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….