Parents are largely taking this advice. A survey conducted in Canada on the use of graduated extinction for sleep found that more than 70% of parents reported starting before six months (Loutzenhiser et al., 2014); however, 40% of those said that the approach “didn’t work at all.” The authors suggest that the lack of effectiveness in this group may indicate that the real-world applications differ vastly from the lab and that parents are using extinction too early.

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The concerted endorsement of extinction (crying it out) under six months represents a significant departure from what is known from existing research, as well as from knowledge about the neurological and developmental trajectories of sleep and emotional regulation. A review of the literature on behavioral infant sleep interventions reveals that the advice to start this early is not empirically well-supported (Gordon, 2022).

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Research on the use of extinction with this age group is limited.

Very little research has been conducted using extinction (graduated or other forms) with infants under six months. Indeed, one of the most seminal extinction researchers submitted that the intervention should not be used before six months and under a year should only occur under close monitoring (France, 1994). An update of a literature review on this topic (Gordon & Hill, 2007) found that of the 49 studies listed as empirical support for extinction, only five included any infants under six months (Eckerberg, 2002, 2004; Matthey & Speyer, 2008; Symon et al., 2005; Weir & Dinnick, 1988). Of the studies supporting the “well-established” criterion (Kuhn & Elliot, 2003), only one included any infants younger than six months (Symon et al., 2005).

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Studies that include younger infants typically do so only as part of a much wider sample (e.g., 4- to 48-months; Eckerberg, 2004; 4-52 months; Weir & Dinnick, 1988; 3 weeks-36 months; Matthey & Speyer, 2008) with results reported as an average for the group. They do not report how many participants were in various age brackets or parse the results by age. As a result, we do not know how younger infants fared compared to the older children in the sample.

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Some studies aimed at preventing sleep problems by working with newborns typically employed extremely limited waiting periods (e.g., five minutes or less; Crncec et al., 2010; Matthey & Speyer, 2008), not the much longer delay suggested in parent-directed advice books for this age group (e.g., 45 minutes to no maximum, Weissbluth, 2015). As a result, interventions for young infants that are reported to be empirically supported differ significantly from the real-world instructions given to parents, which guarantee that such interventions will not be harmful for newborns. We do not actually know this to be true from an empirical perspective.

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Investigation of negative side effects is limited.

Though researchers and others continue to maintain that extended crying has never been shown to be harmful, detailed investigation of this point is lacking. Most studies on extinction did not gather data on outcomes other than sleep behavior. Claims about the lack of negative side effects of extinction can be traced to only a small number of studies (all on children over six months; Eckerberg, 2004; France, 1992; France et al., 1991; Gradisar et al., 2016; Hiscock, Bayer, et al., 2007; Matthey & Crncec, 2010; Price et al., 2012).

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The assessment of negative behavioral or emotional effects (Eckerberg, 2004; France, 1992; France, Blampied, & Wilkinson, 1991) has primarily relied on parent report or responses to the Flint Infant Security Scale (FISS; Flint, 1974). The FISS was originally constructed in the 70s as an assessment of security —an early conceptualization of attachment —in institutionalized infants. Given the proximity of the two terms, the scale's results have been frequently misinterpreted as evidence of a lack of impact on attachment (Didden et al., 2011). This is not the case.

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The FISS endeavored to assess security, which the author defined as self-trust and dependent trust. Statements such as “Accepts new foods readily,” “Enjoys rough play,” “Recovers readily when physically hurt or if feelings are hurt,” or “Enjoys crowds” are considered indicative of infant security. These items appear to measure aspects of temperament more than emotional security. To date, the FISS has not been validated or normed on non-institutionalized populations of infants as an assessment of behavioral lack of impact. It also has never been fully tested for concurrent validity as a measure of attachment.

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Other measures have also been utilized including the CBCL (Hiscock et al., 2008; 8-10 mos.; Reid, Walter, & O'Leary, 1999; 16-48 mos.), the Strange Situation (Gradisar et al., 2016; 6-16 mos.) finding no long-term effects. It is nevertheless inaccurate to say that all crying in an extinction context is benign. This question has not been asked. While it is true that some crying in many contexts is without harm, the same may not hold true when crying gets extreme or within certain family contexts or for certain temperamentally reactive children.

For younger infants, these effects may be even more important to consider. Given the rapid brain development that occurs in early infancy, unmodulated distress (i.e., when parents let a baby cry for longer than a few minutes) may exceed their immature capacity to down-regulate. The regions of the brain experiencing the most rapid growth are the most vulnerable to disturbance (Webb et al., 2000). During these reorganization periods, very little stress can throw an organism off balance (Schore, 1996). The ability to tolerate distress is highly maturation-dependent (Kopp, 1989; Schore, 1996) and, as a result, similar quantities of crying would be experienced differently based on available self-calming resources at various ages.

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Furthermore, for temperamentally or neurologically sensitive infants, the distress may be more intense, and they may have fewer resources to manage it. It is possible that extended distress and elevated cortisol in some infants, at certain points of development, or in specific family contexts may be concerning. To date, research on this point has not been conducted.

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There has been little investigation of infants for whom extinction does not work.

Existing systematic reviews (Mindell, Kuhn et al., 2006) and clinical practice recommendations suggest that extinction is effective for 80% of infants. This leaves at least one in five infants for whom this approach does not work. Across extinction studies, the success rate is lower with 20-50% reporting lack of success. Surveys of parents have indicated a similarly high rate of intervention failure. A parent survey conducted in Canada on the use of graduated extinction for sleep found about 40% of parents said that the approach “didn’t work at all” (Loutzenhiser et al., 2014). A large U.S. parent survey of infants under 18 months found that about a third of parents reported that forms of extinction “didn’t work at all.” When participants included toddlers, the percentage rose to about 40% (Gordon, 2020).

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No research has been conducted on the need for or innate benefit of intervening before six months.

Popular advice suggests that waiting until after six months ensures that the process will be more difficult (Dubief, 2017; Mindell, 2009; Weissbluth, 2015). Research has suggested that early sleep problems inevitably do not resolve on their own (Byars et al., 2012; Zuckerman et al., 1987). While it is true that sleep problems that go unaddressed will persist, no research has examined whether there are any innate benefits of starting early or problems with waiting until the six-month mark (Thomas et al., 2014). In fact, the four-month developmental regression may make intervening at this point even more difficult. The notion that sleep interventions will be more difficult if parents wait until six months or later has never been investigated.

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Results of prevention studies can be nonexistent, small, or ephemeral.

In studies aimed at preventing sleep problems by intervening early, differences were seen at the end of intervention, but not at follow-up (Hauck et al., 2012; Wolfson et al., 1992). In many cases, both intervention and control groups improved (St. James-Roberts et al., 2001). One study comparing a behavioral intervention to an educational intervention and a control group found statistical differences in the number of “uninterrupted nights,” but actual differences were small (0.5 more uninterrupted nights; Sleep et al., 2002). Other studies found changes in parental perceptions (e.g., confidence, mood), but not necessarily in the infant’s sleep behavior (Adachi et al., 2009). Others found no differences between intervention and control groups (Galland et al., 2017; Hiscock, Cook, et al., 2014).

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Behavioral approaches in research are typically part of a larger package of interventions that include significant parent support.

A review of the more recent research on younger infants was not focused on the use of extinction per se, but instead on educational interventions designed to prevent problems from taking root. Such interventions were often conducted in the context of individualized consultations and regular follow-ups with providers (Adachi et al., 2009; Didden et al., 1999; Eckerberg, 2002; Fisher et al., 2004; Matthey & Speyer, 2008; Smart & Hiscock, 2007; Stremler et al., 2013). A few studies were conducted at in-patient parenting centers, where mothers received instrumental (help with the baby) and social support (therapy, education), in addition to information on sleep (Fisher et al., 2004; Matthey & Speyer, 2008; Stremler et al., 2014). 

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Given what is known about the impact of social support on sleep behavior (Weir & Dinnick, 1988) and the role of parental self-efficacy in outcomes (Cutrona & Troutman, 1986), it is unclear what part of the intervention was instrumental. Some have suggested, in fact, that ongoing support may be key to success: “Merely advising parents to ignore their child and leaving them to their own resources is inadequate in many cases, and possibly harmful in that a parent already lacking in confidence may face yet another failure" (Seymour et al., 1983, p. 222).

 

Another study found that:

the majority of parents who participated in the study had previously received advice from their pediatricians to implement one of these treatments, but had been unable to do so on their own; thus, knowledge of how to treat children's sleep problems was not sufficient. (Reid et al., 1999, p. 14)

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In one study on graduated extinction in a group setting, parents reported that just having an established routine helped sleep improve and the group setting helped normalize their experience and reduced feelings of isolation (Hall et al., 2006). In another study, just keeping a sleep chart improved sleep in nearly 40% of the sample (Largo & Hunziker, 1984). The assessment, support, and follow-up parents receive in these studies are rarely accounted for in results. Further, real-world implementation of sleep advice is often done in isolation with just a book or the internet for guidance.

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Details on sleep interventions in behavioral packages are often lacking.

In many studies with younger infants, detail about responding to nightwakings is not provided. For example, one study indicated that parents were given information about “the importance of self-soothing back to sleep” (Paul et al., 2016, p. 3), but did not provide more detail about what that meant in practical terms for parents’ behavior. Other studies merely say that education included information about “normative sleep” and “appropriate responses to waking” without further detail about what responses should be (e.g., Santos et al., 2016). It is difficult to know what behaviors were actually instrumental in outcomes.

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Parents strongly dislike it (or won’t use it)

Researchers have reported being surprised at parents’ dislike of extinction. In one study, five out of seven parents dropped out due to possible assignment to the extinction group. “A number of people called but declined to participate or even let the experimenter visit their homes because their child might be assigned to the ignoring condition" (Rickert & Johnson, 1988, p. 209).

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Personal endorsement of an intervention directly affects the outcome. The Canadian parent survey found that those parents who did not feel good about using extinction had significantly less improvement and felt the process was more stressful (Loutzenhiser et al., 2014).

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Research often submits that parents who have concerns about letting their children cry are merely misinformed (Byars & Simon, 2016) and their concerns are unwarranted because of the documented lack of negative side-effects (Crichton & Symon, 2016; Didden et al., 2011; Honaker & Meltzer, 2014). Instead, researchers and others suggest providing “cognitive restructuring” so that parents stop worrying about their infants crying.

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It begs the question: Why do we have to try so hard
to talk parents into this, and is it the only way?

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Time to change the thinking about sleep and sleep training

Crying-it-out is so largely considered uniformly effective that research has failed to ask any other questions:

·      Are there differential effects for younger versus older infants?

·      Who doesn't it work for?

·      How much crying is too much? at what ages?

·      Do alternatives exist that are more palatable for parents and just as effective?

 

Alternatives do, in fact, exist. Behavioral approaches that allow parental presence and decremental soothing (Blunden, 2011; Blunden & Dawson, 2020; Middlemiss et al., 2017) have been shown to be effective and circumvent many of the most difficult aspects of extinction. It is interesting to note that the intervention called camping out includes two quite different definitions: parental presence during pure extinction, as well as a fading process where the parent gives hands-on support and fades that intervention over a period of a few weeks (Hiscock, 2008). Given that parental withholding of response is considered the most difficult aspect of extinction, why is the fading version of camping out not investigated in its own right? Because of the significant body of research on extinction, it remains the most recommended approach. It is possible that extinction is not the most effective, but rather, simply the most researched.

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Research and advice continue to exhort parents to adopt a paradigm that is contrary to how they generally think about and respond to their infants. It is time to ask different questions about sleep training and to investigate other approaches that do not require parents to "steel themselves" in order to withstand their normal impulse to assist their infant with distress.

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References