Unlike determining up-down orientation, left-right orientation is a more complex process because it involves special neurological mechanisms. Numerous studies have revealed that a significant number of individuals in the population confuse their right and left in everyday life. In particular, these studies revealed that this confusion was more common in women than in men.
A surprising number of people find it difficult to differentiate left from right in their daily lives. The first major study on the subject was published in 1973 and investigated a sample of doctors and their spouses. The result ? About 9% of men and 17% of women said they frequently faced left-right confusion in their daily life.
And when 290 Irish undergraduate medical students were tested for laterality using a series of rod-shaped images, more than half of them had problems, scoring less than 77% correct answers (the test had 144 questions). Both of these studies showed that women had more difficulty than men.
It has therefore been suggested that women have more difficulty with left-right discrimination because they are less “lateralized” than men, and a lower degree of lateralization could lead to more left-right confusion (CGD).
Lateralization: it does not explain the right-left confusion
However, those studies reporting more left-right confusion for women have been criticized, because the tasks that were used involved mental rotation, a spatial ability in which men generally excel.
In a more recent study, 34 right-handed women and 31 right-handed men performed two left-right behavioral discrimination tasks, in which mental rotation was either controlled experimentally or was not required.
To measure the degree of hemispherical asymmetry, participants also performed a dichotic listening test. Although females were no less lateralized than males, the two tasks consistently found females to be more susceptible to left-right confusion than males.
Neurocognitive differences between the sexes
In another study, 16 women and 15 men observed photos of pointing hands in various orientations (turned or not turned) and were asked to identify them as left or right hands. The results revealed that CGD was particularly associated with activation in the lower parietal regions, extending into the right angular gyrus.
Regardless of the phase of the menstrual cycle (which was a particular point of study in the analysis), women, compared to men, recruited more prefrontal areas, suggesting higher top-down control of CGD. The authors concluded that there are gender differences in the neurocognitive mechanisms underlying CGD.
Although the angular gyrus is involved in CGD, several other parietal areas are at least as involved and essential. Furthermore, the hypothesis that greater left-right confusion is due to more pronounced bilateral activation in women has been rejected.
Left-Right Confusion: A Negative Self-Assessment of Women
Also, women tend to describe themselves as more confused than men when it comes to determining right and left. Studies have looked at this self-judgment in order to understand the cause. In one study, subjects were tested on a task that required quick and accurate left / right judgments, a mental rotation task, and a task that required navigating a virtual maze.
Correlations between performance and self-ratings were calculated. Men and women who gave themselves very poor CGD scores had significantly lower accuracy scores on the left / right determination task than men and women with average scores, but there was no gender-specific relationship between CGD assessment and left / right determination that would explain why women judge themselves in this way.
For females only, a weak correlation between CGD scores and virtual labyrinth navigation was observed, but no significant correlation was observed between CGD scores and mental rotation performance. The authors concluded that except for sociological reasons, no neurological mechanism explained this negative self-report. The exact neurological mechanisms behind the higher frequency of CGD in women therefore remain, for the moment, a mystery.