Relationships 2

Relationships 2

1. Sex Differences in Parental Investment

   • A01- Why do female mothers invest more? As human evolved there were certain adaptive pressures which lead to the size of the human skull to increase in size. This mean that the birth of a newborn had to happen much earlier in development and therefore children are born much earlier in development and are more vulnerable and immature in comparison to animals. Therefore, newborns are much more dependant on their mothers at this vulnerable stage which increases the investment of females. Babies also have to breastfeed after birth for up to 1 year, therefore mothers not only make a greater prenatal investment but also postnatally.
   • The costs of Maternal Investment- Human females have greater costs associated with the upbringing of their children, specifically in childcare. In our ancestors, nine months of pregnancy would be followed by years of feeding and carrying to ensure the survival of the offspring and thus gave mothers a prolonged commitment to children. This is compared to the minimal costs to the males expressed by Symons as 'a few moments of copulation and a teaspoon of semen'. This hows the difference between the sexes in potential reproductive successes which makes random mating all together more costly for the female.
     • Paternal Investments and Cuckoldry- The way in which males make their investment in females is through providing resources for the child's upbringing and subsequent survival. This means that men are required to protect themselves from the possibility of cuckoldry (investing in offspring that are not their own). Although this is the minimum investment of males, it is quite considerable and this makes males more scared of infidelity by female partners (Miller)
       • Sexual and emotional jealousy- There is a difference in types of jealously evoked in males and females as a result of sexual infidelity. A man with unfaithful mate is more concerned with the possibility of cuckoldry in which they waste resources on offspring that do not carry their genes. The women on the other hand, are concerned with the risk of resources being directed onto another woman and possible offspring. This lead to the evolution of sexual and emotional jealousy (Buss 1995) Sexual jealousy is present in males in which they are more aggravated by the actual sexual act as it can lead to cuckoldry whereas females experience emotional jealousy where they are more worried by the shift in emotional focus and subsequent loss of resources.
     • a02- Extra Marital affair- There is supporting evidence for the greater investment of females that comes from the reasoning behind extra marital affairs. Due to expenses of childrearing, females want to ensure good quality offspring as to make sure that efforts do not go to waste. One of ways women can achieve this is by marrying a resourceful man, but at the same time shopping around for an attractive male (who will possess good genes, but have no resources. Research for this is quite elusive, however there is one study that suggest there is some truth to this point from Baker & Ellis. These researchers found that from a survey of 2700 UK women, it was estimated that up to 14% were a result of extramarital affairs. This therefore depicts that the high maternal investment causes females to look to ensure good offspring which supports this theory.