The days when our parents rocked us in their arms are far behind us… This soothing swinging motion helped us fall asleep. But Swiss scientists wondered if this rocking motion could be beneficial even after these tender years. For their study, they invited adults to be rocked in their laboratory. What effects did it have on their sleep and memory?

As early as 2011, Laurence Bayer and her colleagues demonstrated the possible benefits of a slight rocking motion on falling asleep for a nap. This new research, led by L. Bayer and S. Schwartz, involved consolidating these results by studying whether the positive effects could be generalized to longer periods of sleep.

Eighteen young adults (average age = 23 years) were recruited to spend three nights in a laboratory. The team of scientists from the department of neuroscience (University of Geneva, Switzerland) observed the participants’ sleep habits and analyzed their brain waves. The first night wasn’t recorded; the subjects simply familiarized themselves with their surroundings. For the following two nights, they were randomly assigned either to a “normal” bed, or to a rocking bed (a gentle lateral rocking motion was created with the help of a motor).

The results show that the rocked participants did not sleep longer than the non-rockers. They did however fall asleep more quickly, enjoyed a longer deep sleep phase, and experienced fewer micro-awakenings.

Since sleep quality is considered to be crucial for memory processes, the research team wanted to see whether the rocking had an influence on declarative (explicit) memory consolidation. To test memory, the scientists asked the participants to learn pairs of words the night before and then recite them the next morning. They found that people in the rocking group performed better on these tests. The electroencephalogram (EEG) showed that the continuous rocking motion helped synchronize neuronal activity in the thalamocortical networks, which play an important role in sleep and memory consolidation.

This research supports avenues for developing drug-free approaches for treating sleep, mood, and memory disorders. The authors note that future work will need to explore deeper and more specific brain structures that are involved in the effects of rocking on sleep.

Perhaps soon hammocks and rocking chairs will be prescribed so we can sleep like babies again…