Ovulating Female Preferences to Male Odors in Correlation to Testosterone Levels
Stephanie Cao, Dennis Kephart and Jenna Merrell
Department of Biological Science
Saddleback College
Mission Viejo, CA 92692
Abstract[SZ1]
Evidence suggests that female sexual preference changes throughout the various stages of their menstrual cycle.Their olfactory senses are more sensitive during the ovulation stage. In males, the level of testosterone and pheromone levels are typically directly proportional. This study therefore predicts that an ovulating female’s olfactory preferences would favora male scent that is higher in testosterone compared to non-ovulating females. Females were asked which phase of their menstrual cycle they were currently in as well as their age, and whether they were on birth controlor not[SZ2]. They then inhaled and chose the most attractive scent out of fourteen t-shirts worn by different males over a period of one night cycle (eight hours). After a one-tailed unpaired t-test was run, results indicated that preference varied greatly in range(testosterone range? Female preference range?) and showed that there was no significant difference(“difference”=two-tailed “direction”=one-tailed rewrite sentence to suggest one-tailed test. Possible revision: “After a one-tailed unpaired t-test was run, results indicated that the scent preference of ovulating females for high testosterone was not significantly higher than the scent preference of non-ovulating females”)in ovulating and non-ovulating females’ scent preference in relationship to testosterone level(p=0.133662).
Introduction[SZ3]
Females have been shown to have a heightened sense of smell when they are ovulating. Though humans are much less sensitive at perceiving smells compared to other mammals, Lord and Kasprzak’s (1989) study shows that humans are in fact able to distinguish gender based off(on) scent alone. This is most likely due to the differences in pheromoneslevels.During a females’ most fertile period, it has been found that their extra-pair copulations are typically occurring, according to Gangestad and Thornhill’s study done in 1998.(The order of this sentence is a bit confusing, maybe try: “According to Gangestad and Thornhill’s study in 1998, female extra pair copulations typically occur during the females’ most fertile period.”)[SZ4]It has also been found that the male testosterone level has been shown to be(is)directly proportional to his male pheromone production (Iwata et al, 1999). A similar study found that certain molecules can act as pheromones and(that) are used in mate selection, signaling gender, reproductive status as well as competitive ability (Brennan and Kendrick, 2006). It has been shown that males can smell when a female is ovulating as nature’s way of promoting reproduction (Kuukasjarvi et al, 2003). This particular study, however, will see if(test whether) females prefer a smell(scent) higher in testosterone as a way of insuring “strong” offspring. This could potentially help society further understand the role of scent in mate selection.
Methods[SZ5]
Fourteen males between the ages(in the age range) of 18 and(to) 25 years and twenty menstruating females between the ages(in the age range) of 18 and(to) 50 [SZ6]were used in this study. Subjects were all within the Mission Viejo, California area. All data were collected between 8 November and 27 November 2013 either in the homes of the participants or at Saddleback College. Male participants were approached and asked to be in the study ahead of time (maybe use “prior to the experiment”or a more direct period of time before the experiment like, “one week before the experiment”[SZ7]). When an agreement was reached, male participants were divided into two groups of seven to test over the weekend of 8 November (for the first group?) or 15 November for the second group. Over their respective testing weekend, male subjects were asked to choose one night to shower before bed using Cetaphil brand unscented soap, drool into a Salimetrics collection device, place the vial in the freezer, and then sleep a minimum of eight hours in a Fruit of the Loom brand plain white t-shirt provided on a sheet washed in Purex brand unscented detergent. Male subjects were asked to drool into a separate vial in the morning and return the shirt (in a medium-sized Ziplock bag), sheet and frozen saliva samples. All bags and spit vials were labeled with the participant’snumber of 1-7 followed by an “A” if in the first group and(or) “B” if in the second group. They were also asked to fill out a questionnaire asking their age and an approximate number of hours they work out in a week.
Female volunteers were asked to fill out a brief questionnaire asking their age, whether or not they are or have recently been on birth control, if their periods are “regular” and where they are in their menstrual cycle. They were then asked to smell each of the seven shirts from that(the) testing period by cupping the opening of the bag over their nose and inhaling deeply. On the questionnaire they were to check the box under the number shirt they most preferred.
On 22 November all spit samples were analyzed with a Salimetrics testing kit [SZ8]for testosterone in the Saddleback College biology laboratory and each male participant was given a numerical testosterone level for both their morning and night samples. These two values were averaged. Data were input into MS Excel (Microsoft Corporation, Redmond, Washington) in terms of whether the female was ovulating or not and what the numerical testosterone level was of the smell she most preferred. A one-tailed, unpaired t-test was run comparing the preferred testosterone levels of the non-ovulating versus(to)those of the ovulating females.
Results[SZ9]
When a one-tailed, unpaired t-test was run, the results showed no significant increase in (that the)ovulating females’ testosterone level preference (was not significantly higher than) over that of non-ovulating females (p=0.133662). Males’ average testosterone levels ranged from 52.18 to 219.41[SZ10](units?), with a group average of 124.95(units?). As shown in Figure 1 below, three out of the fourteen males that were tied for the most(highest) number of votes had testosterone levels of 56.49, 79.03, and 219.41(units?).
Figure 1. Number of preference votes of(from) both ovulating and non-ovulating females for each of our(the) fourteen males’ testosterone levels. Preference (of testosterone range) varied greatly(.)in rangeand there was no significant difference [SZ11]in ovulating and non-ovulating females’ preference in relationship to testosterone level(The ovulating females’ preferred testosterone level was not significantly higher than the non-ovulating females’ preferred testosterone level) (p=0.133662).
This showed that not only did many females (regardless of their current menstrual phase) gravitate towards the same few shirts, but that testosterone level did not play a factor as these values vary greatly in range. One observation worth noting, however, is that out of the seven females surveyed for the B group, the five that were ovulating all preferred the shirt with a testosterone level of 56.49 (units?)and the two non-ovulating preferred various others. This shirt was significantly preferred by ovulating females only.
Discussion[SZ12]
While it was predicted that ovulating females would overall prefer a higher testosterone level than non-ovulating females, results were inconclusive. Past studies, such as Live Science’s (2013) study, have shown that females do tend to prefer a scent higher in testosterone when ovulating, however there are so many factors that take play(effect this experiment, that it is) and make itdifficult to repeat these results. Their study also entailed thatthe male volunteers wearing the shirts for two consecutive nights, whereas this particular study only had them wear shirts for one eight-hour night period. This might have not been a sufficient time for the natural odor to be fully absorbed.
In a study involving Mediterranean fruit flies(Shelly et. al, 2007), Ceratitis capitata, an experiment was done on(compared)mating choice and success based upon male scent. The researchers monitored the female attraction to exposed and non-exposed males to plant structures or essential oils. The “perfume effect” used did not have the effect the researchers were hoping on(for). Instead, the attraction was based on olfactory differences. This experiment concluded that mating is done through an external phenomenon (possibly alteration of cuticular scent) rather than through internal processing (pheromone synthesis). In the current study, while researchers tried to minimize these “external” scents by having males shower with unscented soap and sleep on unscented sheets, they could have possibly played a factor and affected the results.
Literature Cited[SZ13]
Brennan, Peter A. and Keith M Kendrick. 2006. Mammalian social odours: Attraction and individual recognition. Philosophical Transaction of the Royal Society B 361: 2061-2078.
Gangestad, Steven W. and Randy Thornhill. 1998. Menstrual cycle variation in women’s preferences for the scent of symmetrical men. Proceedings of the Royal SocietyB 265 927-933.
Iwata, E., Y. Wakabayashi, Y. Kakuma, T. Kikusui, Y. Takeuchi, and Y. Mori. 1999. Testosterone-dependent primer pheromone in the sebaceous gland of male goat. Biology of Reproduction 62: 806-810
Kuukasjarvi, Seppo, C.J. Peter Eriksson, Esa Koskela, Tapio Mappes, Kari Nissinen, and Markus J. Rantala. 2006. Attractiveness of women’s body odors over the menstrual cycle: The role of oral contraceptives and receiver sex. Behavioral Ecology 15: 579-584.
Lewis, Tanya. 2013. Scent of a man: Woman can sniff out a hot guy. (date)Live Science Journal 12: 115-117
Lord, Thomas and Mary Kasprzak. 1989. Identification of self through olfaction. Perceptual and Motor Skills 69: 219-224.
Shelly, Todd E., James Edu, Elaine Pahio, and Jon Nishimoto. 2007. Scented males and
choosy females: Does male odor influence female mate choice in the mediterranean fruit fly? Journal of Chemical Ecology 33: 2308-2324.
*NEED AT LEAST 10 SOURCES (right now you only have 7 sources)*[SZ14]
Review Form
Department of Biological Sciences
SaddlebackCollege, Mission Viejo, CA92692
Author (s):_Stephanie Cao, Dennis Kephart and Jenna Merrell_
Title: Ovulating Female Preferences to Male Odors in Correlation to Testosterone Levels_
Summary
Summarize the paper succinctly and dispassionately. Do not criticize here, just show that you understood the paper.
The experimenters researched that women have an elevated sense of smell during menstruation and, because pheromone and testosterone levels in men are directly related, it was hypothesized that menstruating females will prefer the scent of men with a higher testosterone level in comparison to the scent preferences of non-ovulating females. The male subjects drooled into a Salimetrics collection device before and after sleeping at least eight hours in their clean, unscented shirts and sheets. The shirts were used for the odor rating and the Salimetrics kits were used to determine the testosterone levels of the male subjects. Female subjects were given a questionnaire and they rated the odor of the shirts. Both ovulating and non-ovulating females preferred the scents of three male shirts equally even though the three preferred males had very different testosterone levels. Based on a one-tailed unpaired t-test, the menstruating females did not prefer the scent of men with higher testosterone levels more than non-menstruating females. These results were explained by the possibility that external scents, such as “cuticular scent,” rather than internal scents, such as pheromones, could have effected female preferences. On the other hand, a similar study suggested a significant correlation between ovulating female scent preference and high testosterone levels, this study could have had similar results if the male subjects had spent more time in the shirts (with an exception to the B group).
General Comments
Generally explain the paper’s strengths and weaknesses and whether they are serious, or important to our current state of knowledge.
Overall, this was a very good paper. In general, the paper was easy to understand and sufficiently descriptive. I think the biggest issue was that there are not enough sources included in the paper (only seven out of the minimum of ten).So, get some more sources and add more to your introduction and discussion because you don’t to lose a bunch of points for missing three sources. In the methods, there should be a more in depth description of how the Salimetrics test kit was used and how the test kit works. In the results, the figure caption suggested a two-tailed rather than one-tailed t-test (as did the abstract). Otherwise, there were a couple, format discrepancies in terms of the headers, capitalizing in the Literature Cited, etc. which would be easy to fix but should be addressed. Also, some of the sentence format was a bit confusing so I offered some suggestions to rephrase the same ideas in a way that might flow a bit better. Otherwise, I thought this was a good paper without many major issues.
Technical Criticism
Review technical issues, organization and clarity. Provide a table of typographical errors, grammatical errors, and minor textual problems. It's not the reviewer's job to copy Edit the paper, mark the manuscript.
This paper was a final versionThis paper was a rough draft
Suggestion Key:
Format Revision
Suggested Revisions
(Suggestions on paper)
1.)Remove “Abstract” Heading
2.)“or not” is implied by the word “whether” earlier in the sentence
3.)Center Heading
4.) The order of this sentence is a bit confusing, maybe try: “According to Gangestad and Thornhill’s study in 1998, female extra pair copulations typically occur during the females’ most fertile period.”
5.) Center Heading
6.)Side note for possible future studies: the age range of the female test subjects is much larger than that of your male subjects… maybe that could have been another variable factor of the experiment?-possible topic to add to discussion?
7.)maybe use “prior to the experiment” or a more direct period of time before the experiment like, “one week before the experiment”
8.)Maybe add more detail about how you used the Salimetrics test (especially because you guys went into more detail on the salimetrics method in your presentation and it seemed like Teh wanted more detail on Salimetrics in terms of what you did and how it worked)
9.)Center Heading
10.)Need to include units for your numerical values
11.)one-tailed t-test measures direction, not difference
12.)Center Heading
13.)Center Heading and rename from “References” as “Literature Cited”
14.)NEED AT LEAST 10 SOURCES (right now you only have 7 sources)
Recommendation
This paper should be published as is
This paper should be published with revision
This paper should not be published
1
1.)[SZ1]Remove “Abstract” Heading
[SZ2]2.) “or not” is implied by the word “whether” earlier in the sentence
[SZ3]3.) Center Heading
[SZ4]4.) The order of this sentence is a bit confusing, maybe try: “According to Gangestad and Thornhill’s study in 1998, female extra pair copulations typically occur during the females’ most fertile period.”
[SZ5]5.) Center Heading
[SZ6]6.) Side note for possible future studies: the age range of the female test subjects is much larger than that of your male subjects… maybe that could have been another variable factor of the experiment?-possible topic to add to discussion?
[SZ7]7.) maybe use “prior to the experiment” or a more direct period of time before the experiment like, “one week before the experiment”
[SZ8]8.) Maybe add more detail about how you used the Salimetrics test (especially because you guys went into more detail on the salimetrics method in your presentation and it seemed like Teh wanted more detail on Salimetrics in terms of what you did and how it worked)
[SZ9]9.) Center Heading
[SZ10]10.) Need to include units for your numerical values
[SZ11]11.) one-tailed t-test measures direction, not difference
[SZ12]12.) Center Heading
[SZ13]13.) Center Heading and rename from “References” as “Literature Cited”
[SZ14]14.) *****NEED AT LEAST 10 SOURCES (right now you only have 7 sources)******