How Common Is It for People to Confuse Left and Right?

Have you ever been confused when distinguishing up and down? Or front and back?

This almost never happens to anyone. In contrast, a lot of people frequently confuse left and right.

Imagine driving in a car and asking a passenger whether you should turn left or right at the next intersection. The person says “right”—but after the turn is completed, they follow up with “I meant the other right!” because they had confused left and right in their mind. There are many anecdotes like this.

Driving mishaps aside, left-right confusion can have serious consequences in some situations. For example, some doctors have reportedly amputated the patient's left leg when they should have amputated the right leg, and vice versa. As such medical mistakes have serious long-term consequences for the well-being of the affected patients, it is important to understand the psychology behind left-right confusion. Unfortunately, not a lot of scientists have investigated left-right confusion so far and we do not have a good understanding of why so many people confuse left and right, but no one confuses up and down.

A recent study published in the Quarterly Journal of Experimental Psychology was aimed at getting a better understanding of left-right confusion (Van der Ham et al., 2021). In the study, the scientists performed three different experiments. Here's what they found:

1. More than 14 percent of people reported that they struggle to distinguish left from right.

In the first, the authors collected data on subjective self-reported left-right confusion and strategies to combat it in more than 400 Dutch volunteers. Overall, 14.6 percent of people rated their ability to distinguish left and right as insufficient. Regarding strategies to combat left-right confusion, the most common one was to look at the writing hand (28.2 percent of participants), followed by forming an L with the thumb and index finger (13.2 percent), remembering which side of the road cars drive on (1.4 percent), and looking at jewelry that is worn on one side (1 percent).

2. In an objective test, the percentage of left-right confusion was closer to 8 percent.

In the second experiment, the scientists objectively assessed left-right confusion. To this end, more than 200 volunteers were tested with a digital left-right discrimination task.

In the task, the volunteers looked at simple line drawings of human figures that were shown from the front or the back and that showed different arm positions that may be crossed or uncrossed. One hand was always colored red and volunteers had to indicate whether the red hand was the right or the left hand of the figure in the drawing.

Results showed that volunteers tended to be quite good at this task. For drawings in which the front side of the figure was shown, the average percentage of left-right confusion was between 7.9 percent and 10.5 percent. When the back side of the figure was shown, the percentage of left-right confusion was between 4 percent and 11.2 percent. The overall average was 8.4 percent.

In the third experiment, the scientists repeated the second experiment but varied the position of the hands of the volunteer that was tested. Moreover, they put a black cloth over the volunteers’ hands in some trials of the experiment to see whether looking at the hands would affect performance in the experiment.

The results did not differ much from those of experiment two, suggesting that hand position is not a significant factor in left-right confusion. The scientists concluded that internal body representations are relevant for left-right confusion, not actually seeing the hands.

Conclusion

Taken together, left-right confusion occurs in a limited number of healthy people, with 14.6 percent indicating that they often have trouble with left-right confusion in a subjective questionnaire. The percentage of actual left-right confusion in the objective test was a bit lower at 8.4 percent, but that may of course also be related to the test itself.

It could be, for example, that people confuse left and right more often when driving a car than when distinguishing the left and right arm in drawings. Therefore, more research on left-right confusion in everyday situations should be carried out.

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