106 CHAPTER FOUR
surges of estrogen, progestin, prolactin, and oxytocin prepare the body for
physical labor. They also prepare the brain and mind for affective labor.
Churchland and Young both argue that oxytocin’s primary social function
is to orient a female toward her offspring so that she is willing to nurse
them, protect them, and generally provide for their well- being. As Young
explains in a Time Magazine interview, “the [oxytocin] molecule was first
involved in the physiological process of birth. With mammals, you’ve got
them needing to nurse and oxytocin is involved in milk ejection. You also
have to transform the mother’s brain so that she focuses her attention on
the baby, so she becomes a mother. Oxytocin is acting both on the body and
the brain to transform her into a mother” (Szalavitz 2012).
According to the “maternalized brain” theory, this transformation be-
gins even before birth, independent of any social interaction with offspring.
It is a multistage process. First, through surges of prolactin and estrogen,
pregnant females are oriented toward a state of maternal expectation; they
become absorbed in preparations for birth and caretaking. Churchland ex-
plains, “In rodents and cats, for example, this causes the pregnant female
to eat more, to prepare a nest for the expected litter, and to find a place
reckoned as safe to give birth” (2011, 33). In humans, Churchland claims,
“females too respond to a ‘nesting’ urge as the time for delivery draws near,
and (as I can personally attest) begin energetically to house- clean and fi-
nalize preparations for the new baby.. .” (33). Next, parturition involves
a significant increase in the density of oxytocin receptors. The peripheral
circulation of oxytocin allows the uterus to contract; the parallel release of
oxytocin in the brain “triggers full maternal behavior, including preoccu-
pation with the infants, suckling, and keeping the infants warm, clean, and
safe” (33). Finally, postnatal interaction builds on this foundation. Like par-
turition, lactation has not only peripheral but also central nervous system
effects. The stimulation of nipples during nursing promotes not only milk
let- down in the mammary glands but also reduced activation in the stress
system of the brain (Young and Alexander 2012, 98). Lactation has “plea-
surable and calming” effects due to the release of oxytocin and dopamine
(Churchland 2011, 34).
Other kinds of maternal- offspring interaction also involve feelings of
pleasure and reward. With a hypothalamus primed by prolactin and estro-
gen, interaction with offspring stimulates the release of oxytocin from the