Your Bedroom Isn't That Different Than a Caveman's

As evolutionary psychologists persistently point out, vestiges of our prehistoric past often turn up in unexpected places. Newly published research suggests one of them may be your bedroom.

A German study finds our preferences regarding the placement of bedroom furniture reflect the safety concerns of our distant ancestors. According to the paper, just published in the online journal Evolutionary Psychology, our choice of room layout is remarkably consistent with the physical environment prehistoric men and women preferred.

University of Munich psychologists Matthias Spörrle and Jennifer Stich conducted an experiment featuring 138 volunteers, divided in half between men and women. (Median age was just under 30.) Each was presented with one of four floor plans for a bedroom.

Half of the rooms featured a door that opened to the right; the others had a door that opened to the left. Half had a window; the rest did not. Participants were presented with movable symbols representing items of furniture — a bed, table and chair — and asked to arrange the room to their liking.

Spörrle and Stich were curious to see whether their choices would reflect an ingrained urge to feel safe from predators. Although our earliest human ancestors slept under somewhat different conditions — for one thing, they did not spend much time worrying about the thread counts of their linens — the researchers argue we think of our bedrooms “in a similar way as our ancestors might have perceived, for instance, caves and their entrances.”

They note that, for cave dwellers, nighttime safety “can be maximized by choosing a sleeping place that (a) allows one to detect a potential aggressor as early as possible, (b) allows one to remain hidden from the aggressor as long as possible, and (c) allows for maximum reaction time in case of an attack.” Are our design choices driven by those same ingrained needs?

The study suggests they are indeed. Spörrle and Stich found 83 percent of the participants “positioned the bed in such a way that it offered a view of the door from the resting position,” allowing them to quickly recognize an intruder.

Seventy percent of the participants “positioned the bed to the wall opposite the door without leaving space between bed and wall,” they report. “Hence, a significant majority of the participants chose the maximum possible distance between bed and door.”

Finally, 74 percent positioned the door on the left side of the room if the door opened to the left, while 64 percent positioned it on the right side of the room if the door opened to the right. This placement allows those in bed to detect when the door is opened “without being immediately visible to the person entering the room.”

The evolutionary roots of these preferences are clear enough: Early men and women who adopted this safe-sleeping approach were more likely to survive and reproduce, so we are effectively their ancestors. But are there other, more mundane explanations for these likes and dislikes?

Spörrle and Stich argue such preferences are “difficult to explain purely in terms of considerations of functionality.” They grant that positioning of the bed might “be influenced by intentions to avoid a draft” emanating from the room’s entrance. But moving the bed as far from the door as possible, and choosing to sleep at the side of the room to which the door opens, are both “counter to convenience,” since they result in “a longer walk to open the door.”

Eye-opening stuff, to be sure, especially since this appears to be the first study to ever examine this issue. One question remains, however: Do these evolutionary imperatives overlap with the ancient – and trendy – precepts of Feng Shui? Comparing the two could make for a fascinating follow-up.