Males and females differ in the types of
jealousy they are likely to feel and express.
Males have low paternity confidence and so
are likely to be jealous of sexual infidelity.
If his mate had sex with another male he
cannot be sure the offspring is his and carrying
Females are more likely to be jealous of emotional infidelity.
If her mate falls in love with another
woman he is likely to leave her and her
He would take his resources, making it hard to survive.
Because of this she is likely to employ
strategies to prevent her mate from leaving.
A02 - Buss
Found that men are significantly more
likely to make threats of violence towards
males who are perceived to have made
sexual advances towards their mate.
Women are more likely to use verbal
aggression towards potential rivals.
Often target the attractiveness and sexual
conduct of the rival to try and reduce her
attractiveness in the eyes of the male.
Also has the adaptive advantage of no damage to the physical
appearance, crucial if she is to retain and breed with the top males.
Cuckoldry and Sexual Jealousy
Unlike women, men can never be completely
sure they are the father of their child.
Puts them at risk of cuckoldry.
Cuckoldry = The investment of scarce resources into
an offspring that is not your own, meaning the
resources become unavailable to any existing
children, and he is prevented from having any more.
The male adaptive functions of sexual jealously, therefore, would be to
deter the female from sexual infidelity, minimising the risk of cuckoldry.
This may involve aggression (or the threat
of), which if successful, would clearly be an
adaptive function for the male.
Mate retention and Violence
Buss suggested that males have a number of strategies evolved specifically for the purpose of keeping a mate.
These include restricting their partners
autonomy (direct guarding) coupled with
negative inducements in the form of
violence or the threat of violence.
This aggression is adaptive for men as, not only does it reduce the
exposure of their mate to other males, but it acts as a disincentive
for them to be unfaithful as they will be fearful of the consequences.
A02 - Dobash & Dobash
Those who are perceived by their
partner as threatening infidelity through
their behavior (e.g. flirting) are more at
risk of violence that those who are not.
This can be supported by the numerous studies of 'battered women.'
In majority of cases, extreme jealousy was
cited as the reason for the violence.
Infidelity as an Explanation of Human Aggression
A consequence of men's suspicions of their partners infidelity is partner rape.
Camilleri found that sexual
assault of a female by her
partner was directly linked to the
perceived risk of her infidelity.
Shields et al found that female victims of partner rape
were more likely to have engaged in extra-marital sex
than women who had not been raped.
Camilleri et al found that men
convicted of raping their wives were
more likely to have experiences
cuckoldry prior to the offence than men
convicted of non-sexual partner abuse.
Evolutionary theory would explain such extreme
male aggression as adaptive because such
behaviour dissuades the female from repeating
her infidelity and also has the possibility of
making her pregnant which would ensure she
cannot become pregnant by another male.
Violence towards pregnant partners
Sexual infidelity by a woman may
sometimes lead to pregnancy.
From the perspective of her LT mate, if the child is born, he risks cuckoldry.
So, when a woman becomes pregnant with another mans child,
the adaptive functions of aggression and violence towards the
woman would be to terminate the pregnancy.
Eliminating the rivals child and leaving her free to bear his child.
Evolutionary Explanations of Group Display - Warfare
As there are relatively few women in societies compared to men, men have to compete for a mate.
Displays of aggressiveness and bravery in battle are one way to ensure
access to females as females find these characteristics attractive.
As a result, a willingness to engage in
warfare under such circumstances is
adaptive as it enables young men to
demonstrate that they possess
desirable attributes that make
acquisition far more likely.
Leunissen & Van Vugt found that military men have
more sex appeal than there non-military equivalents.
Palmer and Tilley found that male street-gang members
have more sexual partners than non-gang members.
Acquisition of status within the group
Displays of aggression and ferocity by individual warriors in a
group would lead to respect from peers in the group and would
strengthen the bond between the brave males of the group.
Any perception of cowardice would
eradicate the respect held.
High status within the group increases a males chance of being picked
by a female and reduces competition from other men.
As such, acquisition of status via bravery is another
reason why engaging in warfare is adaptive.
Costly displays signal commitment
One of the primary functions of ritual display, such as those
associated with warfare, is to promote group solidarity.
Since warfare is a particularly dangerous form of
group display, those willing to engage in it have
demonstrated a very clear commitment to the
group, and often have physical scars to prove it.
They have maximised their status within the wider group and have shown that they deserve to benefit from the profits of warfare.
This has historically been sexual access to females.