Biologically speaking, men and women face at least one important difference when raising a child. Due to biological mechanisms, it is virtually impossible for a woman to unknowingly raise a child who is not (genetically) her own. I have never given birth to a child myself, but reliable sources have told that it is impossible to miss and impossible to forget! However, men have no such biological mechanism that insures that the child is their own. Therefore, men face paternity uncertainty, or the possibility of unknowingly raising a child who is not genetically related to themselves. In other words, they could be fooled into raising the child of another man.
Now, men can and do knowingly raise children that aren't their own. Either as a step-father or as an adoptive father. This kind of altruistic care exists, and has positive moral implications. However, from a biological perspective, any care a man gives to a child unrelated to himself usually takes away from care he could give to his own children. To use an extreme example, the perfect altruist who only raises other men's children will pass ZERO copies of his own altruistic genes into the next generation! That's a bad ending from a biological persepctive.
Therefore, men should be more interested in whether a child is theirs (genetically) than women should be. Evolution "solves" current problems in the future, not the present. So if we want to look at current male adaptations, we have to consider past males. And in the past, men didn't have DNA tests to confirm or DNA their paternity in front of a studio audience on Jerry Spring! No, men had to use other cues. One of the most likely cues was the behavior of the mother. However, the infant might have also offered cues. In particular, if two individuals share the same genes/DNA, they should resemble each other. Thus, men should be more concerned with resemblance to infants and children than women. Several studies of parental investment have supported this finding. We conducted several studies asking men and women how interested they were to hypothetically adopt an infant or child based on a facial picture.
We found that men placed a significantly greater emphasis on cues of resemblance when they made their hypothetical adoption decisions (the first comparison on the figure above- Volk & Quinsey, 2002). This supports our prediction, as well as the general hypothesis that men are more interested in cues of paternity certainty than women are interested in cues of maternity certainty. We replicated these results in 2007, finding once more a male-bias towards cues of resemblance. Later, with Dr. Marini and my M.A. student Carolynn Darrell, we found evidence (2010) that the relationship between cues of resemblance and paternal care may be bidirectional - fathers who spent more time with their infants reported a significant increase in their perceptions of resemblance as compared to a control group.
It is important to note that even if men possess such an evolved bias, it does not in any way justify the bias or decisions related to the bias. We firmly believe that any such biased can be changed and/or diminished through sincere care and effort!
Created November 2010