3 ms·

Best theory I've heard of this is that it's due to chromatic aberration in the lens of your eye. Blue is deflected slightly to the left/right relative to red/y

• yarg 8y ago
  Maybe, but I think that we'd've evolved a way around it - probably doable in terms of the distribution of the different cones in the eyes. One thing that stands out to me is the relative rarity of blue in nature. Compared to red, a blue colour is far more likely to be sourced from the sky, rather than a source up close. It's not unreasonable to think that there might be a bias toward perceiving more probable structures, similar to (but far less extreme than) what occurs with the hollow face illusion.
• ebg13 8y ago
  That doesn't explain the white/black background difference shown at the end.
  • deleted 8y ago
    [deleted]
  • tbabb 8y ago
    Seems in agreement to me-- The white will contain red, green, and blue, which will make a red-green fringe against blue, and green-blue fringe against red. The sensitivity of the eye is also nonlinear, so bright-against-bright is going to have far less contrast than bright-against-dark.
• jcims 8y ago
  The effect for me is most pronounced with the blue/red heart on black background. I actually can feel my eyes focusing at different planes when I move my eyes back and forth between the two colors. I'm also of an age where items within a foot of my face are nearly impossible to focus on, and I find that I can focus clearly on the blue blocks at distances where I can't bring the red fully into focus.