In a study by the Universities of York and Kyoto, researchers asked participants to look at pairs of photographs and decide which showed a normal face and which showed a person wearing a mask.

Surprisingly, participants made the wrong call in one-in-five cases.

The 20% error rate observed in the study likely underestimates the extent to which people would struggle to tell an artificial face from the real thing outside of the lab, the researchers say

The researchers collected data from participants from both the UK and Japan to establish any differences according to race. When asked to choose between photographs depicting faces of a different race to the trial participant, response times were slower and selections were 5% less accurate.