A good mate inspires loyalty : relationship quality moderates an ovulatory phase shift in romantic relationship feelings

Theory and evidence are presented that support the hypothesis that being in a high quality romantic relationship protects women from ovulatory phase increases in negative relationship emotions that may shift their interest toward extra pair men. Relationship status, physical abuse, contribution of resources, satisfaction/commitment, and partner attractiveness were reported by a mixed race community sample of 353 women in a between-subjects design. Fertile women in low quality relationships (e.g., less committed, more abusive) showed more negative, conflicted, and ambivalent as well as less positive relationship feelings relative to both fertile women in high quality relationships and to non-fertile women. Supplementary analysis showed partner attractiveness (PA) was uncorrelated with relationship quality (RQ), and PA also moderated the ovulatory shift such that fertile women paired with attractive men felt better about their relationships than did all other women. Three way interactions (Fertility X RQ X PA) confirmed that RQ and PA are not only distinct components of mate quality but that they also moderate the influence of ovulatory shifts on relationship feelings. Implications for the theories of dual sexuality (Thornhill, 2006) and strategic pluralism (Gangestad & Simpson, 2000) are discussed. Ovulatory Shifts in Relationship Feelings 3 A Good Mate inspires Loyalty; Relationship Quality buffers against an Ovulatory Phase increase in Negative feelings about Romantic Partners Introduction Are women predisposed to cuckold an unattractive mate? Evolutionary models of female sexuality have argued this possibility on the basis of evidence that women prefer “attractive” male attributes during the phase of their menstrual cycles when they are fertile relative to the rest of their cycle (Thornhill, 2006). A pre-ovulatory shift in sexuality and preferred male attributes (Gangestad & Cousins, 2001; Simpson & Lapaglia, 2006) is thought to focus women on the physical attractiveness (a presumed indicator of genetic quality) of a partner during times of high conception risk, in contrast to a focus on the pair-bonding qualities of a partner during the non-fertile phase (Gangestad, Garver-Apgar, Simpson, and Cousins, 2007). However, both theory and empirical research have focused primarily on physical attributes of the male partner, and they typically exclude pair-bonded women (e.g., Gangestad, Simpson, Cousins, GarverApgar, & Christensen, 2004) and ignore the pair-bonding attributes of the male partner. In the only study of ovulatory shifts in relationship functioning, Haselton and Gangestad (2006) tracked 25 pair-bonded women across one menstrual cycle (35 daily reports) and found that women who valued their partner’s attractiveness over his relationship investment reported less extra pair interest and less partner jealousy at fertility relative to other cycle times. Although this finding is consistent with the hypothesis that women are focused on partner attractiveness at fertility and provides evidence that partner attractiveness moderates an ovulatory shift in extra pair interest, the quality of the relationship was not tested. Indexing relationship quality and partner attractiveness as Ovulatory Shifts in Relationship Feelings 4 opposite poles not only fails to distinguish partners who are both attractive and good pair bonders from partners who are only one or the other, but it prevents examination of the relative contributions of relationship quality and partner attractiveness to ovulatory shifts in experience. In this paper we argue that given the importance of male parental investment to women’s reproductive success (Geary, 2000; Geary & Flinn, 2001), the quality of pair bonds must be taken into account in theoretical models and empirical studies of fertility. We therefore argue that ovulatory shifts that focus women’s interest on attractive extra pair men at fertility should be stronger among women with low quality pair bonds. Thus, we begin with a discussion of theoretical models of human reproduction and argue that the quality of a pair bond is an overlooked element of those models (Geary, 2000). Next, we outline an empirical test of the idea that the quality of a pair bond moderates ovulatory shifts in both explicit relationship feelings and implicit emotions which could buffer women from ovulatory increases in negative relationship feelings. The latter are thought to accompany the ovulatory focus on attractiveness of the mate and extra pair mates (Gangestad & Simpson, 2000). We find preliminary evidence to support our model, but also conclude that more research focused on relationship quality in women in long term pair bonds is needed in order to answer questions about the nature of ovulatory shifts in female sexuality. The function of ovulatory shifts and the importance of pair bonding Human fertility was long thought to be concealed, but we now think of ovulation as merely covert (Powlowski, 1999; Havlicek, Dvorakova, Bartos, & Flegr, 2006), because women experience a host of subtle pre-ovulatory (fertile phase) shifts in Ovulatory Shifts in Relationship Feelings 5 sexuality and cognition relative to non-fertile cycle phases. As mentioned, empirical studies support the theory that these shifts function to focus women on pair-bonding during non-fertile phases and on mating during fertility (Thornhill, 2006). A typical focus on pair-bonding is consistent with evidence that male parental investment increases the probability that human offspring will survive and thrive (Geary & Flinn, 2001). However, the ovulatory shift theoretically occurs because a pair-bonded mate may not have the “best” genes available to a given woman, where “best” is defined by enhanced (relative to her current mate) prosperity of the offspring (Williams, 1992). And, given the high cost of each conception for women including a burdensome pregnancy, significant chance of mortality during childbirth, and a prolonged period of expensive provisioning women theoretically seek not only the “best” genes for each pregnancy, but also a stable rearing situation (i.e., a committed relationship; Hrdy, 1999). At the same time, pair-bonded males are typically vigilant against cuckoldry (Geary, 2000), making it costly to the pair bond for women to seek extra-pair mating (Bellis & Baker, 1990). One way a woman can reduce these costs is to engage in extra pair mating only when there is a high probability of conception – that is, when the woman is in the fertile phase of her cycle. Consistent with this, infidelity rates are higher when women are fertile (Bellis & Baker, 1990). Following the introduction of this theoretical perspective, a great deal of research has focused on ovulatory shifts in the attributes women prefer in romantic partners, and more recent research has distinguished between preferences for long term mates vs. short term mates. Although some women engage in short-term mating hoping to extend the liaison into a long-term bond (Regan & Dreyer, 1998) or for material gain (Vigil, et al., Ovulatory Shifts in Relationship Feelings 6 2006), the primary function of short-term mating (for women) is theoretically access to high quality genes (Thornhill, 2006; cf. Hrdy, 2003). Thus, attributes that women prefer in short term mates are correlated with high immune functioning and social success or dominance (Gangestad et al, 2007), which are in turn correlated with human reproductive success (Alexander, 2004). In contrast, women emphasize their preferences for stability, amiability, loyalty, and material success in long-term mates (Buss & Barnes, 1986). In light of these disparate preferences, current theoretical models of mating argue that because women prefer males that display dominance and social success at fertility, women are adapted to cuckold long term mates that do not have attractive attributes with more attractive and dominant males during their fertile phase (e.g., strategic pluralism, Gangestad & Simpson, 2000). In other species, this tendency to cuckold is contingent on mate quality (Møller & Tegelström, 1997). Interestingly, although women value male attractiveness, the most attractive men may not make the best pair bonding partners. Male fitness display is thought to increase with androgen (e.g. testosterone) levels (because only males in good condition can tolerate high testosterone levels; Geary, 2005), and male attractiveness is strongly linked to physical markers of high androgen levels (Grammer et al., 2003; Gangestad & Thornhill, 2003; Dabbs & Mallinger, 1999; etc.). Male attractiveness is also linked to economic success (Mulford, Orbell, Shatto, & Stockard; 1998), suggesting that attractive men have more potential resources to contribute to a family. But high androgen levels are also correlated with elevated reactive aggression (Benderlioglu et al., 2004), higher dominance (Perrett et al., 1998; Mazur & Booth, 1998), and lower paternal and spousal investment behaviors (Fink & Penton-Voak, 2002; Gangestad & Simpson, 2000; Gray et Ovulatory Shifts in Relationship Feelings 7 al, 2002; Puts, 2005). Those correlations suggest that males with high androgen levels (which are strongly linked to physical attractiveness) may be less able to maintain stable pair bonds and be less generous in contributing resources toward offspring relative to their lower androgen counterparts. This in turn implies that male attractiveness is valuable to women because attractiveness is heritable and correlates with reproductive success, and not because attractive men make especially good mates. Good pair bonding protects against cuckoldry To the extent that high pair-bonding ability correlates with reproductive success and is heritable, it should be valued in the same way that physical attractiveness is valued by women (Williams, 1992). Given that the majority of children born to pair-bonded women are in fact sired by their mother’s pair-bonded mate (abou