Wednesday, November 22, 2006

Why all mums say baby looks just like daddy

Here is a good (or bad) example of how evolution can `explain' by a `just-so' story, anything and its opposite!

[Graphic: A Touch of Frost's 65 year-old David Jason and daughter Sophie May at six weeks]

First here is a webbed version from London of a story which also appeared recently in my local morning newspaper, about a paper yet to be published in the journal Evolution and Human Behaviour, which "found that mothers claim a paternal resemblance at birth that does not correspond to the actual resemblance":

Why all mums say baby looks just like daddy, The Evening Standard London, 7 November 2006 Cooing over the latest addition to the family, mothers are often quick to remark 'He's got his father's eyes' or 'She's got daddy's hair.' It might seem to be just gentle banter over the baby's looks as the proud new parents celebrate the new arrival. ... But such seemingly innocent comments are in fact a concerted, if subconscious, effort by mummy to convince their partner that he really is the father, according to new research. The findings of a joint study by scientists in England and France show that while many mothers may say their new baby looks like his or her dad, this is simply a plot which has evolved over time to allay male anxiety about paternity. The research, to be published in the journal Evolution and Human Behaviour, contends that if dad sees himself in the baby, it makes him fatherly and more prepared to look after mum and child. ... The new research was conducted by scientists at Sheffield University and Montpellier University in France using a sample of 69 families with a total of 83 children up to the age of six between them. The parents were asked whom their babies and children most resembled. Pictures of the babies and children were then shown to 209 independent judges who were asked to study them for similarities to their parents, and the two sets of results were then compared. All the mothers said boys looked liked their father, and 77 per cent said girls looked like him too. More than eight out of 10 men thought the child took after them. Yet the judges decided half the babies looked like mum, with one in three looking like dad. The report says: "We found that mothers claim a paternal resemblance at birth that does not correspond to the actual resemblance, suggesting possible manipulation of the perception of facial resemblance to increase confidence of paternity." The research found that for newborns, boys and girls actually resemble their mothers more. Girls continue to resemble their mothers as they grow older, while boys begin to resemble their fathers more between the ages of two and three. "The resemblance ascribed by the parents shows that, at birth, mothers ascribe a resemblance to the father, as previously found, although assessment by external judges revealed the opposite," the report says. "These results suggest that facial appearance is a cue for kin recognition between a father and a child." ...

and in fact "for newborns, boys and girls actually resemble their mothers more." This was given an evolutionary explanation as a "possible manipulation [by the mother] of the perception of facial resemblance [to the father] to increase [his] confidence of paternity."

But one of the advantages of my saving science news articles since 1998 is that I have this 2005 New York Times article which reported on two earlier papers, one of which was from the Evolution and Human Behavior journal in 2003, which found the exact opposite, that babies "are more likely to resemble their dads," and this was given "an evolutionary explanation ... A father, unlike a mother, cannot always be sure a baby is his. If he spots a resemblance ... he will know the child is his and will be more likely to protect and care for it":

REALLY? The Claim: Babies Tend to Look Like Their Fathers, The New York Times, A nahad O'Connor, March 22, 2005 THE FACTS It's one of the first questions to cross a new parent's mind. Does the baby look like me? Studies suggest that, for fathers, the answer is usually yes. In 1995, a study in Nature put the question to the test by having 122 people try to match pictures of children they didn't know - at one year, 10 years and 20 years- with photos of their mothers and fathers. The group members correctly paired about half of the infants with their fathers, but their success rate was much lower matching infants and mothers. And matching the 20-year-olds with either parent proved to be just as hard. The authors offered an evolutionary explanation for their findings: the phenomenon is a natural paternity test. A father, unlike a mother, cannot always be sure a baby is his. If he spots a resemblance, the authors argued, he will know the child is his and will be more likely to protect and care for it, benefiting both mother and baby. Another study, published in the journal Evolution and Human Behavior in 2003, seems to support this. The researchers took head shots of a group of people and morphed them with photos of baby faces without the subjects' knowledge. When they presented the subjects with the faces, the men were more likely to indicate they would adopt or spend time with the babies, male and female, who had more of their facial characteristics. The women in the study, however, showed no preference for children with their features. THE BOTTOM LINE Infants are more likely to resemble their dads. ...

So once again, an "evolutionary explanation" can be dreamed up to `explain' one set of facts and then if it is later found that that set of facts was wrong (up to and including the exact opposite), another "evolutionary explanation" can be dreamed up to `explain' the new set of facts as also consistent with natural selection!

When I read that 2005 article it seemed to me to be reasonable that there would be some selective advantage in newborns resembling their father, because presumably that would improve the likelihood of him investing his paternal care in his child. But the fact that "newborns ... actually resemble their mothers more" indicates that there is no actual selective advantage in newborns resembling their father, which in turn indicates that in general men are not overly worried about caring for some other man's child.

Yet this, like adoption (see Eisenberg, E., "The Adoption Paradox," Discover, Vol. 22 No. 1, January 2001), would be, according to Darwinian `selfish-gene' theory, a "double mistake" (my emphasis):

"Mistakes of this sort may, however, occasionally happen in nature. In species that live in herds or troops, an orphaned youngster may be adopted by a strange female, most probably one who has lost her own child. Monkeywatchers sometimes use the word `aunt' for an adopting female. In most cases there is no evidence that she really is an aunt, or indeed any kind of relative: if monkey-watchers were as gene-conscious as they might be, they would not use an important word like `aunt' so uncritically. In most cases we should probably regard adoption, however touching it may seem, as a misfiring of a built-in rule. This is because the generous female is doing her own genes no good by caring for the orphan. She is wasting time and energy which she could be investing in the lives of her own kin, particularly future children of her own. It is presumably a mistake that happens too seldom for natural selection to have `bothered' to change the rule by making the maternal instinct more selective ... There is one example of a mistake which is so extreme that you may prefer to regard it not as a mistake at all, but as evidence against the selfish gene theory. This is the case of bereaved monkey mothers who have been seen to steal a baby from another female, and look after it. I see this as a double mistake, since the adopter not only wastes her own time; she also releases a rival female from the burden of child-rearing, and frees her to have another child more quickly. It seems to me a critical example which deserves some thorough research. We need to know how often it happens; what the average relatedness between adopter and child is likely to be; and what the attitude of the real mother of the child is-it is, after all, to her advantage that her child should be adopted; do mothers deliberately try to deceive naive young females into adopting their children? (It has also been suggested that adopters and baby-snatchers might benefit by gaining valuable practice in the art of child-rearing.)" (Dawkins, R., "The Selfish Gene," [1976], Oxford University Press: Oxford UK, 1989, New edition, p.101-102. Emphasis original)

in that not only is the man's `selfish genes' investing their parental resources into bringing up another man's child, but they are releasing the real father to go off and have more children by some other woman! As Dawkins admits this is indeed "evidence against the selfish gene theory" (as is its absurd prediction that "mothers [should] deliberately try to deceive naive young females" - including "baby-snatchers" - into adopting" or just stealing "their children")!

Dawkins' excuse that such "a mistake that happens too seldom for natural selection to have `bothered' to change the rule by making the maternal" and paternal in this case "instinct more selective" won't wash. As he had already admitted, such a "mistake" is in fact a "double mistake" (my emphasis) and if there was anything that "selfish gene theory" would predict, and would be falsified if the prediction failed, and that is that it would be a very high priority for "natural selection" to equip men so they would not be so easily fooled by a mother's "manipulation of the perception of facial resemblance to increase" their "confidence of paternity" such that it would lead them to bring up another man's child.

That this is not the case is, along with the evidence of the widespread commonality of adoption, as well as men becoming stepfathers of other men's children, is as decisive a refutation of Darwinian `selfish gene' theory, at least for humans, as there could be!

Stephen E. Jones, BSc (Biol).


Genesis 12:1-4. 1The LORD had said to Abram, "Leave your country, your people and your father's household and go to the land I will show you.2"I will make you into a great nation and I will bless you; I will make your name great, and you will be a blessing. 3I will bless those who bless you, and whoever curses you I will curse; and all peoples on earth will be blessed through you." 4So Abram left, as the LORD had told him; and Lot went with him. Abram was seventy-five years old when he set out from Haran.

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