Glad you made it! But how many tries did it take you to get here? One? Five? Sixteen? If you found it on the first try, you are either very good or very lucky; most people don't usually choose the correct one until they've guessed three or four fakes. Why? We see pennies nearly every day, yet we don't remember their details. Human minds are efficient, and all they need to distinguish a penny from the other change in your pocket is the color and maybe the size.  There is no need for them to remember every detail, down to where the dates are and what the header is (unless you're doing this experiment or playing a trivia game).   Okay, now on to more experiments!
 
Go to the Applied Cognition page more "puzzles" like this!