Jealousy and Fertility | Study of Delusions

Jealousy and fertility

There is abundant evidence that jealousy and related behaviours in males and females vary during the women menstrual cycle. Levels of jealousy were higher when women were in the fertile phase of their cycle as opposed to the non-fertile phase, regardless of if they were single or not (Cobey 2012).

To test the hypothesis that the ability to provide reflects a man’s potential as a father and creativity reflected ‘good genes’, it was felt that when women were fertile, they would prefer the creative man. Heterosexual women who were not pregnant, breast feeding or on the pill were recruited. They read two paragraphs about males in a business or an art environment. For each, the man was described as either highly creative but poor, or of average intelligence but rich. They were then asked to rate each man as a long- or short-term partner.

Findings were as follows (Haselton 2006)

High fertility was associated with women wanting creative men for short term mating’s
For long term mating’s, there was no relationship between fertility and creativity
In forced choice responses, women who were fertile preferred creative men for short term mating, regardless of whether they were rich or poor. For long term mating’s there was no difference in the males chosen.

This was taken to support the notion that creativity (good physical indicators) was more prised than good dad indicators i.e., wealth, when women were fertile.

Another group of heterosexual women provided daily feedback of their sexual and emotional thoughts for 35 days. Women mated to men rated low in sexual attractiveness were more likely to be attracted to other males, when they were highly fertile. In keeping with this, unattractive men became more jealous where their partners were fertile especially if the females were physically attractive (Haselton 2006b)

Jealousy and mate guarding in women also alters during the menstrual cycle of other women. Female participants read about a potential situation and asked to rate their level of jealousy and guarding behaviours, in response to pictures of women who were either in the low fertile or highly fertile parts of their cycle. One published paper performed three experiments. (Hurst 2016)

The first asked female participants to imagine their partner being with a women shown in a picture who was of low or high fertility. They experienced more jealousy and were more likely to mate guard if they viewed pictures of highly fertile women.
The second experiment did the same but asked for responses if they imagined their partner talking to a flirtatious woman, who was either low or high in fertility. Participants reported more jealousy, mate guarding when they viewed picture of women who were fertile
The third experiment reversed the condition and asked the female participants to imagine that other women were mate guarding and jealous of them. Participants ratings of this happening increased as they themselves were more fertile

Women when fertile are attracted to other males and are more attractive to men. Hence female mate guarding varies across the cycle. Female participants of a study were likely to distance themselves from ovulating women, especially if their own partner is attractive and be less trusting of such women. This may be more pronounced if such women had access to the mates of participants. This distancing may be more likely to occur if the ovulating woman was attractive. This is consistent with attractive males engaging in extra-pair copulations with attractive women who are fertile. Such differential behaviour depending on the attractiveness of other ovulating women, may allow females to benefit from having females’ friends but deter rivals (Krems 2014).

Jealousy also varies during the menstrual cycle, with reported levels of jealousy being higher when women are more fertile, and this may be reduced somewhat when women were on the contraceptive pill. Single women were more likely to show this response, though it was present at a lower level in partnered women (Cobey 2012)

People in relationships were asked to rate four situations based in a bar or library and involving a conversation or kiss between the partner or an opposite sex stranger. Jealousy was higher for the bar when there was kissing or a conversation. The other person’s attractiveness was more important in the bar, although being well-dressed was more important in a conversation (Marelich 2002).

One meta-analyses that look at this question of shifts during the menstrual cycle found various things. Female preferences for male markers of genetic quality were slightly higher in periods of high fertility, mainly in short term relationships. There were many moderators of this relationship, many of which related to study design. When it came to preference for facial symmetry there WAS NO DIFFERENCE between high and low fertile periods. The preference for scents that indicated symmetry was non-significantly higher in the fertile part of the cycle. There was a significant preference for masculine faces in the fertile part. The preference for behavioural dominance in males did not differ across the cycle. When it came cues of genetic fitness in assessing the quality of long-term partners, preferences did not change over the cycle in long- or short-term relationships (Gildersleeve 2014).

Another meta-analysis of changes over the menstrual cycle found more negative results. Here it was found that the preference for masculine, dominant, symmetric, and healthy men did not vary across the menstrual cycle, or over short- or long-term relationships. When specifically looking at measures between the high and low fertile parts of the cycle, there was no difference in preferences for masculine men or a desire to have short term affairs with masculine men. The same was found for preferences for dominant men (Wood 2014)

Parents - Mating behaviours can be influenced by parents, and they may control their daughters more as they invest more in a child. This may prevent unwanted conception and enhancing their chances of a good mate who could provide for the parents. Mothers tend to delay sexual initiation for their daughters and impose more restrictions. When it came to their daughters in one study, parents were more likely to disapprove of some activities, to be more upset by daughters having sex and feel the need to approve of daughter’s mates. Daughters did report less approval from their parent, more paternal disapproval of their mates, more likely to have a curfew and being told what to wear than boys (Perilloux 2008).

Parents may have a set of mating eligibility criteria for their children, e.g., we rate beauty in our mates, but uglier people are not necessarily less acceptable to parents. As babies contain genes from both parents, the inclusive fitness of the grandparents and parents may be in conflict. As parents share fewer genes with the in laws than the offspring, it has been felt that a good mate is more beneficial to the offspring than the in laws. A study was done to see if beauty was rated differently between in laws and children. People were asked to rate characteristics in son / daughter in laws and potential mates. The findings are (Apostolou 2008)

There was no difference in age ratings between son in law / husband and daughter in law / wife in parents and offspring.
Parents preferred son in laws to have resources and older than their daughters. Wanted daughter in laws to be younger than their son.
In terms of a husband, wealth and looks were preferred. In terms of a wife good looks.
In terms of a daughter v son in law similar religious culture was preferred.
Male mate preferences are correlated with parent’s preference for daughter in laws and may rank good looks more so that parents.
Female mate preferences are correlated with parent’s preference for a son in law and also rank good looks higher than parents do.

Jealousy and Culture - One study looked at a Caribbean village where relationships were looser and where men tended to look after genetically related children only. Men spent more time with women who were having menstrual cycles as opposed to those who were pregnant and post-menopausal. They were more antagonistic towards their wives and the men who associated with their wives (Wilson 1995). Other cues to infidelity were analysed to determine what drives people to commit sexual or emotional jealousy. When 204 students were asked to think of a relationship and imagine cues that could indicate partner infidelity, 170 potential cues were identified. A further group of 230 students were asked to imagine a sexual relationship and to see whether the previously identified cues set them up them for sexual or emotional infidelity, resulting in a reduction of cues to 14 significant ones, e.g. displays of affection were felt to indicate sexual infidelity, whereas argumentativeness and anger was felt to indicate emotional infidelity.

Cultural influences can vary the level of mate guarding and may vary with the degree of influence that parents have over which mate is chosen. It was shown that both male and female levels of mate guarding rose as the levels of parental influence over mate choice rose. This study was done using university students who came from several parts of the world. The study was repeated in Argentina using Argentinian citizens and the results were replicated. Age, relationship status / duration and birth order did not affect the outcome (Buunk 2012).

Culturally there may be differences in how jealousy-triggering items are viewed. In a Swedish group, men felt that other females were just as likely to feel that enjoying sex required a loving relationship, while females felt that this applied more to other women rather than males. But in a United States sample people were more likely to believe this to be true (Wiederman 1999).

When Chinese and Americans were asked to rate hurt, jealous and anger on infidelity there were no differences except in American women. Another study showed Chinese men rated levels higher than Chinese women. Men rated higher for content / relieved, homicidal / suicidal, happy and sexual arousal, while women rated higher for nausea / repulsion, depression, undesirable / insecure, helpless / abandoned and anxiety in relation to infidelity. Sexual infidelity rated more highly on hostile / vengeful, shock, nausea / repulsion, humiliated, sexual arousal, homicidal / suicidal and emotional infidelity rate more on undesirable / insecure, depression, helpless, abandoned, blameworthy, tired and forgiving. These results appeared independent of experience with relationships or infidelity. Women described more anger and hurt following sexual infidelity. In response to emotional infidelity, women reported more anger, hurt and jealousy (Shackelford 2000).

A comparison of jealously responses between American and Korean participants found men were more distressed by sexual and women were distressed by emotional infidelity. Men were more distressed if their partner had passionate intercourse, if they imagined their partners using different sexual positions, if their partner had a sexual interest in an ex or with a one-night stand (Buss 1999).

A study of Turkish students found that jealousy was higher in the unmarried, whilst married women were more jealous than married men. For physical and emotional reactions to jealousy, women and the unmarried rated higher and women were more jealous on cognitive measures. Predictors for emotional / cognitive reactions were self-esteem, age and how much we find others attractive. Jealousy was lower with age, longer relationships, greater relationship satisfaction, higher attractiveness of partner and lower self-esteem. Cultures where marriage is valued, and sexuality guarded are associated with higher levels of jealousy (Andaç 2006).

A study of psychotic jealousy in India found that the onset of jealousy was between 30-49 in about half. About half were female or rural dwellers. Also 38% were the eldest in the family, 36% were intermediate and 26% were the youngest. Male sufferers tended to be the eldest and female sufferers tended to be intermediate in age. In terms of the object of the jealousy, 56% were family members (Kala 1981). A similar review of jealousy in 31 Sri Lankan couples, found 15 males and 16 females were jealous, all but two couples were married, and most in the age range 31-40. When people complained that their partners were straying, the word ‘suspicion’ was used (De Silva 1999). The ancient tribe of the Kota from India have a system where a man’s wife is available sexually to his brothers and jealousy is punished (Mandelbaum 1938). The Esan people based in Midwest Nigeria. Most are Christians, poor, and men have multiple wives and partners, with a lot of jealousy amongst the women. They have various practices to reduce the prevalence of violence, etc (Omorodion 1993). If we look back in time there is evidence that severe, possibly unreasonable, jealousy was noticed 2000 years ago (Stein 2011).

The desire for a female partner to be a virgin is found worldwide, but there is no country where females desire male virginity. People tended to favour healthy, intelligent people, with similar political and religious beliefs. Overall women tended to favour financial independence, ambition, status and older age. Men were universally shown to favour younger women and be aware of physical aspects of fertility (Buss 2007). Jealousy levels are affected by our surroundings or culture. Certain behaviours are allowed in some settings and therefore do not elicit jealousy (Marelich 2002). Cultures where casual sexual encounters are acceptable tend not to be too worried about sexual infidelity, as this probably means there is no emotional involvement (Harris 1996). In some South American tribes, we have the ‘partible paternity’ where children have more than 1 biological father, who mated with the mother around conception. It helps the child and mother via provision of extra resources, but this may hinder the father by making the child paternal line even more uncertain (Mesoudi 2007, Wilson 1992).

A 7-nation investigation (Hungary, Ireland, Mexico, Netherlands, Soviet Union, USA and Yugoslavia) investigated the issue of romantic jealousy to see if there were cultural differences, with most of the study participants being students. Results were interpretated in terms of factor loadings and there was a good deal of similarity in ratings around the world. But in Mexico there was more distrust, in Netherlands more people had concerns over their exclusive sexual access to partner. But overall, there was no consistent findings across the countries in the scores, which was taken to mean that there was a cultural difference in the experience of jealousy (Hupka 1985). This was extended by doing the same comparison in German, Poland and USA in 1990 and again there was a lot of variation in the ratings for the experience of jealousy (Hupka 1990).

Worldwide sex outside of marriage is related to income, with a ceiling effect at the $30,000, as well as employment. Men tended to stray more, particularly those aged 55-65. Women more so between 40-45 years. The happier the marriage, the less the chance of infidelity, and this interacted with religious observance. As the age of first marriage increases from 13-23 years, the risk of infidelity dropped, and this may reflect troubled teenagers, e.g., pregnancy, family disapproval (Atkins 2001).

What other criteria do we use to choose mates? A study in Serbia found the most desirable criteria were “sincerity, faithfulness, tenderness, passion, reliability, maturity and intelligence”, moderately desirable are “courage, elegance, attractiveness, thinness, sports talent, strength, thriftiness and dominance” and least desirable were “conceit, selfish, insecurity, aggressiveness, fearfulness and introversion”, with some overlap between the genders (Todosijević 2007).

Violence – From an evolutionary viewpoint, raping the partner may be related to female infidelity as well as male social rules. In terms of maintaining relationships, men have used sexual coercion, especially if they were abusive individuals, but there is no difference in sexual coercion between men who were or were not the dominant one. As one evolutionary function is to prevent the partner being unfaithful, cues of female infidelity may prompt males to engage in mate guarding methods. Evidence suggests that as the risk of female infidelity goes up, so does the risk of male sexual coercion, especially if the male makes accusations. Interestingly, those that had used sexual coercion often had more experiences of female infidelity than those men who did not use sexual coercion. When a group of men in a sexual relationship were asked to assess their partner’s past and future likelihood of infidelity, a multiple regression model found that the presence of female infidelity, scores on controlling behaviour index, and conscientiousness predicted the chances of sexual coercion after controlling for the age of the participants, the age of the partners and the duration of relationship. A further study of women in a sexually committed relationship found scores of male sexual coercion were correlated with women’s reports of male sexual coercion / controlling behaviour / injury, assessment of violence and female infidelity. This study is in keeping with evolutionary theories (of men responding to sperm competition) and social theories of male controlling behaviour (Goetz 2007). When it came to assessments of male coercion, Fertile women rated men as more coercive than non-fertile women, with no association with kindness, faithfulness or commitment (Garver Apgar 2007).

Women may react aggressively upon hearing about sexual infidelity. Also, when they are under a cognitive load women tend to dislike sexual over-emotional infidelity (Bassett 2005). 15% of men and women had suffered violence from a jealous partner, and about half of women felt the trigger for violence was their partner’s sexual jealousy. The risk of violence is higher with anger, frustration, if one is delusional (Mullen 1995). An evolutionary theory of aggression, says it can be precipitated by the need to prevent partners from leaving, or be directed toward same sex sexual rivals or to the female partner (Buss 1997).

Men who suspected their partners of being unfaithful tended to use more sexual coercion, which was related to other mate retention behaviours. About 8% of males had raped their partner at least once. For females who had been in a sexual relationship, those who were more unfaithful suffered more sexual coercion and they noticed more mate retention behaviour. Men were also more likely to under-report, so female estimates are probably more reliable (Goetz 2006).

Some have suggested that when males want to spend resources elsewhere, violence directed towards partners may reduce their mate retention behaviour. Mate retention efforts by the husband may increase if the wife is young, has high reproductive potential and with greater time spent apart. Amongst the Tsimane farmers of Bolivia husbands felt arguments were related to the wife feeling jealous, complaining about their use of money, drinking and work record but arguments relating to the husband’s own jealousy were low. Most of the arguments from the wife concerned their own feelings of jealousy, although husbands may have under-reported arguments. Forty percent of husbands inflicted violence on the wife due to her jealousy.

Less common causes of violence were related to the husband’s use of money, their own jealousy toward the wife, and with the husband diverting resources. A wife’s jealousy often precipitated abuse from their husbands, as well as household decisions, frequency of marital sex, etc. When considering the wife mentioning her husband’s jealousy, such reports were lower the older the wife was. Where a husband had an affair, he was more likely to report his wife was jealous and was more likely to assault her. Violence was higher with a young wife and if the couple had spent a lot of time apart. This was confirmed by the reports of the wife (Stieglitz 2012).

Actual Infidelity - Young students and older non-students who were heterosexual were asked to assessments of jealousy in response to hypothetical situations. Adult participants had more experience of infidelity than college age adults, especially females in both groups. In response to hypothetical situations, there was the expected gender difference with forced choice measures but on continuous measures only females were more distressed by emotional infidelity. Those who experience actual infidelity, there was greater distress for sexual infidelity for both genders and higher distress for the older participants. The authors conclude that the expected gender differential was not seen because age and experience with infidelity modified the responses (Varga 2011). Another study of students found about 35% had been cheated on. For these people there was no gender difference in distress or focus on sexual or emotional infidelity. For females whose partner cheated there was a greater focus, they more relationships and placed importance on sex with the relationship (Harris 2003)

A group of heterosexuals and homosexuals of both genders found about 70% had experience of cheating, with distress slightly greater for emotional infidelity for all groups (Harris 2002). A paper-based study of students in their 20’s found the expected gender differences in response to jealousy when they thought about past experiences of actual infidelity. When repeated using a web-based study very similar results were obtained (Edlund 2006). Another web-based study did not find a gender-based difference on forced choice measures if the participants partners had cheated (Berman 2005). A study of Hawaiian student found those who were cheated on had higher levels of jealousy (Zandbergen 2015)

When relationships break up there can be a variety of behaviours, e.g., just turning up at a partner’s home, leaving phone messages, men may increase the resources given to the partner. But infidelity has been used by people to ‘prepare’ mates for the possibility of one. In a group of people who left or were left themselves (rejecter and the rejectee) some interesting things were found. Female rejectees felt the break-up in terms of protection and felt that repeated attempts to restart the relationship were costly. Male and female rejectees did not differ in the likelihood in having requested sex after the break-up, in their perceived desirability and in their ability to find another mate. They experienced more emotional distress as well as jealousy. Rejecters tried to remain friends with the ex, to try to boost their esteem, to use psychotropics and spend resources in trying to attract another mate. They tended to feel happy bit perceived as cruel. Male rejectors reported losing access to friends, sex and resources while females reported costs such as stalking. More males than females prevented break-up by increasing commitment. Male rejecters engaged in other couplings before the final break-up (Perilloux 2008b)

It was found that 47% of men who did not suffer from infidelity were more distressed by sexual infidelity versus 64% of men who had already been cheated upon (p=0.043). However, there was no difference between women who had and had not been cheated upon when it came to finding sexual infidelity more distressing, but women who had been unfaithful themselves were more likely to find sexual infidelity upsetting compared to women who had not themselves been unfaithful (Sagarin 2003).

Jealousy and Homosexuality - The research into jealousy in the same sex community is more limited than that in the heterosexual community. It would make sense that some of the basic findings about jealousy would be replicated but are there are factors that operate in same sex relationships?

When we look at the experience of jealousy in homosexuals, the results are varied. A look at heterosexuals and homosexuals found that homosexuals were less likely to be jealous and to engage in less mate retention behaviours (Bringle 1995). When looking at heterosexuals, homosexuals, and lesbians, it was found in one study that lesbians were less likely to try and manipulate their partners then gay men or heterosexuals. Though gay men were more likely to use threats (Bevan 2002). Another study found emotional infidelity more distressing for lesbians, gays and heterosexual women, heterosexual males were equally distressed by both infidelities (Sheets 2001)

In Brazil, heterosexual and homosexual people were asked how they would react to their partner having committed sexual or emotional infidelity. Heterosexual males and females were more distressed by sexual infidelity, while the numbers of homosexuals who were distressed on sexual infidelity were between these two. Also, straight women and gay men did not show differences according to whether situations involved attachments, pleasurable sex, and flirting, while straight men and gay women were more upset about sexual infidelity (Souza 2006). Some 1800 individuals from Brazil, Chile and Portugal who were heterosexual, homosexual, or bisexual were asked to imagine their response to infidelity from their partner to either a male or female rival. Generally, participants were more distressed over an emotional relationship if the rival was the same sex as them. Bisexual females more distressed if they imagined a female partner with a male (Valentova 2022)

Amongst heterosexual and homosexual people South California, a greater proportion of heterosexuals were more distressed by sexual infidelity than the homosexual group. Also, heterosexual males, gays and lesbians were more distressed by hypothetical emotional infidelity. However, as some 70% had actual experience with infidelity regardless of gender or orientation, this might explain the results. Although similar percentages of men and women had their relationship ended, it was women that tended to end it (Harris 2002)?

When college students were asked to consider their partner betraying them with a member of either sex, the expected gender-specific reactions were seen. Both men and women were more upset by emotional infidelity than with same sex infidelity. People experienced less jealousy in the same sex condition as opposed to the opposite sex condition (Sagarin 2003). In another study with the same conditions, found that women were more distressed by homosexual infidelity than men with lesbian infidelity. Also, men were upset by their partner being with another man and women were more upset if their male was unfaithful with another male than with another woman. Men were more upset when their partners gave oral sex to another man, while women were more upset if their men gave oral sex to other males, this was replicated when religiosity, sex love marriage associations, erotophobia / phila and eroticisation of gay contact were controlled for. Female partners engaging in lesbian contact were the least likely to arouse jealousy. (Wiederman 1998):

There are interesting cases where the sufferer feels that their partner is having a homosexual relationship. One 36-year-old woman had a 20-year history of believing her husband was having a gay affair. A 43-year-old woman with a strict upbringing, frustrated ambitions, and children that the husband did not want, and after many years of being jealous of her husband settled on feeling that he was having gay affair. This was accompanied by other delusions and perceptual problems (Aldana 2003).

The ‘psychological gender’ as defined by gender schema theory might influence the affect that jealousy has. There are said to be four types of individuals her; Sex-typed individuals process information in line with their gender, Cross-sex-typed that process information in line with opposite gender. Androgynous who process information like both genders and undifferentiated individuals who don’t show efficient processing of sex-typed information. When it comes to scores on the Questionnaire on Emotion of Romantic Jealousy, women were more devastated, tried to save the relationship more, had lower self-esteem and more intense feelings of jealousy. Androgynous were more likely to try to save a relationship and had lower self-esteem then males. General levels of jealousy were highest in females, then Androgynous and then males (Banaszkiewicz 2022)

Though there is still a lot of work to do, there is some evidence that elements of jealousy do vary amongst the LGBTQ community, not forgetting the large degree of overlap.