Most people have no problems in distinguishing between left and right, but a minority of people does.

Left-right confusion during surgery can lead to patient death or severe injury.

The NEST is a new psychological test to assess left-right confusion in a patient-centered model.

About 5–10% of people are highly prone to left-right confusion under surgery-like conditions.

Have you ever been confused between left and right in the last month? While most people tend to be able to distinguish left from right, about 10% to 15% of people report that they confuse left and right quite often. This can, for example, happen when driving somewhere and taking a left turn instead of a right turn. While left-right confusion is mostly harmless, there are some situations in which it can be dangerous, or even deadly.

One of these situations is surgery. Imagine somebody has cancer in their left kidney, and this kidney needs to be removed to keep the cancer from spreading. During surgery, however, the surgeon confuses left and right and accidentally removes the healthy kidney on the right side. The patient is left without a functioning kidney. This left-right confusion during surgery is a common form of so-called “Never-Events”, fully preventable medical mistakes that lead to severe injury or death of a patient (Ocklenburg & Petzina, 2026). While psychology has a wide range of research methods and tests (Mundorf and co-workers, 2026), so far, there has not been a........

© Psychology Today