Jealousy is defined by Daly, Wilson & Weghorst (1982) as a “state that is aroused by a perceived threat to a valued relationship or position and motivates behaviour aimed at countering the threat”. There is empirical support to suggest that there is sexual differentiation in responses to scenario’s which elicit jealous reactions (Pietrzak, Laird, Stevens & Thompson, 2002). In a study conducted at the Australian National University in 2000, more men than women endorsed sexual infidelity as most distressing. The type of infidelity found more distressing to males and females is explained and justified by the evolutionary hypothesis (EH). It suggests that sex differences have their origins in the evolutionary process and are to be found universally (Buss, Larsen & Westen, 1996). Conversely the double-shot hypothesis (DS) suggests that men and women select the more distressing type of infidelity they think implies the occurrence of the other. Finally proponents of each hypothesis point to results and methodological deficiencies of the other hypothesis to undermine its claims. Although both hypotheses have reason to be believed the latter seems to be displaced by the amount of compelling evidence which suggests that sex differences have their origins in an evolutionary process that results in the different reactions to infidelity shown by men and women.
Historically there have been double standards in society, where societies such as those present in the Far East permitted a husband to take revenge on the perpetrators who adulterated his wife. Although such allowances are generally redundant in the vast majority of societies today, jealousy still remains a paramount social issue (Daly et al, 1982).
From an evolutionary point of view it has been thought that when a man loses the control of the females reproductive capacity, he loses ground to other men. Men who were most frustrated of being unable to control the wife, often accused her of being a whore even when she innocently left the house. Such accusations and consequent denials by the wife may have ultimately culminated in violence. Wilt’s study (1974, cited in Daly et al, 1982) shows jealousy to be the most frequent substantive issue in social conflict homicides. Jealousy has also assumed global proportions, where in England and Wales jealousy it has ranked third behind “quarrels and robbery”. As such, jealousy especially within males can elicit feelings of anger and rage. A study conducted by Pietrzak et al (2002) found that men reported a significantly stronger experience of anger, rage and betrayal while imagining sexual infidelity than emotional infidelity. Such results point to situational differentiation i.e. which type of infidelity troubles someone the most and response differentiation, i.e. how one would respond to a situation of sexual infidelity etc.
Evolutionary psychologists propose an evolutionary hypothesis to justify and explain such findings. At the heart of the evolutionary hypothesis is the assumption that sex differences in the elicitors of jealousy arise as a consequence of the fitness-enhancing abilities of men and women (Buss, Larsen, Westen & Semmelroth, 1992). Fitness refers to the ability of raising offspring to sexual maturity (Daly et al, 1982). Thus when fitness is compromised through infidelity, sexual infidelity is more troublesome for a male than emotional infidelity. For males compromise in paternal probability comes at a cost, where mating effort including time and nuptial gifts are lost.
This may occur with a sexual promiscuous female, where males may risk investing commitment and resources into offspring that are genetically unrelated (Buss et al, 1996). A male can lose honour through his kin which may not be easily or quickly regained, however a woman’s honour can never be regained through immodest behaviour (Daly et al, 1982). Thus it is paramount that a mans wife is not seen as engaging in sexual liaisons with other men. Consequently there is immense pressure for males to defend against cuckoldry. Since humans arguably invest more paternal care in their offspring than other mammal, this pressure should be especially intense (Buss et al, 1992).
Alternatively females risk losing resources, time and investment in their offspring if a male engages in emotional relationships with other females. Thus emotional infidelity will be distressing in monogamous relationships due to lost time and moreso in polygamous relationships where there may be a loss of investment to other wives. Although both sexes will be affected by both types of infidelity, they will be weighted differently by men and women (Buss et al, 1992).
Conversely proponents of the “double-shot” hypothesis (DS) argue that any sex differences shown by males and females are not due to evolved psychological differences but due to the different beliefs of men and women (Harris & Christenfeld, 1996). Men and women are equally upset by each type of infidelity. The crucial difference lies in how much they think each form of infidelity signals the other. Men will find sexual infidelity more distressing since they believe women only have sex when in love. Thus a female does not become sexually promiscuous without some emotional connection.
Women on the other hand may view emotional infidelity as more distressing as they believe men can have sex without love (Harris & Christenfeld, 1996a ). Nannini & Meyers (2000) found that men and women ascribe different motives for their partners disloyalty. Men believe women desire extramarital involvement for greater commitment, while women believe men desire sexual variation as the main motive for disloyalty. These findings lend support for Harris et al’s (1996) claim, that differing interpretations account for any sex difference. Men and women view sexual and emotional infidelity as interrelated. Women may select emotional infidelity as more distressing since they believe emotional infidelity also implies sexual infidelity. The perceptions of the non-independence of these events are affected not by evolution but by socialization, past experience and culture (DeSteno & Salvoney, 1996).
DeSteno et al, (1996) suggest certain methodological deficiencies in the models used by evolutionary psychologists. Firstly, there is a lack of random assignment into the two conditions, where males are separately asked to nominate the more distressful type of infidelity and visa versa for females. Consequently there is less assurance that the other dimensions upon which the individuals vary are balanced. This may lead to misspecification and spurious results. Secondly DeSteno et al (1996) devised a Differential Infidelity Implication (DII) which generates a positive score when people believe emotional infidelity implies sexual infidelity more than the other way round.
Where a zero is generated, it suggests that the participant thought both infidelities equally implied the existence of the other.
Consistent with Harris et al’s (1996) findings, women reported a greater DII score than men. Thus the choice between sexual and emotional infidelity is a false dichotomy, since the reported relationship between sex and the more distressing type of infidelity is rooted in the perceptions of the non-independence of these events. Thirdly DeSteno et al (1996) argues that Buss et al’s study (1992) used a forced choice condition, which only allowed participants to choose the one form of infidelity that troubled them the most, and as such participants had no room to think about the other form of jealousy. Thus the results generated by Buss et al (1992) should be interpreted with caution.
Finally although Buss et al (1992) found significant sex differentiation in forced choice conditions, such results have not been replicable using continuous variables. Other findings also refute evidence for an “evolutionarily derived psychological mechanism underlying choice of infidelity” (DeSteno et al, 1996 p.376). Harris et al (1996) found that women found emotional infidelity more distressing, but males found both types of infidelity equally distressing. It is arguable that if evolution was the antecedent cause for sex differences then males and females should defer in their ratings, which was not found.
Schema’s rather than evolution help interpret situations and women may be responding to two threats. The first threat is interpreted as an explicit emotional threat which implies an implicit sexual threat, thus they respond to more than just one form of transgression (Nannini et al, 2000).
The double-shot hypothesis can also explain cultural similarities. In a study conducted by Harris et al (1996) 75% of Dutch men found emotional infidelity more distressing than sexual infidelity. Thus cultural pressures may be responsible for entire patterns of observed effects, where there is cultural pressure to find emotional infidelity more distressing (DeSteno et al. 1996). Proponents of the DS may conclude that the different beliefs of men and women may be moderated by socialization, schema’s and cultural pressures which may lead to sex differences, if any.
However if beliefs were causally responsible for sex differences in reactions to which type of infidelity troubles someone the most, then anything sex linked, e.g. height, index-finger length could also causally be responsible for sex differences in reactions (Buss et al, 1996). Such generalization certainly undermines the credibility of a belief based hypothesis, where any imaginable physiological feature of the human body can be responsible for sex differences in reactions. Where the EH is domain specific in that it contains specific design features of the psychological mechanisms of each sex, DS is domain general where it suggests that beliefs drive emotional distress (Buss, Shackleford, Kirkpatrick, Choe, Lim, Hasegawa H, Hasegawa T & Bennett, 1999).
Buss et al (1999) attempted to refute the claims made by DeSteno et al (1996) concerning methodological deficiencies. Several conceptual problems with DS were raised. These included, why DS failed to account for why males and females differ in their beliefs i.e. do parents exert any influence in forming the beliefs of their children. Geary, Rumsey, Bow-Thomas & Hoard (1995) found that family constellation, perceived parental warmth, nor previous sexual experience was consistently related to jealousy status in either China or the USA.
Furthermore DS fails to specify whether sex differences occur in the minds of men and women which may lead to sex differences, or in the object of belief which may lead to shared reactions. Buss et al’s (1999) research contained 4 studies, the first of which used a forced-choice condition earlier criticized by DeSteno et al (1996). Buss et al (1999) contend that forced-choice conditions serve an important methodological function as Likhert type rating scales are prone to “ceiling effects”, when ratings of the magnitude of upset are measured.
The first study supported the EH with men choosing sexual infidelity as most distressful. Proponents of the DS argue that it was impossible for participants to consider one type of infidelity without the other. However in daily life one can occur without the other e.g. sex without emotional involvement or a “one-night stand”.
Study 2 asked participants to rate which type of infidelity would be most distressing given both types and certain dilemmas, and 65% of men found sexual infidelity more distressing compared to 13% of women. Thirdly logistic multiple regressions built on DeSteno et al’s (1996) study which was not fully crossed. In their research men judged the conditional probabilities for sexual and emotional infidelities for women and the process was repeated by women for men.
However men did not judge the probabilities for other men and the same applied for women. A revamped test, suggested sex differences are found in the objects of the beliefs and not in the beliefs contained in the minds of men and women. Men and women share the same belief that men will find it easier to have sex without emotional involvement.
Finally cross-cultural tests assessing reactions from Korean and Japanese samples found a clear difference in reactions with 47% of Korean men compared to 27% of women reporting sexual infidelity to be the most distressful. Similarly in 4 of the 5 tests carried out on the Japanese sample sex differences were evident.. Although such sex differences are evident across cultures the expression of sexual jealousy might be facultative (Geary et al, 1995). Geary et al (1995) found that there was a larger proportion of sexually jealous males and females in the USA than in China where sexual activity is formally more constrained. Conclusively large sex differences were discovered in Buss et al’s (1999) research despite what tests were conducted, how they were worded or their methodological structure.
The evolutionary hypothesis strongly supports the 2000 research conducted at the Australian National University, where more men than women endorsed sexual infidelity as most distressing. The evolutionary hypothesis suggests that these two kinds of infidelity are weighted differently by men and women because of the different adaptive problems they have faced over human evolutionary history (Buss et al, 1992). It has been realized through evolution that it is less detrimental for a man to have extramarital sexual encounters than it is for a woman. Although it is more detrimental for a man to become emotionally involved with other women than it is for a woman to become emotionally involved with men. Although both the evolutionary and double-shot hypothesis are in agreement as they both correlate to sex, sex differences in beliefs are anchored in conditional probabilities which have their origins in the evolutionary process. Finally the methodological deficiencies criticized by DeSteno et al (1996) have been exhaustively countered by the extensive study carried out by Buss et al (1996) which has accrued a lot of support.