104 CHAPTER FOUR
mous species. An oft- cited reference is Murdoch’s Atlas of World Cultures, in
which only 17 percent of the 563 cultures are listed as having monogamous
kinship structures. Despite this, prairie voles are often treated as a model
for human romantic love (Ophir et al. 2008, 1144). Some researchers argue
that even in nonmonogamous societies, humans are capable of sociosexual
bonding akin to those of prairie voles, and that such bonds are “important
to the physical and mental health of individuals and their children” (Young
et al. 2011, 54). In a review in Frontiers of Neuroendocrinology, Kimberly
Young et al. explain: “Intense attraction between mates, often referred to
as romantic or passionate love, is one of the most powerful forces driving
human social behavior, and often precedes the formation of enduring, se-
lective attachments between sexual partners (i.e., pair bonds). Although
such sociosexual attachments are most prevalent in industrialized cultures
with a monogamous social organization, they occur in nearly all human
societies, regardless of subsistence mode (e.g., pastoralist, agriculturalist,
etc.) or mating strategy (e.g., polygamy and monogamy), and are there-
fore an intrinsic part of human social behavior” (2011, 54). The authors
argue for the functional significance of pair bonding in humans, pointing
to cross- cultural measures of health and longevity of monogamously paired
individuals, as well as offspring of such pairs. In accordance with much of
the literature, they assume pair bonds are heterosexual and reproductive,
and that such bonds confer evolutionary advantages. These assumptions,
which depend on a “specific cultural position” that monogamy is “univer-
sally desirable” (Van Anders et al. 2013, 1115), exclude the range of felt bonds
that might otherwise fall under the description of sociosexual attachments.
This exclusion does not merely limit the relevance of the research but also
constrains the thinking about the neurobiology of attachment even within
reproductive relations, a position I elaborate later.
Maternalizing the Brain
The social neuroscientific explanation of oxytocin as an actant in human
kinships begins in evolutionary terms not with pair bonds but with mother-
infant bonds. Oxytocin is strongly identified with maternal bonding with
offspring. For example, nonhuman animal experiments have explored the
effects of both increasing and blocking oxytocin on females’ interactions
with their offspring. Researchers have chemically blocked oxytocin recep-