A study led by the Universities of Rochester and Washington shows that on average, men pick up on visual motion significantly faster than women do.
Men and women show surprising differences in seeing motion. Image credit: Free-Photos.
“We were very surprised. There is very little evidence for sex differences in low-level visual processing, especially differences as large as those we found in our study,” said study co-lead author Professor Scott Murray, from the Department of Psychology at the University of Washington.
The study, which involved 263 participants, shows that both males and females are good at reporting whether black and white bars on a screen are moving to the left or to the right — requiring only a tenth of a second and often much less to make the right call.
But, compared to men, women regularly took about 25 to 75% longer.
“The faster perception of motion by males may not necessarily reflect ‘better’ visual processing,” the scientists said.
“Faster motion processing has been observed in individuals diagnosed with autism spectrum disorder (ASD), depression, and in older individuals. All three of these conditions have been linked to disruptions in the brain’s ability to ‘put the brakes’ on neural activity.”
“This regulatory process may also be weaker in the male brain, allowing males to process visual motion faster than females.”
The researchers were using the visual motion task to study processing differences in individuals with ASD.
Because boys are about four times more likely to be diagnosed with ASD than girls, they included sex as a factor in their analysis of the control group, the members of which did not have ASD. The sex difference in visual perception of motion became immediately apparent.
To confirm the findings, the team asked other investigators who had used the same task in their own experiments for additional data representing larger numbers of study participants. And those independent data showed the same sex difference pattern.
“We aren’t quite sure where these differences are coming from,” the study authors said.
“So far, the difference between males and females appears to be specific to motion — there were no differences in performance in tasks that involved other types of visual information. The differences aren’t apparent in functional MRI scans of the brain, either.”
Overall, according to the study, the results show how sex differences can manifest unexpectedly.
The results also highlight the importance of considering sex as a potential factor in any study of perception or cognition.
“These findings come as evidence that visual processing differs in males and females in ways that hadn’t been recognized,” the scientists said.
“The results also provide a new window into differences in neural mechanisms that process visual information,” said study co-lead author Dr. Duje Tadin, from the Departments of Brain and Cognitive Sciences, Ophthalmology, and Neuroscience at the University of Rochester.
The research appears in the journal Current Biology.
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Scott O. Murray et al. Sex Differences in Visual Motion Processing. Current Biology, published online August 16, 2018; doi: 10.1016/j.cub.2018.06.014
