Primordial soup to nuts: are some men naturally selected to be better dads?

Children are the future. So “why do some men choose not to invest in their children?” This was the question that Dr. James Rilling set out to answer over the last few years. Dr. Rilling is the head of the Laboratory for Darwinian Neuroscience in the Anthropology Department at Emory University and states one of the lab’s aims is “exploring the neural basis of human social cognition and behavior, particularly those aspects that have been under strong evolutionary selection pressure.” But are absent fathers the result of natural selection?

In the last half-century, the basic structure of American families has been changing. Within two-parent households, fathers are spending more time with their children than they used to as more mothers work outside the home. However, there are also many more single mothers raising children without any paternal help and roughly half of all American children are raised by a single parent at some point during childhood [1].

These changes have occurred far too rapidly to be the result of natural selection, but this trend compels additional study into the factors underlying paternal commitment. It is not known if there may in fact be an evolutionary explanation for why some men are more committed fathers than others. More to the point, do biological differences between men influence behavioral variation? Life History Theory posits that natural selection shapes the allocation of finite resources toward aspects of growth, survivorship, and reproduction. Within reproduction, there is arguably a trade-off in this zero-sum game between parenting and mating activities, and natural selection shapes phenotypes to support optimal strategies.

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