Study Explains Spatial Orientation Differences Between Sexes; Inner Ear Size May Be Determinant

The study, published online in the journal Perception, examined whether differences in how men and women judge how we orient ourselves in our environment could be attributed to physiological or psychological causes. It found that giving the participants verbal instructions on how to determine their spatial orientation did not eliminate the differences between the sexes.

"Since the instructions didn't remove the difference between how men and women judge spatial orientation, we believe it is likely a result of physiological differences," says Luc Tremblay, a professor in U of T's Faculty of Physical Education and Health. For example, says Tremblay, the otoliths – structures found in the inner ear which are sensitive to inertial forces such as gravity – tend to be larger in men than in women, and may allow males to adjust themselves more accurately than females in some environments.

In the study, Tremblay asked 24 people (11 males and 13 females) to point a laser straight-ahead (perpendicular to the body orientation) while upright and when tilted 45 degrees backward. To test whether cognitive processes affected spatial orientation, participants – who were tested in the dark – were told to focus on external or internal cues to help them orient the laser. He found that although instructions to pay attention to internal cues helped women to point the laser significantly closer to their straight-ahead, there were still significant differences between the sexes, with women tending to look more towards their feet.

However, although women are more likely than males to misjudge what is horizontal when performing tasks in sensory-deprived or biased environments, they may have an advantage over men while performing tasks under other sensory conditions, such as driving a car or piloting a plane, says Tremblay.

This could mean that women are better than males in avoiding the worst-case scenario in spatial orientation, as women act more cautiously due to the way they interpret the sensory input, while men tend to take risks. An example, says Tremblay, is piloting a plane in a situation where visual cues have been lost. "Because women tend to judge their horizontal a few degrees below what it actually is, they tend to pull up to compensate, thus directing the plane away from the ground."

Tremblay says his finding has good potential for practical applications such as designing gender-specific training for extreme situations such as piloting and space flight. "It's important to identify how men and women differ with respect to complex perceptual-motor behaviour in order to design recreational, rehabilitation and work environments that ensure safety and top performance."

This study was published online on March 19, 2004. The research was supported by a grant from the Natural Sciences and Engineering Research Council of Canada, a Canada Research Chair awarded to Digby Elliott, one of the paper's co-authors, and a scholarship from Les Fonds pour la Formation des Chercheurs et l'Aide à la Recherche du Québec awarded to Tremblay.