-faced partners were more attracted to them whilst ovulating. This is in line with the other research mentioned previously that demonstrates preferences for symmetrical men during ovulation. Thus, it may not be that women "fancy a fling" during certain menstrual phases, but rather just are more attracted to certain types of male features that may or may not already exist in their own partner.

In conclusion, Macleod presents a very intriging topic relevant to SMH's target audience. The neurological context is presented in a clear and simple manner, so everyday readers can relate to the current reserch on this topic. While research chosen to be included in the article may have a male bias towards casual relationships, and important research on other biological aspects of monogamy and promiscuity were left out, the article substantiates the claim that there are biological reasons to our sexual behaviour.


The articles, textbook segments, online resources and papers cited in this research project were gathered primarily using online search techniques, such as through UNSW's database Sirius. Some research was found by hand, and referenced accordingly. Research was selected based on relevancy to the topic after reading the articles/sections in question. The recentness of the research was also taken into account, to ensure that all acquired knowledge on the topic was as up to date as possible. All data used was peer assessed by the other group members for it's appropriateness to the project, to ensure suitability of the research and also encourage inter-group cooperation.

The review comments were extremely useful- our general strengths were that we had chosen an interesting and socially relevant topic, had thorough group cohesion, argued our points well and supported our statements with a good amount of references. Things that were perceived as weaknesses which we changed included improving the general presentation, simplifying sentences in order to make the scientific content easier to understand, include a table of contents, and attempting to make it obvious that our topic was "monogamy vs promiscuity", and not "monogamy vs polygamy" (a typo in our wiki link early on that we have been unable to fix ourselves).

However, there were some suggested improvements that we dismissed, as we felt they were either irrelevant or would not have improved our article:
  • It was said that we should infer more from the articles in the neuroscience context- we decided not to do this, because we thought the neuroscientific context section should be a simple statement of fact and conclusions made by the articles, not subjective inferences based on correlational data.
  • It was suggested to reduce the about of information on testosterone. We dismissed this, because the testosterone literature is vital, as it is the neurological functioning underpinning our topic of monogamy and promiscuity, and one of the focal points of our wiki.
  • Though it was recommended, we decided not to focus hugely on the historical developments regarding monogamy and promiscuity, because (though it would be highly interesting) this information isn't specific to the neurological context.
  • Finally, there were several influences on monogamy and promiscuity mentioned in the article that we did not discuss, and it was suggested that we should. These influences included things such as personality traits and upbrining, i.e. the environmental context of the person. The reason we did not discuss these was because the article didn't talk about any possible neurological foundations for the environmental factors, and we wanted to keep our report strictly neurological. Otherwise we felt our wiki would become too off topic and unfocused.

5.1. References

Burnham, T., Chapman, J., Gray, P., McIntyre, M., Lipson, S., & Ellison, P. (2003). Men in committed, romantic relationships have lower testosterone. Hormones and Behaviour, 44(2), 119-122.

Campbell, N., Reece, J., & Meyers, N. (2008). Biology. Pearson Education Australia PTY LTD.

Clark, A. P. (2004). Self-perceived attractiveness and masculinization predict women's sociosexuality. Evolution and Human Behaviour, 25(2), 113-124.

Feinberg, D. R., Jones, B. C., Law-Smith, M. J., Moore, F. R., DeBruine, L. M. & Cornwell, R. E. (2006). Menstrual cycle, trait estrogen level, and masculinity preferences in the human voice. Hormones and Behavior, 49, 215–222.

Fivizzani, A. J., & Oring, L. W. (1986). Plasma steroid hormones in relation to behavioural sex role reversal in the spotted sandpiper, Actitis macularia. Biology of Reproduction, 35(5), 1195-1201.

Gangestad, S.W., Garver-Apgar, C.E., Simpson, J.A. & Cousins, A.J. (2007). Changes in women's general mate preferences across the ovulatory cycle. Journal of Personality and Social Psychology, 92, 151–163.

Gangestad, S.W. & Thornhill, R. (1998). Menstrual cycle variation in women's preference for the scent of symmetrical men. Proceedings of the Royal Society of London B, 262, 727–733.

Gangestad, S.W., Thornhill, R. & Garver, C.E. (2002). Changes in women's sexual interests and their partners' mate retention tactics across the menstrual cycle: Evidence for shifting conflicts of interest. Proceedings of the Royal Society of London B, 269, 975–982.

Gangestad, S.W., Thornhill, R. & Garver-Apgar, C.E. (2005). Women's sexual interests across the ovulatory cycle depend on primary partner developmental instability. Proceedings of the Royal Society of London B, 272, 2023–2027.

Gangestad, S.W., Thornhill, R. & Garver-Apgar, C.E. (2010). Fertility in the cycle predicts women's interest in sexual opportunism. Evolution and Human Behaviour, 31(6), 400-411.

Gray, H.D. "The Ovum". Anatomy of the human body. Philadelphia: Bartleby.com. (2000). ISBN 1587341026.

Gray, P., Chapman, J., Burnham, T., McIntyre, M., & Lipson, E. P. (2004). Human Male Pair Bonding. Human Nature , 15 (2), 119-131.

Gray, P., Kahlenberg, S., Barrett, E., Lipson, S., & Ellison, P. (2002). Marriage and fatherhood are associated with lower testosterone in males. Evolution and Human Behaviour , 23, 193-201.

Greenberg, J.S., Bruess, C.E. & Conklin, S.C. Exploring the dimensions of human sexuality (3rd ed.). Jones & Bartlett Learning. (2007) pp. 136–137. ISBN 0763745200.

Havlicek, J., Roberts, S.C. & Flegr, J. (2005). Women's preference for dominant male odour: Effects of menstrual cycle and relationship status. Biology Letters, 1, 256–259.

Insel, T. R., & Hulihan, T. J. (1995). A gender-specific mechanism for pair bonding: Oxytocin and partner preference formation in monogamous voles. Behavioural Neuroscience, 109(4), 782-789.

Insel, T. R., Winslow, J. T., Wang, Z. X., Young, L., & Hulihan, T. J. (1995). Oxytocin and the molecular basis of monogamy. Advances in Experimental Medicine and Biology, 395, 227-234.

Johnston, V.S., Hagel, R., Franklin, M., Fink, B. & Grammer, K. (2001). Male facial attractiveness: Evidence for hormone mediated adaptive design. Evolution and Human Behavior, 23, 251–267.

Krejza, J., Nowacka, A., Szylak, A., Bilello, M. & Melhem, L.Y. (2004). Variability of thyroid blood flow Doppler parameters in healthy women. Ultrasound in medicine & biology 30(7), 867–876.

Lentz, G.M., Lobo, R.A., Gershenson, D.M. & Katz, V.L. Comprehensive gynecology. St. Louis: Elsevier Mosby. (2012). ISBN 9780323069861.

Lim, M. M., & Young, L. J. (2004). Vasopressin-dependent neural circuits underlying pair bond formation in the monogamous prairie vole. Neuroscience, 125(1), 35-45.

Little, A.C., Jones, B.C. & Burris, R.P. (2007). Preferences for masculinity in male bodies change across the menstrual cycle. Hormones and Behavior, 51, 633–639.

Losos, J.B., Raven, P.H., Johnson, G.B., Singer, S.R. Biology. New York: McGraw-Hill. (2002). pp. 1207–1209. ISBN 0073031208.

Monogamy. (1989). In Oxford English Dictionary Online (2nd ed.). Retrieved September 22, 2012, from http://www.oed.com

New Scientist. (2012). Media Release, pg 3.

Pawlowski, B. & Jasiénska, J. (2005). Women's preferences for sexual dimorphism in height depend on menstrual cycle phase and expected duration of relationship. Biological Psychology, 70, 38–43.

Promiscuity. (1989). In Oxford English Dictionary Online (2nd ed.). Retrieved September 22, 2012, from http://www.oed.com

Reichard, U. H. (2003). Monogamy: Past and Present. In U. H. Reichard & C. Boesch (Eds.), Monogamy: Mating strategies and partnerships in birds, humans, and other mammals. Cambridge, MA: Cambridge University Press.

The Newspaper Works. (2012). Newspaper Locator. Retrieved from http://www.thenewspaperworks.com.au/newspaper/the-sydney-morning-herald

Van Anders, S. M., & Watson, N. V. (2006). Relationship status and testosterone in North American heterosexual and non-heterosexual men and women: cross-sectional and longitudinal data. Psychoneuroendocrinology, 31(6), 715-723.

Voigt, C., & Goymann, W. (2007). Sex-role reversal is reflected in the brain of African black coucals (Centropus grillii). Developmental Neurobiology, 67, 1560-1573.

Waldherr, M., & Neumann, I. D. (2007). Centrally released oxytocin mediates mating-induced anxiolysis in male rats. PNAS, 104(42), 16681-16684.

Weschler, T. Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. (2002). pp. 359–361. ISBN 0060937645.

Wikipedia. (2012). Digit Ratio. Retrieved from http://en.wikipedia.org/wiki/2D:4D_ratio

Wingfield, J., Hegner, R., Dufty, A., & Ball, G. (1990). The "Challange Hypothesis": Theoretical implications for paterns of testosterone secretion, mating systems and breeding strategies. The American Naturalist , 829-846.

Young, L. J., Winslow, J. T., Nilsen, R., & Insel, T. R. (1997). Species differences in V1a receptor gene expression in monogamous and nonmonogamous voles: Behavoiural consequences. Behavioural Neuroscience, 111(3), 599-605.

5.2. Evidence of Meetings and Progress

5.2.1. Quote by Richard:

Nice Topic - make sure you have enough coordination in writing the project. Approved

5.2.2. Minutes from Meetings:

Meeting to confirm tasks and further discuss project- august 17th

Contribute first information (ie scaffold of information)- august 26th

Group discussion and interaction on Facebook

5.2.3. Group Pictures: