1- Self-soothing : Is the ability of babies and children to find comfort on their own, without the intervention of another person, at any time of the day or night, whether at bedtime or during nocturnal awakenings between the sleep trains.

2- Sleep autonomy : It occurs when children manage not only to fall asleep, but also to go back to sleep on their own when they wake up at night, without calling their parents (without signaling their awakenings). In this case, the child is said to have acquired the ability to link sleep trains.

These two skills are closely linked, and are acquired in interlocked stages. Initially, the child discovers self-soothing through personal development and a supportive environment. This learning process eventually leads to complete autonomy in sleep. We can imagine this as the evolution of a baby who belly crawls, crawls on all fours and then simply walks.

One step at a time: to each his own rhythm with its back and forths

From the age of 4 to 6 months, certain self-soothing behaviors can be observed in babies, such as thumb-sucking for some. Self-soothing behaviors tend to increase up to the first year of life, such as physical contact with themselves (crossing their feet or hands), physically grasping objects or parts of their body, or staring. These are all small steps towards sleep autonomy, just like the distance covered on all fours before walking alone.

Around the age of 1, it has been documented that over 50% of children report being awake at night, requiring a parental presence to comfort them. This enables them to take small steps towards sleep autonomy, one awakening at a time and at their own pace.

Self-soothing associated with sleep is not a stable behavior over time; as with walking, children oscillate for a time between “four-leggedness” and walking. Research shows that children go back and forth between reported arousals and sleep autonomy, as they alternate between self-soothing and the need for comfort within the same night and between nights over time, depending on what’s going on in their lives (moving house, starting school, colds, etc.). These shifts are not regressions per se, but rather an adaptation to the transition to sleep autonomy.

Overall, self-soothing is a skill that develops gradually in young children, paving the way for sleep autonomy. The transitional object, such as the cuddly toy, is often seen as a favorable tool for this gradual learning process.