How are these buses sized? In 1911, psychologist Mario Ponzo proposed that surrounding cues influence item size perception. Even in flat photographs, our brains perceive depth and size objects proportionately. But these bus photographs are the same size.
Do you see movement in this image? Psychological effects of color contrasts, object forms, and position make this motionless image appear to move.
Does this image rotate as you glance around? One of numerous peripheral drift illusions. Motion is perceived by the brain's interpretation of patterns outside the eye's focus. High contrast, light and dark hues repeat to create the effect.
Which square is darker gray 1, 2? Professor Edward H. Adelson of MIT published this illusion to show how the brain's intricate processing of visual information, illumination, and experience may fool it. Both 1 and 2 are gray.
Are you seeing a spiral or rings? Sir James Fraser, a psychologist, described this optical illusion in 1908. It is a collection of concentric striped rings, hence the name “false spiral”.
Left or right red dot bigger? Psychologists Hermann Ebbinghaus discovered this relative size illusion. Your brain compares size using surrounding dots. Center red dots are the same size.
Notice anything about these square rows? The staggered rows of dark and light squares may appear sloping or curving in this geometrical optical illusion, although the lines dividing them are parallel and straight.
Do the intersecting lines have dots? What do you see when you look around? In 1994, E. and B. Lingelbach and M. Schrauf identified this optical illusion, which may be caused by “lateral inhibition” in the brain. More research is needed to determine its cause.
What's the difference in red line lengths? Arrowheads and arrowtails alone may impact line length perception. In this image, those lines are extended to form a dimensional wall design, with the red line in the far corner seeming full wall height and the closer red line not. However, red lines are same length.
Are the red lines straight or bent? Physiologist Ewald Hering discovered this geometrical-optical illusion in 1861. The two lines in front of the radial background look to bow outward yet are straight, parallel lines.