Bora tipped me off to Kate of the Anterior Commissure (one of the best science blogs out there currently) who has a very nice post on bonding as it applies to parent-offspring relationships. She says:
This bonding strategy (she argues that it is a visual strategy), reflective of reproductive/maternal adaptations and neuroanatomical phylogeny, may be one of the reasons that, according to Broad et al., in “humans and certain non-human primates…mother-infant bonding [can] occur outside the context of pregnancy and parturition and in the absence of lactation.” That is, our heavy dependence on visual input, plus our relatively complex cognitive capacity (including logical reasoning, judgement and prediction, complex motivational and emotional processing, even morality) inferred by our large cortical mass, suggests that primates and, particularly, humans have developed a phylogenetically advanced strategy for bonding with their offspring that is increasingly liberated from hormonal control.
OK, so aside from knowing what a “phylogenetically advanced strategy” is.. I agree… but she goes on…
If this is the case, parental behavior has become non-hormonally mediated and thus anyone might parent effectively regardless of sex or pregancy history. Which I believe is already firmly the case. Researchers have already documented a number of instances of alloparental behavior, or caregiving by a non-parent; many of these occur outside of hormonal regulation. Just consider what kinds of advantages that would confer to a complex and highly social species, such as our own!
1st- to some maybe being nit-picky, but an important concept that non-scientists frequently confuse- and leads to confusion generally about the value of adaptation. Adaptations are good for individuals, not for the good of the species… Group/species level selection a la Wynne-Edwards has been dismissed as not biologically relevant..
This 1st point leads nicely to my 2nd point.. That from the perspective of the individual, alloparenting is rarely adaptive. There are some good examples where alloparenting IS adaptive via kin selection or reciprocal altruism- but these examples are few and far in between.. The costs almost always outweigh the benefits… Therefore, I’ll propose that the predominate rule governing the provision of parental care is this:
Provide resources to your own offspring, give nothing to others.
Following this, and looking at human behavior- alloparenting is rarely successful.. Look at the effects on families/children/marriages of adoption and step-parenting… Stepchildren are much more likely to be abused, etc. Marriages that involve non-biological children are at a much higher risk for divorce that are other marriages.. In general, and with significant exceptions, human alloparenting is not particularly adaptive….
So, In summary, I do believe that the fact that human bonding seems to form via the visual sensorium rather than from olfaction is important, and certainly higher cognitive abilities supports our potential ability to alloparent, but despite this, alloparenting is not generally adaptive to individuals, and therefore while individuals “might parent effectively regardless of sex or pregnancy history”, this is not usually the case.
I wonder if vision based bonding is adaptive? I’d argue against the alloparenting thing.. Anybody have another idea? I’d wonder if odor or spatial clues became unreliable as a result of a combination of sociality AND small effective population size that limited gene (MHC) diversity…of course this would not hold for non social species…. and the small Ne thing couldn’t be the case for ALL the taxa…Hmmmmm….
7 responses so far ↓
1 Kate // Aug 29, 2007 at 6:51 am
thanks for your thoughts - i linked to this, as i think it brings up some good issues.
to your first point, you’re right and i’ve misspoken - adaptation always benefits the individuals. i’ve inserted a clarification and apologized to richard dawkins
to your second point, that alloparental behavior isn’t adaptive: i agree that there are many instances of poor-quality care given to children that aren’t one’s own, and that the stepfather-abuse phenomenon is, sadly, fairly well-established. but i’d argue that, to many species, care is sufficient; quality care is unnecessary. Francis Champagne’s work (that i’ve blogged about earlier, in my father’s day series) that suggests that quality of caregiving behavior is actually an epigenetic phenomenon, capable of remodeling gene transcription to permanently affect future generations. but aside from this instance, perhaps alloparental care, so long as it’s not detrimental to the offspring, just needs to be present, but not high-quality, in order for the mother to gain benefit.
and, offhand, i can think of two minor benefits, and a major benefit:
1. hypothetically, they’d be receiving at least *some* resources that they wouldn’t otherwise be getting (cases of extreme neglect aside, of course)
2. the possibility that someone already partially invested in your child could assume full caregiving responsibilities, should something happen to you
3. if someone’s watching your kids, you have more time to pursue other reproductive opportunities, produce more offspring, and get your genes out there. which, we can’t argue, is certainly more adaptive (in the pure sense of the word) than investing all your time and energy in your kids. this last point seems most valid to me.
one mystifying bit that i’ll admit that i don’t get. Hrdy has observed alloparental care by non-related primates. what’s in it for them? i think your comments relate this question quite rightly…
2 Anonymous // Aug 29, 2007 at 11:32 am
“Provide resources to your own offspring, give nothing to others.
Following this, and looking at human behavior- alloparenting is rarely successful.. Look at the effects on families/children/marriages of adoption and step-parenting…”
We adoptees have been saying the same thing for years. No one listens to us though.
3 Taryn // Aug 30, 2007 at 10:19 pm
I’ll add a 4th theoretical benefit to Kate’s list, at least as far as humans go -
(4) It feels good to parent. Let’s not allow our evolutionary zeal reduce us to mere conduits of our own genes.
as for this -
…looking at human behavior- alloparenting is rarely successful.. Look at the effects on families/children/marriages of adoption and step-parenting… Stepchildren are much more likely to be abused, etc. Marriages that involve non-biological children are at a much higher risk for divorce that are other marriages.. In general, and with significant exceptions, human alloparenting is not particularly adaptive….
I’ll spare myself a scientist’s critique because I think I understand the intent of this forum and appreciate the informal atmosphere, but this is sloppy at best, pseudo-science at worst, and undoubtedly implies causal relationship for the sake of the authors’ convenience. Yuck!
Just two clicks ago, I was reading an endorsement of sorts from ScienceBlogs.
4 Matt // Aug 31, 2007 at 6:34 am
So Taryn, which of my points do you disagree with??
5 John // Sep 3, 2007 at 12:49 am
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6 Rich Lawler // Sep 4, 2007 at 7:41 pm
An interesting case of adaptive alloparenting is adoption. In some mammals, a mother will adopt an abandoned cub. At first blush, this appears non-adaptive and downright altruistic, but it’s actually a selfish strategy: if you have two of your own cubs and you adopt an unrelated one, you have now cut the chances of one of your own cubs being killed by an infanticidal male by about 33%. Adoption for dilution when the threat of infanticide is high. I’ve been trying to track down the reference to this…any thoughts?
7 AngelaBridget // Jan 10, 2008 at 6:32 pm
Ïðèâåò.! Ñ Íîâûì 2008 ÃÎÄÎÌ.!
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