Hook 5: Sleep Training Vs. Co-Sleeping

What was the design in Gradisar et al.’s research?

• 43 infants, randomly assigned

• 6-16 months old (average 10.8); parents reported a sleep problem

• 3 groups of 14, 15, and 14: graduated extinction, bedtime fading, or sleep education (control)

• 12 months later: Strange Situation attachment test and a behavior checklist

What was the control group in the Randomized control trial?

The group that received educational information about infant sleep but did not receive either of the two behavioral sleep interventions.

Randomized controlled trial

families were randomly assigned to a group, and the control group received sleep education, not nothing. Random assignment is what lets researchers say more about the cause than a survey can.

What are the overall outcomes of Randomized controlled trial?

• Time to fall asleep, before vs. 3 months

  • ~13 min sooner with graduated extinction

  • ~10 min sooner with bedtime fading

  • Sleep education control group: about 2 mins later, no real change

What are the stress outcomes of Randomized controlled trial?

infants’ afternoon cortisol declined in both treatment groups; mother’s stress fell over the first month; mood did not differ

What are the night awakenings outcomes of Randomized controlled trial?

Night awakenings: large drop with graduated extinction only

What are the results of the randomized controlled trial 12 months later in terms of attachment?

no significant differences in attachment or in emotional and behavior problems

What can the Randomized control study support?

• Random assignment, with a sleep-education control group

• Both methods shortened time to fall asleep

• Cortisol did not rise, and attachment and behavior did not differ 12 months later

What can the Randomized control study not tell us?

• Small or moderate difference: groups of 14-15 fall short of the authors’ own target of 21 per group for a large effect

• Stress during the nights of treatment: it wasn’t measured

• Families unlike these: most were well educated and higher income

• Co-sleeping: bed sharing was not evaluated because of infant mortality risks

• Whether sleep training is right for every family.

What is the AAP guidance for co-sleeping with infants under 1?

Advises against bed-sharing with infants under 1; recommends room-sharing for at least 6 months, ideally up to a year; gives harm-reduction tips (firm flat surface, no soft bedding, avoid bed-sharing after alcohol or sedatives. Reduces SIDS up to 50%.

What does Motherly (2025) say about SIDS rates where co-sleeping is common?

Cites lower SIDS rates, where co-sleeping is common, and studies that found no negative effects on later behavior or cognition.

According to Gradisar, does sleep training harm attachment?

Gradisar found no evidence of attachment harm in the methods studied — 43 infants, two methods, 12-month follow-up.

What is a limitation of Gradisar's study?

The findings only apply to the methods and sample studied. Small harms cannot be ruled out.

What does the Motherly say about co-sleeping?

Motherly discusses AAP guidance and other studies, but findings may differ.

Did Gradisar study co-sleeping?

No

What is the difference between bed-sharing and room-sharing?

• Bed-sharing: Parent and infant sleep on the same surface.

• Room-sharing: Parent and infant sleep in separate sleep spaces in the same room.

What was the main purpose of the Gradisar et al. (2016) study?

To examine whether behavioral sleep interventions improve infant sleep and whether they negatively affect infant stress, parent-child attachment, or children's emotional and behavioral development

What type of study was conducted?

A randomized controlled trial (RCT). Infants were randomly assigned to one of three groups.

What is graduated extinction?

A method where parents gradually increase the amount of time they wait before responding to their infant's crying. They briefly check on and comfort the infant without picking them up.

What is bedtime fading?

A method where parents temporarily delay their infant's bedtime to help the infant fall asleep more easily. Bedtime is gradually adjusted as the infant's sleep improves.

What is the main difference between graduated extinction and bedtime fading?

• Graduated extinction focuses on gradually delaying the parent's response to crying.

• Bedtime fading focuses on adjusting bedtime to help the infant fall asleep faster.

What is sleep homeostatic pressure?

The body's natural drive to sleep. The longer someone stays awake, the stronger their need for sleep becomes.

How does bedtime fading use sleep homeostatic pressure?

By temporarily delaying bedtime, the infant builds up a stronger need for sleep, making it easier to fall asleep.

How did researchers measure sleep and stress?

• Sleep diaries completed by parents.

• Actigraphy, a monitor that tracks movement.

• Salivary cortisol to measure infant stress.

• Questionnaires to measure parents' stress and mood.

How did researchers measure parent-child attachment?

They used the Strange Situation Procedure, which observes how infants respond to separations and reunions with their caregivers.

What were the main findings about sleep?

Both methods helped infants fall asleep faster. Graduated extinction was especially effective at reducing the number of nighttime awakenings.

What happened to wakefulness during the night and total sleep time?

Sleep diaries showed improvements in nighttime wakefulness across all three groups. Total sleep time increased slightly in the graduated extinction and control groups, with little change in bedtime fading.

Did the two methods affect infant stress?

Researchers found no evidence of long-term increases in infant cortisol. Afternoon cortisol decreased in both intervention groups.

Could the study rule out all infant stress?

No. Researchers did not measure cortisol in real time during the interventions, so they could not rule out temporary stress during sleep training.

How did the interventions affect parents?

Parents in both intervention groups reported reduced stress during the first month. Parent mood also improved over time across all groups.

Did sleep training affect attachment or later behavior?

No significant differences were found in infant attachment or emotional and behavioral problems at the 12-month follow-up.

What were the main strengths of the study?

• Randomized controlled trial.

• Used multiple ways to measure sleep and stress.

• Included a control group.

• Followed up with families 12 months later.

What were the main limitations of the study?

• Small sample of only 43 infants.

• Families were relatively advantaged, limiting generalizability.

• Did not measure immediate stress during sleep training.

• Only studied two sleep training methods.

What is the difference between sleep diaries and actigraphy, and why does it matter?

Sleep diaries rely on parents reporting what they observe, while actigraphy tracks infant movement. They may show different results because an infant can wake up without signaling to their parents.

What can we conclude from this study, and what can we NOT conclude?

The study suggests that graduated extinction and bedtime fading can improve certain infant sleep outcomes without evidence of long-term harm to attachment or behavior in this sample. However, it cannot prove that all sleep training methods are harmless, rule out temporary stress, or show that sleep training is right for every family. It also did not study bed-sharing.

_______ of parents of children under 10 had co-slept at some point.

88%