Researchers from the University of Washington explored how sleep strategies used with young children across fourteen diverse cultures relate to early temperament, publishing the results in a psychology journal focused on boundaries and behavioral development. A cross national team gathered insights from 841 caregivers spanning Belgium, Brazil, Chile, China, Finland, Italy, Mexico, the Netherlands, Romania, Russia, Spain, South Korea, Turkey, and the United States. Caregivers reported on their children’s temperament when the children were between roughly 14 and 40 months old and described the sleep routines they used to help them settle for the night.
The study revealed that the approaches families choose to help their children sleep appear to shape temperament in meaningful ways. Differences in cultural practices around sleep were linked to varying temperamental profiles, and the magnitude of these differences increased when considering cross cultural comparisons. In other words, the cultural context matters a great deal when examining how sleep routines relate to a child’s mood and behavior patterns across days and weeks.
Across the sample, children in places that favored more passive strategies for winding down tended to display higher levels of social engagement and self regulation. Passive methods included gentle caregiver activities such as hugging, soothing songs or lullabies, and shared reading at bedtime. In contrast, families that leaned toward more active routines tended to report greater susceptibility to negative emotions in children, including fear, episodes of anger, and periods of sadness. The association suggests that how a family invites a child toward sleep can influence emotional patterns that emerge during the preschool years.
Geographic patterns emerged as well. Passive bedtime routines were reported more frequently in the United States, Finland, and the Netherlands, while more active wind-down practices appeared common in Romania, Spain, and Chile. These trends align with broader cultural norms around expressiveness, caregiving styles, and expectations for child self regulation. The researchers stress that no single method guarantees a particular temperament, but the data indicate consistent links between sleep socialization and early emotional development across varied cultural settings. The results contribute to a growing understanding that bedtime time is not merely a routine; it can be a meaningful context for shaping a child’s behavioral tendencies and emotional life over time. The findings were published in a peer review journal focused on developmental boundaries of psychology and involved careful interviews and standardized questions about child temperament and nightly practices, with attribution to the University of Washington team conducting the study.