It is heartening then, to see the results of the recent randomized controlled trial by Gradisar et al. in this month’s Pediatrics: 1) confirmation that behavioral sleep training is effective in addressing infant sleep concerns, and 2) that neither graduated extinction, or it’s less daunting sibling bedtime fading, were associated with elevated cortisol or disordered attachment styles.
In hindsight, perhaps we should be so surprised at this result. After all, while disruption of attachment is a valid concern, that the process of sleep training alone should disrupt the process in isolation, takes too simplistic a view of the formation of attachment.
L. Alan Sroufe and colleagues provided an excellent overview of attachment in this Journal back in 2003 (link below). “Attachment,” they quote, “refers to the special emotional bond that infants develop with their caregivers during the first year of life.” “Secure attachment,” they continue “is reflected in the infant’s active use and confidence in the caregiver to regulate emotion.” While these introductory statements, may elicit potential concerns about active ignoring of the infant during extinction procedures, it is important to emphasize that sleep and sleep training represents only one, of hundreds of daily interactions between an infant and his/her caregiver(s). Though it is often one of the more emotionally salient and charged encounters for the caregivers, it is simply another experience in the life of a developing infant, not necessarily holding any particular emotional weight beyond other daily sources of distress (e.g. hunger, elimination, dressing, transitions, surprises, etc.). Thus, Sroufe and colleagues remind us that insecure attachment is related to “less sensitive care... across contexts [emphasis added]...” In particular, anxious-avoidant attachment is associated with caregiving characterized by “emotional unavailability and chronic rejection,” and anxious-resistant attachment with “interfering, ignoring, and unreliably responsive care.”
While evidence does support the importance of the parent-child relationship for the development of sleep-wake state organization, we must remember that it is the whole relationship that matters, not just the circumstances around sleep. In fact, one can argue that it is only within a pre-existing secure attachment that successful sleep training can occur at all. After all, as Thomas Anders wrote in 1994, “[t]he infant’s falling asleep each night is a separation, and waking up is a reunion…[so] sleep serves as a relevant stimulus to trigger the attachment system.” Videosomnography data at the time suggested that the type of parent-child bedtime interactions predicted the infant’s ability to self-soothe. Several subsequent longitudinal studies, including an article in this Journal by Beijers et al. (link below) also support the hypothesis that it is attachment that allows the organization of sleep, and not the other way around.
We can also look to the literature on resilience to help us understand this relationship. In their 2008 review, Ozbay et al. tell us that while “early [childhood] exposure[s] to severe stress [e.g. maternal depression, neglect, physical danger, etc.] can cause sensitization of neurobiologic systems and behaviors, early mild to moderate stressors can actually have the opposite effect and result in stress inoculation...” allowing an individual to adapt to and become more resistant to stress. The Center on the Developing Child at Harvard University calls the former type “toxic stress” and the latter types “positive” and “tolerable stress.” They point out that “[l]earning to cope with manageable threats to our physical and social well-being [i.e. positive or tolerable stress] is critical for the development of resilience.” Having to figure out how to deal with life’s little obstacles and hardships allows children, with the coaching and support of trusted adults, to develop and strengthen their abilities of self-regulation and executive function; which in turn, along with social supports, are protective of the child’s well-being during times of significant adversity.
In sleep training our children, we are simply providing the opportunity and encouragement for them to learn to self-soothe; a little positive stress in one of the first tests of self-regulation in life. By proceeding in a systematic and predictable way, while periodically affirming our presence, we reassure our child of their safety and of our love; even as we allow them to solve the challenge of sleep regulation by themselves. Thus, do they gain competence and independence in this most crucial of skills.
--Jeffrey H. Yang, M.D.