By Mark Bennett

Scientific research and practical experience have shown that eyewitness testimony is often unreliable and a leading factor in wrongful convictions. Still, jurors tend to put a great deal of faith in the testimony of an eyewitness.

Eyewitness testimony can go bad because of bias, because of flawed memory, or because of flawed perception. We all think that we see things correctly and remember them accurately. The Internet recently gave us a tool to demonstrate to jurors that we are our perception of very simple things, such as the color of a dress, can be mistaken.

Some people see the dress in this picture as blue and black. Some see it as white and gold. Put the image up on the screen (test it first to make sure that the effect works on the courthouse equipment) and your jurors will disagree on what color it is. (An informal Buzzfeed poll found that 70% of people saw it as white and gold, rather than blue and black. I got about the same results at home.)

Use this to demonstrate that people of good faith, with no biases, can perceive things wrong and believe beyond any doubt that they are correct. Also use it to make the point that how sure we are about things is not a reflection about how correct we are: those who are 100% sure that the dress is white and gold are 100% wrong.