People who project their personal space too far beyond their bodies, or the norm of arm's reach, are more likely to experience claustrophobic fear, according to psychologists.
"We've found that people who are higher in claustrophobic fear have an exaggerated sense of the near space surrounding them," said Emory psychologist Stella Lourenco, who led the research.
"At this point, we don't know whether it's the distortion in spatial perception that leads to the fear, or vice versa. Both possibilities are likely," she said.
Everyone experiences claustrophobic fear to some extent, but there is a wide range of individual differences. About 4 percent of people are estimated to suffer from full-blown claustrophobia, which can cause them to have panic attacks when travelling through a tunnel or riding in an elevator.
Some people seek medical treatment for the condition.
Claustrophobia is often associated with a traumatic experience, such as getting stuck in an elevator for a long period.
"However, we know that some people who experience traumatic events in restricted spaces don't develop full-blown claustrophobia," said Lourenco.
"That led us to ask whether other factors might be involved. Our results show a clear relation between claustrophobic fear and basic aspects of spatial perception," he said.
Neural and behavioral evidence show that we treat space that is within arm's reach differently from space that is farther away.
"It makes adaptive sense to be more aware of things that are closer to the body, for both utilitarian purposes and defensive ones," said Lourenco.
"It also makes adaptive sense to be afraid of things that are too far away from you on the vertical dimension, since there can be a great cost to falling," he added.
The study will appear in the journal Cognition.
