From an evolutionary standpoint, these theories kind of make sense: When kids are scared at night, they go to their parents' room to be comforted. In the last season of Keeping Up With The Kardashians, Kim Kardashian West told her sisters that she didn't want to sleep alone in a hotel bed in Palm Springs. She was still grappling with the trauma of her robbery a few months prior, and having someone in bed with her was comforting. For some people, the stress from a traumatic event can lead to a slew of sleep issues, so having a trusted friend or family member sleep in the room can help, according to the National Sleep Foundation . So although having another body in bed might not directly impact that person's sleep quality, it could be comforting or help to quell anxiety.