The larger range of space that a person considers to be “near,” the more likely it is he or she will feel claustrophobic, according to a study published in June in Cognition (Vol. 119, No. 3).

At root is a phenomenon by which phobias either cause people to perceive the world differently than those without such fears or abnormal perceptions themselves cause phobias. “We’ve known for a long time that fear and anxiety can disrupt cognitive processes,” says Stella F. Lourenco, PhD, a cognitive psychologist at Emory University in Atlanta, who led the study.

For example, a person who fears losing control over her car might perceive inclined bridges as steeper than they really are. Researchers thought something similar might be going on with claustrophobia but hadn’t been able to quantify it. Lourenco and her colleagues investigated that phenomenon by exploring a quirk of the visual perception system: When people estimate the midway point of a straight line, they tend to err slightly to the left when they’re close to the line and slightly to the right if they’re farther away.

The researchers set up an experiment in which 35 participants individually stood close to a horizontal line on a wall and used a laser pointer to indicate the midway point. Then they moved back a few feet, pointed again, and so on for nine different intervals. Just as previous research has shown, as participants drifted away from the line, their midway estimates shifted from the left to the right. By looking at how quickly their estimates changed, the researchers were able to determine the size of each participant’s “near space” — the range at which the person’s laser pointer remained left of center.

Then, Lourenco asked the participants how likely they were to experience claustrophobic symptoms in a variety of situations, such as being stuck on a train or in a dark closet. She found that participants with the largest near spaces were also the most likely to report claustrophobic symptoms, probably because encroaching on a person’s personal space triggers fear and anxiety.

“It may be a defensive mechanism that kicks in because people feel the need to protect their bodies from harm,” Lourenco says.

—M. Price