The role of Oxytocin in parenting: validation of a novel "baby social reward task"

Infant smiling and crying are important signaling behaviors that alert the
caregiver and elicit nurturance and close physical proximity to the caregiver
(Bowlby, 1969; Murray, 1979; Zeifman, 2001). Although these behaviors have
evolved to increase survival and to aid infant development, excessive and
uncontrollable crying might lead to neglecting and abusive parenting and even
infanticide (Lee, Barr, Catherine, & Wicks, 2007; Soltis, 2004).
Although the infant has a profound effect on parents* behavior, parents also
differ in their sensitivity towards their infants* signals resulting in
different caregiving behaviors. Ainsworth, Blehar, Waters, and Wall, (1978)
describe sensitivity as the ability to interpret infant signals correctly and
to respond in an appropriate and prompt way. Previous research has indicated
that some individuals might respond insensitively and more harshly to aversive
infant signals such as crying, as compared to other individuals. Abusive
parents also display increased physiological reactivity towards infant crying
such as a higher heart rate and skin conductance compared to sensitive parents
(Frodi & Lamb, 1980; McCanne & Hagstrom, 1996). Furthermore, they report more
feelings of discomfort and frustration in response to crying infants as
compared to sensitive parents who report more empathic feelings (Crouch,
Skowronski, Milner, & Harris, 2008).

In this study we focus on behavior in response to different infant signals,
including crying as well as smiling. More specifically we investigate the
behavioral differences of an individual towards different infants who are
either perceived as happy and consolable versus infants perceived as distressed
and unresponsive. This is assessed by a computer based task called *the baby
social reward task* specifically designed for the present proposal. Moreover,
the main aim of the study is to explore the effects of oxytocin on adults*
behaviors during the task as oxytocin has been implicated in social affiliation
and parental behaviors. Research from our group has shown that increased levels
of oxytocin induce more sensitive parenting (Naber, Van IJzendoorn, Deschamps,
Engeland, & Bakermans-Kranenburg, 2010). Many other researchers have also shown
plasma oxytocin levels to be associated with parental sensitivity (Feldman et
al., 2010; Gordon, Zagoory-Sharon, Leckman, & Feldman, 2010; Levine,
Zagoory-Sharon, Feldman, & Weller, 2007). However, recent studies have shown
that oxytocin might have a polarizing effect on human behavior. Specifically,
Bartz and colleagues (2010) have demonstrated that individuals with a secure
attachment style reported their parents to be more caring after oxytocin
administration, whereas individuals with an anxious attachment style reported
their parents to be less caring after oxytocin administration as compared to
placebo administration. Similarly, De Dreu and colleagues (2010) suggest a
*tend and defend* effect of oxytocin in altruistic behaviors towards in-group
and out-group members respectively.
To our knowledge, there are no studies showing polarizing effects of oxytocin
on parental behaviors. The present proposal aims to establish whether oxytocin
only has positive effects on parenting or might result in different effects
when the perception about the infants varies from positive (happy and
consolable) to negative (distressed and unresponsive), and how this is related
to participants* affect while taking care of an infant simulator. Additionally,
we also wish to investigate how the effects of oxytocin administration is
modulated by individuals* oxytocin receptor genotype (OXTR GG versus AA/AG) as
this polymorphism has been previously implicated in parental sensitivity
(Bakermans-Kranenburg & Van IJzendoorn, 2008).

Primary Aim:
Modulation of behavioral responses of adults towards infants perceived as happy
and consolable versus distressed and unresponsive, by intranasal oxytocin
administration.

Secondary Aim:
Association between these behaviors with 1) reported feelings of empathy and
aversiveness in response to infant crying and 2) their oxytocin receptor
genotype (GG vs. AA/AG).

Importance of the knowledge to be gained
The proposed study will help us in understanding the complex cognitive and
neurobiological mechanisms underlying parenting behaviors. It will also give us
insight into the interaction of various factors (infant crying and parental
sensitivity differences) which may lead to abusive parenting.

This is a randomized, placebo-controlled, double-blind, between-subjects design
to assess how oxytocin influences individuals* behavior towards happy and
consolable infants versus distressed and inconsolable infants (Baby social
reward task).

The participants will take part in a laboratory session during which subjects
will perform a social baby reward task which will assess their behavior towards
infants considered as happy and consolable versus infants perceived distressed
and unresponsive.

During the session the subjects will take 6 puffs of nasal spray containing 4
IU/ puff of oxytocin (Syntocinon, Novartis), or 6 puffs of a placebo-spray
(NaCl solution). Intranasal oxytocin is widely prescribed in lactating women
and is well tolerated. High doses (> 60 IU) of oxytocin nasal spray may in some
cases lead to headache. Based on the single doses of 24 IU (i.e. 6 puffs, each
containing 4 IU of oxytocin) that will be used during this study and the
effects of oxytocin nasal spray in general, there will be low risk for the
participants in this study.