For many years, evolutionary psychology has studied interpersonal relationship issues to great depths (DeSteno, Bartlett, Saloey, & Braverman, 2002; Grice & Seely, 2000; Wiedermann & Kendall, 1999). The evolutionary model suggests biological influences as a basis of gender difference, without rejecting social forces as a factor in shaping relationship strategies, especially infidelity (Symons, 1979 cited in Cann, 2001).
Based on such a model the present study hypothesizes, that males have a positive attitude towards sexual infidelity, when placed in the position of the perpetrator i. . when males are to be sexually unfaithful themselves. Females on the other hand are to have a more negative attitude when they are to be placed in the perpetrators position. The study will first discuss the evolutionary hypotheses (Buss, Larsen, Westen, & Semmelroth, 1992) followed by criticism by the alternative analysts (DeSteno & Salovey, 1996; Harris & Christenfeld, 1996) and then suggest a synthesis of the theories by investigating perpetrator attitudes rather than victim distress levels.
Buss (1992, 1996, 1999) and his colleagues have maintained over the years that because of "uncertainty of paternity", but "certainty of maternity", men are likely to become more jealous as a result of a mate's sexual infidelity than a mate's emotional infidelity. Sexual infidelity is predicted to be more distressing for men because it may result in cuckolding and the evolutionary cost of investing in another man's offspring (Sabini & Green, 2004).
Women, on the contrary, may be more distressed by emotional infidelity, as it signals a potential threat to a romantic partner's commitment to the relationship, and therefore, to continued access to crucial material resources and economic stability (Cramer, Manning-Ryan, Johnson & Barbo, 2000). Previous research has demonstrated the difference in distress levels between the two genders by dichotomising infidelity into emotional and sexual infidelity.
Buss et al. (1992) conducted a study where participants were asked, on a forced-choice task, to choose between the two types of infidelity, sexual or emotional, indicating which one would be more distressful if they were to be the victims. They predicted that females were more likely to choose emotional infidelity and males were more likely to choose sexual infidelity by their partners as more distressful.
The initial report resulted in (Buss et al. 1992) 83% of females selecting emotional infidelity as more distressing whereas only 40% males deciding on that option. Apparent sex differences were also replicated using physiological responses (pulse rate, electrodermal response, and electromyographic activity) rather than self reported measures in the same study. Follow up studies were then carried out to replicate the results across cultures. Buunk et al. (1996) presented the two jealousy inducing situations used by Buss et al. (1992) to samples from the United States, Germany and the Netherlands.
The results suggested men were more likely than women to choose sexual infidelity as most upsetting. The difference, as noted by Wiedermann and Kendall (1999), was largest in the U. S. sample and less significant in the other two samples. This cross-cultural study was considered a scrupulous test of evolutionary hypotheses, because the Netherlands is known as being a much more "egalitarian and liberal" society than the U. S. with regard to sexual attitudes and sexual codes of conduct.
The cross-cultural differences were indicative of psychological mechanisms' sensitivity to cultural values, regarding sex roles and code of conduct (Wiedermann & Kendall, 1999). Evidence from China, Germany, Japan, Korea, the Netherlands, Sweden and the United States again confirmed the results from the initial report (see Buss et al. , 1999; Geary, Rumsey, Bow-Thomas, & Hoard, 1995 cited in Cramer, Abraham, Johnson & Manning-Ryan, 2002). The methodology of these studies however, was not flawless.
DeSteno and Salovey (1996) criticised the forced choice method with their alternative analysis, seeing that the two choices are logically related. For example, Harris and Christenfeld (1996) argue that when participants select one of the two choices, they may subconsciously be implying that the other type of infidelity may co-exist. The reported gender differences are based on knowledge men and women have acquired about the relationship between love and sex. In brief, "men think women have sex only when in love and women think men have sex without love".
The gender difference is not based on evolved mating strategies but it is due to the disparity between male and female presumptions regarding a partner's emotional and sexual infidelity (Harris & Christenfeld, 1996). Thus, when a woman learns that her partner has developed an emotional relationship with another person, she is especially anguished as she has actually learned that, if her partner is emotionally unfaithful he is also sexually unfaithful. Sexual unfaithfulness is less distressing as she has learnt that "men often have sex without being in love".
According to Cramer et al. (2002), men relate the infidelities very differently. Men may find sexual unfaithfulness as a prerequisite to emotional unfaithfulness, as this fits in with their perception of how women feel i. e. "women can be in love without having sex". Responding to this discrepancy between the different sexes attitudes as perpetrators and/or as victims, the present research was carried out. This study attempts to look at sexual infidelity through the perpetrators attitude and determine whether the attitude type is related to the gender of the participant.
It demonstrates the same discrepancy between the victims and the perpetrators beliefs. Its purpose is also to test hypotheses regarding gender differences in attitudes towards sexual infidelity derived from an evolutionary perspective and/or the alternative analysis. The participants were put in a hypothetical situation of being in an intimate relationship if they were not already in one. Their attitude towards how acceptable it would be for them to commit sexually adultery was measured on a Likert Scale (Likert, 1932 cited in Langdridge, 2004) with indicative positive or negative statements related to infidelity.
The study was an independent samples design and the variables under investigation were gender and the attitude type towards infidelity. The factor of comparison was the gender of the participant, which was the independent variable, and the attitude (whether positive or negative) was the dependent variable.
The participants (n=60, 30 males and 30 females) were undergraduate students from Liverpool Hope University College. The majority of the opportunity sample was drawn from a campus library. Participation was restricted to individuals between the ages of 18 to 25 to eliminate age as a confounding variable. Prior to completing the survey, participants were told that the study was designed to learn more about monogamy instead of infidelity. They were not informed that the study was specifically interested in possible gender differences in attitudes towards infidelity as the concept itself i.e. infidelity/unfaithfulness may not be particularly socially desirable in contemporary society.
Participants were instructed not to put any identifying information on the questionnaires, which were typically completed in 3-4 minutes. No attempt was made to measure the refusal rate, as participation was voluntary and anonymous. However, it was clear that the majority of participants who were asked to participate did so. Participants were also aware of the voluntary nature of the questionnaire and that they could withdraw from the study at anytime.
After the general introduction, participants were advised to consider the definition of unfaithfulness or infidelity, for the purpose of the study, to mean, "having a sexual relationship outside your current relationship." This was specified because the researcher has focussed on sexual infidelity only. Participants were also asked to "imagine themselves in a hypothetical relationship if they are not already in one." Next, they were asked to specify their age and sex only, as the data needed to be strictly anonymous. Respondents were then briefed on how to indicate their preferences on a Likert scale by means of an example.
The results clearly showed males having a positive preference for unfaithful behaviour in contrast to the females. Therefore, it was concluded that there is a significant difference among males' and females' attitudes towards infidelity when placed in the position of the perpetrator. The evidence for gender differences (consistent with the evolutionary model) continues to accumulate with the results from the present investigation. Males show a more condoning attitude towards sexual infidelity for their personal sexual freedom and females show a less accepting attitude -an attitude which does not condone sexual freedom for them.
Infidelity has always been an important theoretical and practical issue. From an evolutionary perspective, infidelity hints at the diversion of important reproductive resources (Buss et al. 1992; Buss & Shakelford, 1997 cited in Shackelford, LeBlanc & Drass, 2000). From an equity perspective (Walster, Walster & Perscheid, 1978 cited in Schutzwohl & Koch, 2004) infidelity signals inequities and discrimination in a relationship. From an investment model perspective (Rusbult, 1980 cited in Shackelford, LeBlanc & Drass, 2000) infidelity indicates lack of commitment to a relationship. In brief, any theory of romantic relationships places great importance to the issue of infidelity.
However, most of the research on infidelity, to date, has focussed on sex differences in response to emotional and sexual infidelity because of the seriousness of their consequences. For example, across a variety of cultures, male sexual jealousy has been found to be a major cause of serious harm to women, including wife beating and homicide (Daly & Wilson, 1988; Daly, Wilson, & Weghorst, 1982 cited in Cramer, Manning-Ryan, Johnson, & Barbo. 2000).
The present study examined and found support for evolutionary psychological hypotheses about gender differences in sexual psychology. Although no alternative theories have been postulated for these gender differences, some such theories may be formulated post-hoc. Perhaps "sex-differentiated socialisation" may be held accountable for the differences as noted by Shackelford, Buss & Bennett (2002). Researchers supporting other perspectives such as role-theory and socialization-based models have also documented these sex differences in reactions as victims and attitudes as perpetrators of infidelity (Shackelford, LeBlanc & Drass, 2000). As stated earlier, these results cannot rule out an explanation based on socialization differences nonetheless, the biologically based evolutionary model does receive support.
An Undergraduate Sample
The common problems of relying on an undergraduate sample are highlighted by Sears (1986 cited in Sabini and Green, 2004). In addition to those drawbacks (such as "higher cognitive skills" and "less stable peer group relationships than older adults"), there are problems specific to testing this evolutionary hypothesis about infidelity. Firstly, experience with relationships may affect judgement and undergraduate students who make up most of the samples may be relatively naive or inexperienced in this way. This shortage of experience could make it harder to imagine themselves in situations where they are faced with such a dilemma. Secondly, emotional attitudes may be triggered by evolved tendencies of individuals. Undergraduate students, for instance, are typically looking for romantic partners, have not inevitably committed to a single mate, and are less likely to be raising children. Thus, matters of paternity certainty and material security may not be central concerns for undergraduates.
The current study not only looks at undergraduates but also only a single culture and a relatively restricted age range. It is possible that a shift in attitude may occur at a later stage in life. Another clear methodological limitation is the reliance on imagined situations. An important but considerably more complex extension of this work could involve participants who have actually been faced with situations described. It may follow up with what emotions were experienced while being the perpetrator of infidelity and the motivation behind the act. Since self reported measures have their own drawbacks, perhaps physiological tests could be used as did Buss et al. (1992).
Nevertheless, this study has added to the growing body of evolutionary hypotheses. Previous findings have only added to the evolutionary model of mate distress and jealousy cues, by concluding that males are more distressed by their partner's sexual infidelity and females are more distressed by their partner's emotional infidelity (. This novel discrepancy mentioned earlier, is why this research may be significant enough for further investigation. Why are men more intolerant of their partner's sexual infidelity but permit their own adulterous tendencies? Why are women less distressed by sexual infidelity by their partners but accept sexual exclusivity ideals for themselves? This inconsistency has only been identified by this pilot study but will need further exploration if it is to be carried further.
The author would like to extend his gratitude to the fellow researchers, Crisenthiya Clayton, Claire Hamlet, Katrina McCoy, Dilip Perera and Dania Salam, who assisted in designing the questionnaire and collecting the data without whom this study could not have been carried out.