If you are experiencing problems with your sleep, contact with a roommates may likely be the cause of the issue, say researchers at the University of Michigan.
Ada Eban-Rothschild, Assistant Professor at U-M’s Department of Psychology, and colleagues tracked the sleeping behavior of mice in a social context. They found that these small rodents seek body contact before falling asleep and they cuddle together during sleep. They also show that cuddling during sleep is driven by an inner motivation for longer body contact, which they termed „Somatolonging“.
The study, published in Current Biology, emphasizes the strong need for social contact in species other than humans.
The absence of this type of contact became evident during the COVID-19 pandemic, when people suffered from Somatolonging.
Ada Eban-Rothschild, Assistant Professor in the U-M Department of Psychology
Cuddling during sleep is not without cost; the mice often disturb each other while sleeping. Also, in humans, sharing sleep is not always positive, and sleeplessness can be transferred between bed partners. So why do people and other animals voluntarily choose situations that could affect their sleep? Researchers don’t yet know.
On the other hand, people sleeping together show a synchronization of multiple neurophysiological measurements, including the timing of falling asleep/waking up and REM sleep. In the study, the researchers used advanced wireless devices and video recordings to simultaneously monitor multiple mice within a group for 24 hours.
The mice were willing to give up their preferred sleeping areas to gain access to social contacts. This suggests that the motivation for longer body contact promotes clustering behavior, the researchers said.
They also noticed the coordination of multiple neurophysiological features in those who sleep together, including the timing of falling and waking up, as well as sleep intensity.
Of note, the timing of rapid eye movement (REM) sleep in male siblings sleeping together was synchronized, but not in female siblings or unfamiliar mice sleeping together. This suggests that an individual’s internal state, such as the feeling of security, controls the degree of synchronization.
The authors of the study, in addition to Eban-Rothschild, included postdoctoral researcher Maria Sotelo, lab technician Chelsea Markunas, as well as students Tyler Kudlak and Chani Kohtz, all from UM; Alexei Vyssotski, senior scientist at the University of Zurich; and Gideon Rothschild, UM Assistant Professor of Psychology.
Sotelo, MI, et al. (2023). Neurophysiological and behavioral synchronization in group-living and sleeping mice. Current Biology. doi.org/10.1016/j.cub.2023.11.065.