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Discuss Evolutionary Explanations of Parental Investment

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Discuss Evolutionary Explanations of Parental Investment The evolutionary parental investment theory is the amount put into offspring to promote the survival of their child, born or unborn. One influential explanation of mate selection and human reproductive behaviour is Robert Trivers' parental investment theory (1972). This approach argues that differences between males and females have their origins in the different amount of parental investment made by males and females. The human male's investment in offspring is relatively small. He has large amounts of sperm and remains fertile throughout his life. He is also capable of many matings and the only limit on the number of offspring he can produce is the number of available female partners. Each takes little in terms of time and energy. The best way to maximise his reproductive success is to have many matings with multiple female partners. In contrast, the human female's investment in each offspring is substantial. The gamete she supplies (the ova) is around one hundred times larger than the sperm, and she has a limited supply of these. ...read more.


Trivers' theory helps us to understand the observed differences in sexual jealousy. Men become distressed at sexual betrayal as it means that they may end up investing babies which are not theirs. In contrast, women are more distressed at emotional betrayal as this may lead their partner to move his support and investments to another woman, which may threaten the survival of the woman's offspring. Where trivers' theory is weaker is in the relative rigidity of the behaviours is suggests. Parental investment theory ignores the obvious evidence that not all mating is about long-term relationships and that women, as well as men, clearly engage in short-term relationships, one night stands and affairs. Trivers' theory also tells us little about homosexual relationships which are non-reproductive. For example, it struggles to explain the reluctance of lesbians to engage in short-term, uncommitted sex when the risk of reproduction is not a threat. It also struggles to explain the preference for younger partners that is shown by older gay men. ...read more.


For men it is of crucial importance that the women they select will have good parenting skills otherwise offspring from that relationship may not survive. Even more important is faithfulness as they need to insure that any offspring they might invest in are biologically theirs. For women, it is important to identify a potential partner who will supple resources to offspring and will offer commitment and protection. Sexual strategies theory argues that whilst we are 'hard-wired' to find certain characteristics desirable because they are advantageous in evolutionary terms, 'socially based' characteristics such as outgoing personality of shared interests are also desirable. People are seen as strategists, using their hand of playing cards to secure reproductive success. This explanation also allows room for free will as everything is not seen to be biologically planned out and that we do have some say in who we choose to mate with and for what reasons, making this approach less deterministic. As well, the sexual strategies model is not as nature driven as the parental investment model as nurture is believed to be brought in with the desire of social characteristics in potential mates. ?? ?? ?? ?? Aaron Chamberlain ...read more.

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