If you can't clearly see the details, walking men appear to be coming, and walking women appear to be going.
Even when the team added some perspective cues to the models, to suggest a direction of gait, the perceived gender of the model still had a significant effect on the direction judged by the observers.
The team speculates that there might be evolutionary explanations for their results.
"If you see a male, but you don't have quite enough information to be sure if they're facing towards you or away from you," says van der Zwan, "it's probably safer to assume they're facing you, so you can get ready to fight, or for flight."
However, it might be more important for young children or infants not to misinterpret a female figure as facing them when in fact she's moving away.
"If you're young and you're not quite sure if your mother or female carer is facing you or not and she's walking, it's probably safer to assume she's leaving, because then you can get ready to follow her if you need to," he says.