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Parental Investment in Humans

Although the amount of male parental investment is quite variable across different cultures, human males do tend to invest more than just gametes to their offspring (Woodward & Richards 2004).  In some cultures, like the Sambia in Papa New Guinea, males seldom provide any care for babies or children at all, but when boys reach age ten, the males collectively take care of them, while prohibiting females from investing any more parental care (Herdt 1999).  On the other hand, studies of cultures like that of the United States have shown that males invest more in their offspring from birth to adolescence, although not nearly as much as females do (Geary 2000).  In order for males to invest in their offspring, they must have a high degree of certainty that the offspring they are investing in are theirs (Diamond 1992), a high degree of certainty that their investment will improve their offspring’s chance of survival, and opportunities to mate with other females which are not restricted by their parental investment (Geary 2000).

Image from: http://www.theprosperouspeasant.com/2007/12/10/the-risk-of-happiness/

Humans have evolved to ensure that these criteria are fairly well met.  Although perhaps the last one-opportunities to mate with other females-is not traditionally accepted in Western-European culture, studies of hunter gatherers and groups like the Mormons show that opportunities to mate with other females are important and result in increased fitness for males (Diamond 1992).  This is important because heavy male parental investment along with female parental investment is necessary for human children to survive.  Human babies are not born with the necessary motor or mental skills to be able to survive on their own, and need to learn these skills from their parents.  Through most of their childhood and early adolescence, humans need to be provided with food, shelter, and protection, as well as training and socialization so that they can learn to be able to provide such things for themselves and their own future offspring.  As a result, humans have evolved to provide their offspring with far more parental investment from both males than most other animals (Diamond 1992, de Waal 2005).

~ by fknizner on April 14, 2009.


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