!["Shadows"](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/shadows-section-title/2934071-2-eng-US/shadows-section-title_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/shadows-section-title/2934071-2-eng-US/shadows-section-title_full_990.png 850w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/shadows-section-title/2934071-2-eng-US/shadows-section-title_full_1468.png 850w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/shadows-section-title/2934071-2-eng-US/shadows-section-title_full_1980.png 850w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/shadows-section-title/2934071-2-eng-US/shadows-section-title_full_2475.png 850w)
Look at the horizontal bar in the middle. Is it all one solid shade of gray? Or are there darker and lighter parts?
![Gray rectangle in front of a black-to-white gradient background.](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/contrast-illusion/2936093-1-eng-US/contrast-illusion_full_495.jpg 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/contrast-illusion/2936093-1-eng-US/contrast-illusion_full_990.jpg 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/contrast-illusion/2936093-1-eng-US/contrast-illusion_full_1468.jpg 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/contrast-illusion/2936093-1-eng-US/contrast-illusion_full_1980.jpg 1600w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/contrast-illusion/2936093-1-eng-US/contrast-illusion_full_2475.jpg 1600w)
It’s just one shade of gray!
Look at the two dinosaurs. Are both the same color, or are they different?
![Two identical dinosaurs on a yellow-to-purple gradient background.](/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/dinosaur-illusion/2941569-1-eng-US/dinosaur-illusion_full_495.png 495w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/dinosaur-illusion/2941569-1-eng-US/dinosaur-illusion_full_990.png 990w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/dinosaur-illusion/2941569-1-eng-US/dinosaur-illusion_full_1468.png 1468w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/dinosaur-illusion/2941569-1-eng-US/dinosaur-illusion_full_1980.png 1920w,/var/ezflow_site/storage/images/media/amnh/images/explore/ology-images/brain/optical-illusions/dinosaur-illusion/2941569-1-eng-US/dinosaur-illusion_full_2475.png 1920w)
They’re the same!
Your brain is overruling your eyes again, trying to adjust for what appear to be differences in lighting.
The dinosaur on the lighter background looks darker than it really is. And the dinosaur on the darker background looks lighter than it really is. Take out the background shading, and you’ll see that the dinosaurs are identical!
Image Credits:
© AMNH; ©AMNH.