Q: Any articles you can recommend on maternal nervous system response? When my little guy cries I feel like I can’t hear anything else and like my skin is on fire until I get to him. Love to somehow explain this to my partner.
– Christine S.
A: What you’re referring to is the beginning (or later) stages of mother-infant synchrony. It’s a very common phenomenon in child rearing, though sadly perhaps becoming less common with the types of parenting methods employed in Western cultures these days. In the research, it is generally viewed that infants’ behaviour and mom’s responsiveness to the behaviour help set this pattern of synchronicity up and allow it to continue. Of course, as infants age they also tend to respond more strongly to a mother’s affect, thus finishing the cycle and resulting in mutual synchrony. Why do we care about it?
This synchrony is important to the mother-infant dyad as synchrony early in the relationship is linked to secure attachment later on and vice versa. This was found in two separate studies by Russell Isabella and Jay Belsky. In the first, mother-infant interactions at 1- and 3-months for children who were later classified as securely attached (at one year) were characterized by a larger than expected proportion of synchronous interactions than those who were insecurely attached at a year. The second study was a replication and found the same effects at 3- and 9-months of age, suggesting that the importance of this synchrony to attachment was not a one-off effect. It is worth noting that during the observation period, even the attached groups had more asynchronous interactions than synchronous ones (674 vs. 361 at 1 month); however, these interactions were coded for all forms of behaviour instead of just distress and responsiveness to distress (e.g., looking, vocalizing, sleeping) and other research has clearly shown that it is this responsiveness to distress that is paramount to later attachment. Importantly, the areas in which there were some of the largest differences between the groups on behaviour were when the infant was in distress and crying – at those times, the infants who would grow to be securely attached were more likely to be responded to and soothed than those who would be insecurely attached.
However, none of this reveals the mechanism behind this type of synchrony. Luckily for us there are studies that have examined the stress response found in children and mothers and the degree to which there is a synchronous relationship between them. Research from 3-month-olds has shown that more sensitive mothers show greater cortisol attunement with their infants when they are together. Separation from the mother at this young age seems to result is disattenuation which seems to be the reason why infants cry – they are attempting to get their mother’s attention and reconnect physiologically and behaviourally (and when they are taught to stop crying, this attunement significantly decreases). In fact, in one study, during the infant-mother separation period mothers’ cortisol levels were correlated with their own change in cortisol; that is, mothers who were more sensitive showed a greater distress reaction to being separated from their infant than mothers who were less sensitive. This may lead to a positive cycle in which the stress that results from separation increases attunement and synchrony which helps build bonds and improve the connection between infant and mother which increases sensitivity.
Unfortunately there is no work on the issue of physiological attunement between 3-months of age and 2 years of age, leaving open the question of whether the relationship between parenting and sensitivity affects the development of this attunement. However, at 2-years of age, we see interesting results. In a study of 2- to 4-year olds, children were asked to walk across a balance beam apart from their mothers who were watching on a TV in another room, a novel and potentially challenging task for the child. At younger ages mother-child separation resulted in disattenuation, even for sensitive parents. However, in these older children, mother-child dyads that were characterized by high maternal sensitivity showed a strong attunement to cortisol reactivity to the task (performing for the child, watching for the mother) while less sensitive mothers did not show such an attunement. This was independent of whether or not the child was stressed by the task. In other words, it was not that less sensitive mothers had children who were not stressed by the task – the relationship for sensitive mothers was there across levels of stress for the child.
At some point it seems that this sensitivity and continued attunement become characterized by an even stronger synchrony both behaviourally and physiologically—the idea that attunement and sensitivity feed off each other is supported. But more specifically in response to your question, this research suggests that you may have this strong physiological reaction because your body is producing the same cortisol your child is and thus you are feeling the need to not only dampen your child’s response, but in turn your own. It’s one of those wonderful ways in which we’ve evolved to do what is best all around. But what you are feeling is real and seemingly advantageous to the mother-child relationship into toddlerhood (and probably beyond, though there’s no research into that), even though your physiological feelings (e.g., being on fire) may differ from another mother’s, the experience of needing to get to your child is an evolutionary and biological mechanism that seems to be in place to elicit the type of bonding associated with a securely attached relationship.
Isabella RA, Belsky J, von Eye A. Origins of infant-mother attachment: An examination of interactional synchrony during the infant’s first year. Developmental Psychology 1989; 25: 12-21.
Isabella RA, Belsky J. Interactional synchrony and the origins of infant-mother attachment: A replication study. Child Development 1991; 62: 373-84.
Middlemiss W, Granger DA, Goldberg WA, Nathans L. Asynchrony of mother-infant hypothalamic-pituitary-adrenal axis activity following extinction of infant crying responses induced during the transition to sleep. Early Human Development 2012; 88: 227-32.
Sethre-Hofstad L, Stansbury K, Rice MA. Attunement of maternal and child adrenocortical response to child challenge. Psychoneuroendocrinology 2002; 27: 731-47.
Thompson LA, Trevathan WR. Cortisol reactivity, maternal sensitivity, and learning in 3-month-old infants. Infant Behavior and Development 2008; 31: 92-106.
van den Boom DC. The influence of temperament and mothering on attachment and exploration: An experimental manipulation of sensitive responsiveness among lower-class mothers with irritable infants. Child Development 1994; 65: 1457-77.