BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QULAITY 1 Running head: BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QUALITY Does Hormonal Birth Control Disrupt the Assessment of Mate Quality through Kissing? Victoria A. Klimaj, Zachary E. Lawrence, Joseph A. Knutson, Elizabeth A. King, Daniel C. Schaefer, and Francis T. McAndrew Knox College Poster presentation at the annual meeting of the Human Behavior and Evolution Society, Miami, Florida, July, 2013. Corresponding Author: Francis T. McAndrew Department of Psychology Knox College Galesburg, IL, USA, 61401-4999 Email: fmcandre@knox.edu Phone: +1-309-341-7525
BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QULAITY 2 Abstract Twelve blindfolded female college students kissed between four and seven blindfolded male college students for ten seconds. Each kiss was rated as to how attractive the woman believed the man to be and how eager she would be to kiss him again. Afterward, she rated photographs of 20 men (including the men she had kissed) on attractiveness and her eagerness to kiss them. Females who were not using hormonal birth control showed significant positive correlations between the attractiveness of a kiss and attraction to the corresponding man in the photographs. Females on hormonal birth control showed no relationship between the two sets of judgments. The results are discussed in light of the possibility that hormonal birth control disrupts normal female sensitivity to male pheromones. Keywords: kissing, hormonal birth control, assessment of mate quality, pheromones
BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QULAITY 3 Does Hormonal Birth Control Disrupt the Assessment of Mate Quality through Kissing? Kissing is a key mate assessment tactic, especially for women. Women are more likely than men to judge a potential partner based upon a kiss, to lose interest in partners with poor kissing skills, and to respond more strongly to taste and smell factors when deciding whether to continue a kiss (Hughes, Harrison, & Gallup, 2007). Ovulating women are particularly attuned to olfactory cues, as olfactory thresholds are lower during ovulation (Parlee, 1983). Ovulating women are more likely to prefer men with major histocompatibility complex (MHC) dissimilarity and are more sensitive to male pheromones associated with sweat and other substances (Lundström & Olsson, 2005; Thornhill, Chapman, & Gangestad, 2013; Thornhill et al., 2003). Olfactory attraction is positively correlated with indicators of mate quality such as symmetry, masculine facial features, and deep voices (Cornwell, et al., 2004; Gangestad, Thornhill, & Garver-Apgar, 2010; Garver-Apgar, Gangestad, & Thornhill, 2008). Kissing is ideal for accessing olfactory cues as it places the nose in close proximity to areas of the body containing large and numerous sebaceous glands (Nicholson, 1984). The most common form of hormonal birth control (HBC) is the combination pill which targets the hypothalamus and pituitary glands, preventing ovulation by suppressing normal hormonal activity (Speroff & Darney, 2010). There is evidence that olfactory abilities are diminished in women who use HBC (Caruso, et al., 2001), and that sensitivity to male odors (e.g., musk, androsterone, and androstenone) is most strongly affected (Renfro & Hoffmann, 2013). Thus, it may be that HBC impairs the ability of women to effectively use olfactory cues when assessing mate quality and that its use
BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QULAITY 4 undermines the strong convergence usually seen in attraction to different signals of male mate quality. METHOD Participants and Procedure Twelve heterosexual female undergraduate students (five naturally-ovulating, seven on HBC) volunteered in response to a campus-wide email at a liberal arts college in the American Midwest. Participants were screened for illness and were asked not to chew gum, use mouthwash, or smoke for one hour prior to the experimental session. Eight different male undergraduates participated in the kissing portion of the study and received the same screening and instructions as the females. All participants were fully informed about the procedures before volunteering. Twenty male volunteers (including the eight kissing males) were photographed from the shoulders up while wearing a plain dark t-shirt prior to the study. Each female participant was blindfolded and seated alone in a small room. A blindfolded male participant was then led into the room by the female experimenter and seated in a chair next to the female participant. The experimenter gently guided the lips of the two participants together by touching their chins, and they then kissed for exactly ten seconds. They were instructed to kiss as though on a first date. They were not allowed to speak or make any body contact other than the lips; no use of tongues was permitted. At the conclusion of the kiss, the male was guided out of the room and the female (still blindfolded) rated how eager she would be to kiss the man again and how attractive she believed him to be, both on a seven-point scale. The procedure was repeated with different males, with each woman kissing between four and seven men.
BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QULAITY 5 After the kissing was completed, the female was led to a different room and shown photos of 20 different males. Each of the men that she had kissed was in the group, but she was told that the men that she had kissed may or may not be in the photographs. She rated each male photo on attractiveness and on how eager she would be to kiss him using a seven-point scale. Results and Conclusion The unit of analysis was the unique combination of each female kisser with each male she kissed on each of the following measures: the female s judgment of the attractiveness of the male kisser, her eagerness to kiss that male again, her rating of that male s facial attractiveness, and her eagerness to kiss that male based upon his photograph. This resulted in 35 judgments on each variable by women using hormonal birth control (HBC) and 26 judgments on each variable by naturally ovulating women (NOW). T-tests revealed no significant differences (p. >.05) between HBC women versus NOW women on any of the variables, indicating that the groups found the men in general to be equally attractive based upon kisses and faces and that they were equally eager to kiss men. Correlations were run on the four variables separately for the HBC and NOW groups. As one might expect, the attractiveness of the man based upon the kiss was positively correlated with eagerness to kiss him again for both groups (HBC: r(35) =.82, p. <.0001; NOW: r(26) =.86, p. <.0001) as was the facial attractiveness of the man with the female s eagerness to kiss him based upon seeing his face (HBC: r(35) =.86, p. <.0001; NOW: r(26) =.88, p. <.0001). The correlations of interest, however, were between the judgments of attraction based upon kissing and the corresponding judgments
BIRTH CONTROL, KISSING, AND ASSESSMENT OF MATE QULAITY 6 of the same men based upon facial attractiveness. These analyses revealed that NOW exhibited a statistically significant positive correlation between attractiveness based on a kiss with facial attractiveness (r(26) =.40, p. <.05) and with eagerness to kiss based on facial attractiveness (r(26) =.45, p. <.02). Eagerness to kiss a man again based upon his kiss was also correlated with facial attractiveness (r(26) =.49, p. <.01) and with eagerness to kiss based on facial attractiveness (r(26) =.50, p. <.009). Women using HBC on the other hand, showed no significant relationship between any of these variables (values of r(35) =.03, -.12,.16, -.02). These results are consistent with the hypothesis that hormonal birth control may interfere with the ability of females to assess mate quality through kissing in a manner that is consistent with other cues to a male s quality.
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