It has been found that fear can impair our perception of fine details, besides enhancing our ability to identify blurry shapes.
Glancing at a fearful face, which activates the brain in a similar way to feeling fear, enhances sensitivity to visual contrast, but whether it boosts vision across the board wasn't clear - up till now.
Bruno Bocanegra and Reni Zeelenberg, researchers at Erasmus University in Rotterdam, the Netherlands, showed pictures of faces with either fearful or neutral expressions to their study's volunteers.
This act was followed by a "blob" covered in stripes of varying thicknesses, reports New Scientist.
From analyses, researchers found that those shown a fearful face were better at identifying whether thick stripes were vertical or slightly tilted and worse at identifying the orientation of thin stripes than those shown neutral faces.
Scientists believe that the response may have evolved because coarse-grained features, which enable you to evaluate movement and distance, better aid survival in scary situations than fine details.
"You don't care whether the object has wrinkles, you care whether its movement is threatening," Bocanegra says.
The study has been published in the journal Psychological Science.