For my first blog post, I was having a hard time thinking of a personal experience which related to something we learned in class, so I decided to look online for articles regarding a topic that really stuck out as interesting to me so far in the semester. I was really struck by our lecture where we learned about brightness and contrast and how the response of edges are influenced by the light surrounding the edges, so pretty much the intensity of an object depends on the surroundings of that object, along with the Hermann Grid and Cornsweet Illusion (lecture 5.) It was really cool to me how a box of the same color surrounded by a lighter contrast appeared darker then that same colored box surrounded by a darker contrast.

The article I found was written by a man named Phil Plait, who goes into great detail of how optical illusions can have you doubting your eyes and what you are really seeing. At the beginning of the article there is an image of two “lozenges” which are pretty much three-dimensional squares that appear to be different shades set on top of each other. The one on top appears quite a bit darker then the one on the bottom, but if you put your finger up blocking where the two squares meet, they appear to be the same shade. We learned about this phenomenon when talking about the Hermann grid. With the Hermann grid, each rectangular box gets a little bit brighter and then starts getting darker and finally goes back to the original shade, yet the different shades get averaged across the entire grid to make it look like they’re shading from lighter to darker. (See Image Below)

This article directly relates to our class because it is an exact example of the Craik O’Brien-Cornsweet effect, which we also learned about during lecture 5. The Cornsweet effect is when one side of an image appears to be darker then the opposite side of that image, even though both sides of that image are the same shade of grey. Pretty much, with the Cornsweet effect and this article, our brain sees the upper square as being darker then the bottom square, with that being said, along with the different levels of contrasting shades between the two squares, our brain perceives them as different shades.

Throughout this class, I have learned time and time again that the brain has a funny way of playing tricks on us, and this is an exact example of how our brain can play tricks on us.

Plait, Phil. “An Optical Illusion You Will Swear Is Fake. It Isn’t.” Slate Magazine. N.p.,n.d. Web. 15 Mar. 2014 <http://www.slate.com/blogs/bad_astronomy/2013/12/07/optical_illusion_shades_of_grey.html>.