Outline and evaluate evolutionary theories of parental investment.
Parental Investment is defined as any investment given by a parent that increases the chances of survival for an offspring. PI can include resources, such as food or water, but can also include teaching and protection. The initial investment in a child is greater by the female. This is because the female carries the child, in human terms for nine months, and then spends four to twelve months breast feeding the child. It is also far more difficult to produce an ova than a sperm. This means that women prefer quality over quantity while men, who can afford to be a low investing male with a large number of children, prefer quantity over quality.
These differences in Parental Investment can be explained using the evolutionary explanation of parental investment. The evolutionary theory suggests that because, as in most species, a woman has the greater investment, she uses selection criteria to ensure that she does not choose the wrong mate. As women have only a limited number of offspring, they have more to lose if they choose a low investing partner than a male who is capable of fathering many offspring.
Maternal investment, as stated involves carrying and breastfeeding the child. Further, the difficulty of childbirth has increased in our recent evolutionary history as the size of heads has risen 20%. Paternal investment, according to this theory is often low because men cannot be certain of fatherhood and fear cuckoldry. A woman, who is certain of her motherhood due to internal conception, therefore invests highly.
This theory of parental investment is supported by Buss’s hypothetical scenarios which show that men become most distressed over sexual infidelity. This is because they fear investing in a child that is not their…