Bert is looking at a picture of a smiley face which contains two green eyes, a blue nose, and a red smile on a yellow face and is asked to stare at the blue nose. The picture is
presented on a computer screen while his eye movements are being recorded.
Furthermore, whenever his eyes move (even in the case of a microsaccade), the image
moves with his eye such that the blue nose is always presented on the same location on
his retina. After some time, what will Bert report seeing at the place of the nose?
A) it will be green, just like the two eyes
B) it will be gray because the perception of color will fade
C) it will be yellow, just like the background
D) it will look like a black gap in the middle of the face

Question

Bert is looking at a picture of a smiley face which contains two green eyes, a blue nose, and a red smile on a yellow face and is asked to stare at the blue nose. The picture is
 presented on a computer screen while his eye movements are being recorded.
 Furthermore, whenever his eyes move (even in the case of a microsaccade), the image
 moves with his eye such that the blue nose is always presented on the same location on
 his retina. After some time, what will Bert report seeing at the place of the nose?
A) it will be green, just like the two eyes
B) it will be gray because the perception of color will fade
C) it will be yellow, just like the background
D) it will look like a black gap in the middle of the face

Quizplus · Accepted Answer

When staring at a fixed point for a prolonged period of time, our brain adjusts and the colors in the periphery of our vision may appear to fade or even disappear, a phenomenon known as the Troxler effect. In this case, because the blue nose is constantly being presented at the same location on Bert's retina, the surrounding colors (the green eyes and red smile) will start to fade or disappear, leaving only the yellow background, which is the same color as the nose. Therefore, Bert will report seeing the nose as yellow after some time.

Bert Is Looking at a Picture of a Smiley Face