By Tracy G. Cassels

To read this article in Spanish, click here.

There’s a new piece in the Huffington Post (and many other news sources) about some research out of UC Berkeley presented at a recent conference (SPSP, the largest social psychology conference there is) which found that poor sleep affects our feelings of gratitude to our partners.  In fact, it may make us selfish, prioritizing our own needs over those of others, according to the researchers.  I imagine many people will jump on this as yet more proof that we must ensure we as parents get enough sleep, even if that means sleep training our kids.  Personally, I don’t think that’s where we should be going though.

Let me start by saying that I have written a lot about sleep, and will probably write much more about sleep as the years go by.  But one thing that seems to come up time and again is the importance of sleep.  People jump on the importance of sleep as an excuse to do just about anything when it comes to kids.  After all, sleep deprivation can be a factor in post-partum depression, can impair our mental functioning, and now it can ruin relationships.  So why do some of us out there argue that sleep training is bad?  That you can survive some sleep deprivation at night?  Because that is the biological norm that we should be using as the baseline for looking at sleep in new parents.

Take this new research as an example.  Sleep deprivation makes us more selfish?  Evolutionarily (or biologically) speaking, this makes little sense.  Perhaps with severe sleep deprivation (but that’s not what was assessed), but if run of the mill sleep deprivation in new parents led to them being more selfish and less likely to care for the needs of others, we’d have died out.  Part of parenting is adapting to different sleep (and if you breastfeed, co-sleep, and are able to get naps in the day, you can function quite well, why we need to fight for longer maternity leaves or flexible working conditions for new parents).  This means our sleeping needs are qualitatively different than those of an adult without children or even parents with children at different stages.  The sleep needs of a parent with a 3 month old will differ than those of a parent with a 3 year old, or a parent with three children.  And if we continue to compare parents with non-parents, we’re bound to get caught up in this cycle of forcing children into situations for which they are not biologically adapted.

When we take studies that are based on non-parents and attempt to generalize them to parents we end up ignoring very important information.  First, we may ignore the feeding needs of young infantsBabies need to feed frequently 24-hours a day (as do formula-fed infants, though generally to a lesser degree).  Their tummies are small[1] and human breastmilk is low in protein and fat, making it easily digestible, but also quickly digestible[2].  If we prioritize our sleep over their feeding needs, we are not being responsive parents.  Second, we may put our infant at a greater risk for SIDS.  One of the most common practices in our culture is to put infants asleep in their own room.  It’s typically done to try and get an infant to associate sleep as a solitary activity (which it’s not), but it also serves to increase the risk of SIDS relative to room-sharing[3]Third, we may ignore the positive effects of mother-infant synchronicity.  The mother-infant (or parent-infant, for primary caregivers who are not mothers) dyad requires that the two parties be in tune with each other.  This is typically tested using cortisol levels and most mother-infant dyads show a large correlation in their cortisol levels which enables mothers to respond quickly and appropriately to their infant’s distress.  Mother-infant synchrony is linked to emotional development and self-regulation[4] as well as being the foundation for secure attachment[5].  This type of synchrony develops naturally, and extended periods of separation between mother and infant can not only affect synchrony, but have negative effects on maternal mental well-being[6].  But perhaps most importantly for this discussion, sleep training can negatively affect this synchrony[7], with mothers who take part in extinction (a.k.a. cry-it-out) training methods losing synchrony with their infant, particularly at bedtime.

What do we take from this research then?  One of the principals of research is to understand how generalizable your research is.  This is something we have sorely forgotten when it comes to talking about research on sleep and parenting.  Studies looking at the effects of sleep deprivation are generally based on university students or community samples without consideration of parenting status.  In order to truly understand the effects of sleep quality for parents, we need to do research on sleep quality with parents.  This needs to be the baseline for which our comparisons are made.  We need to determine what is the “normal” amount of sleep a new parent can expect and then look at the effects of functioning, bonding, and responsiveness based on increases or decreases from this amount.  Because while the quality and quantity of our sleep will be affected by the presence of a newborn, it is not necessarily a bad thing.  Although some parents will know when they’ve suffered as a result of sleep deprivation (and should seek help immediately), generally, we just don’t know enough about what is “normal” for parent sleep to make any kinds of generalizations or recommendations for child or infant sleep.  So before you jump to conclusions on any new piece of research, think about whether it makes sense given your role as parent, and you may find that this research just isn’t about you.

[Image credit: Bebo Mia]

[2] Ball HL.  Breastfeeding, bed-sharing, and infant sleep.  Birth 2003;30:181-188.

[3] Watanabe N, Yotsukura M, Kadoi N, Yashiro K, Sakanoue M, & Nishida H. Epidemiology of sudden infant death syndrome in Japan. Acta Paediatrica Japonica 1994; 36: 329-332.



[6] Gerhardt S. Why love matters: how affection shapes a baby’s brain. Hove, East Sussex: Brunner-Routledge; 2004.

[7] 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 2011; 88: 227-232.