As infants are fully dependent on their parents, correct perception and interpretation of infant signals is crucial for infant survival. It is therefore not surprising that specific brain circuits... Show moreAs infants are fully dependent on their parents, correct perception and interpretation of infant signals is crucial for infant survival. It is therefore not surprising that specific brain circuits and neuroendocrine processes have evolved to perceive infant signals correctly and to respond adequately. However, parents vary in their ability to respond to their infants in a sensitive way and several factors may be involved in parental sensitive responsiveness. One important factor influencing parenting behavior is the neuropeptide oxytocin. Of all the hormones involved in parenting and other social behaviors, oxytocin has received the most interest, as evidenced by the high number of scientific studies over the past decade (Bos, Panksepp, Bluthé, & Honk, 2012; Van IJzendoorn & Bakermans-Kranenburg, 2012). Many studies suggest that oxytocin is related to sensitive parenting (Bakermans-Kranenburg & Van IJzendoorn, 2008; Feldman, Weller, Zagoory-Sharon, & Levine, 2007), although the exact mechanism underlying this positive association is not entirely clear yet. Another factor that influences parenting behavior is adult state of mind with respect to attachment (Van IJzendoorn, 1995). In the current dissertation, the role of oxytocin and adult attachment in parenting is examined with a series of functional magnetic resonance imaging experiments. Show less
In the current thesis we investigate both maternal sensitivity and physiological reactivity to infant crying as potential early indicators of later harsh discipline. In sum, we found that highly... Show moreIn the current thesis we investigate both maternal sensitivity and physiological reactivity to infant crying as potential early indicators of later harsh discipline. In sum, we found that highly sensitive mothers in dyadic interactions with their 3-month old infants showed greater HR reactivity and RSA withdrawal in response to cry sounds when compared to less sensitive mothers. The construct of maternal sensitivity proved to be stable over time, with the same construct underlying observations of maternal sensitivity across various settings. Furthermore, mothers who displayed less sensitive behavior in response to their infants at 3 months were also less sensitive during interaction at 6 months, which in turn predicted more harsh discipline use during the second year after birth. Last, our results showed that mothers who were observed to be harsh with their infants at 12 months showed a stronger sympathetic activation in response to repeated infant crying at 3 months. This seems to suggest that harsh parents are behaviorally as well as physiologically overreactive to negative infant signals. Show less
This is the first behavior genetic study of salivary -amylase (sAA), focusing on genetic and environmental influences on stability and change in sAA during baseline and exposure to infant crying.... Show moreThis is the first behavior genetic study of salivary -amylase (sAA), focusing on genetic and environmental influences on stability and change in sAA during baseline and exposure to infant crying. The sample consisted of 184 adult twin pairs. Although there was significant variation between individuals in basal levels of sAA and in responsivity to infant crying, strong stability in sAA concentrations across conditions was found. Similar genetic mechanisms influenced sAA at baseline and in response to cry sounds (explained variance: 51–62%), accounting for part of the stability in sAA. Unique environmental factors explained the remaining variance in sAA, some of them only emerging in response to the cry sounds, explaining individual differences in the pattern of reactivity. These findings confirm that sAA is sensitive to the effects of potentially stressful stimuli (state variance) and at the same time demonstrate its relative robustness and stability across time and conditions (trait variance). Show less
