Mothers Versus Fathers
In a post-industrial setting, equality between sexes and protection of individual rights suggests that fathers do not have a higher capacity to inflict a cost on their children in order to align them with their will. In particular, fathers as well as mothers control wealth; however, there is still inequality with men controlling more wealth than women (wfathers > wmothers); yet, for the average case, this difference may not be considerable. Also, because children at marriage age are relatively independent from their parents, and they rely more for their protection on social institutions than on their family, the (e) is a relative insignificant factor. Similarly, because individual rights are well protected and children are married relatively old, fathers cannot use the advantage that they have over mothers to inflict a cost on their children through physical force (h). Also, although fathers are overrepresented in social institution, these cannot be employed to inflict a cost on children (i). Mothers, by being more effective manipulators than fathers, have a higher capacity to inflict a psychological manipulation cost on their children (jfathers < jmomers).
Paternal uncertainty translates also in the costs from making compromises in order to get benefits from traits (c x r) to be less for fathers than for mothers. Consequently, fathers can potentially gain more from a mating deal than mothers, as they are less constrained by the cost that it may have on their children. In the light of the fact that parents have a limited capacity to inflict costs to their children, this difference is not of particular importance. We may also consider that technological advancements, such as DNA testing, reduce paternal uncertainty. Even so, the behavioral mechanisms of fathers evolved in a context where such technology was not available, so they may have evolved to behave as if they are uncertain about paternity. For instance, a father may discount more than a mother the cost that an action will have on his children, even if, following a DNA test, he is equally certain with the mother that his children are his own. Furthermore, when children marry, parents are old and effectively out of the mating marker; so, benefits from a marital alliance do not affect the direct reproductive success of fathers more than mothers (ffathers = fmothers). Another reason for this equality is that polygyny is not practiced in post-industrial societies.
In sum, in the post-industrial setting, the converging opportunity cost is low and roughly equal between fathers and mothers, as fathers can, for instance, inflict a higher cost on their children through manipulating their wealth and mothers through psychological manipulation.
Turning now to converging opportunity cost, if children make erroneous choices (k) or fail to attract a mate (l), mothers have potentially more to lose because they are more certain that their children are actually their own so that (oconvergin^fathers < ocon- verging_mothers). Note that, as discussed above, even if modern technology eliminates paternal uncertainty, so that both parents would be equally certain that their children are their own, mothers would behave as they have less uncertainty than fathers. The reason is that technology that eliminates such uncertainty has emerged only recently, while the human mind has been shaped in a context where paternal and maternal uncertainty differed. Accordingly, because in this context we expect the converging opportunity cost to be higher than the diverging opportunity cost, and the former to be bigger for mothers than for fathers while the latter to be roughly equal between the two, the overall opportunity cost for mothers would be higher than the overall opportunity cost for fathers, which predicts that in a pre-industrial context, mothers would be more likely to attempt to control their children’s mating decisions than
fathers (mfathers > mmothers).
One study provided direct evidence in support of this hypothesis. In particular, I asked a sample of Greek-Cypriot parents to indicate their willingness to influence their children’s mate choices (Apostolou, 2011). Mothers indicated a significantly higher willingness than fathers. In addition, participants were also asked to indicate whether their parents had or have been attempting to influence their mate choices. Participants reported that their mothers had or have been attempting to influence their mate choices more than their fathers. Moreover, in one study, I asked Greek- Cypriot parents to indicate their willingness to use 12 manipulation tactics in order to influence their children’s mating decisions (Apostolou, 2013a). I found that for several tactics, mothers indicated a higher willingness than fathers. In a similar study, I asked Greek-Cypriot parents to rate their willingness to use these 12 tactics in order to influence the mate choices of their daughters and sons (Apostolou & Papageorgi, 2014). I found that mothers were more willing than fathers to use manipulation on daughters as well as on sons.