Why People Have Different Senses of Bodily Space

Where does your body end and the external world begin? Your brain is calibrated to always be thinking about that question. If it wasn’t, you would be constantly bumping into things, and navigating the physical world would be difficult.

But different people draw the borders around their bodies in slightly different places. Just like people have different ideas about where their “personal space” is, they have different ideas about what scientists call “peripersonal space,” the space people see as immediately attached to their bodies

A new study titled Interoceptive Influences on Peripersonal Space Boundary and published in Cognition sheds some light on why this might be the case. It suggests that people’s awareness of their internal bodily sensations and feelings influences where they draw the boundaries between their personal space and the external world.

In the study, researchers probed people’s sense of bodily space using auditory and tactile sensations. Then, to test the people’s awareness of internal bodily sensations, they had the people count their heartbeats and estimate time passing.

As it turned out, people who were more attuned to these internal sensations drew a narrower boundary around their peripersonal space. Another way of looking at this might be to say that they had a more precise sense of where their bodily space ended, and they didn’t see their bodies as extending as far into the outside world.

Further examination showed that part of this had to do with people’s levels of private self-consciousness – that is, their awareness of their internal sensations, thoughts and feelings. People who were more perceptive of their internal bodily sensations had higher private self-consciousness and a narrower sense of bodily space.

The researchers also showed that people’s levels of social anxiety had nothing to do with their peripersonal space boundaries. In other words, how people demarcate their bodily space might have less to do with social self-consciousness and more to do with consciousness of bodily sensations as well as how attuned people are to their internal worlds versus the external worlds around them.

Image: Flickr/The Moving Architects