Everyone likes optical illusions and often see (or not) them as merely a bit of fun. However the reality (or not) is that illusions are a way of illustrating the mental shortcuts that allow us to make instantaneous but not necessarily accurate decisions. Trying to illustrate this link has always been tricky – linking an optical illusion to cognitive limitations. However this fun video might get the message home. If you have never seen the old lady illusion then it might not make much sense.