Graham Pike, Professor of Forensic Cognition, writes: Last month (June 2012) Alex Stone published his book “Fooling Houdini: Magicians, Mentalists, Math Geeks, and the Hidden Powers of the Mind“. I’ve not read it yet, but the description of stories from the underground magic scene in New York, the Magic Olympics and centuries old magical societies certainly sounds enticing (if you like that sort of thing!). However, the reason the book came to my attention is Stone’s attempt to use magic to give insights into psychology, particularly how the mind perceives the world. You can see Stone talking about the book on the BBC website here.
Using illusion and trickery to explore perceptual abilities is nothing new. In the early twentieth century, perceptual illusions were used by the Gestalt school of psychology to produce a series of laws that explained how we make sense of our visual environment. In addition, figures such as the Muller-Lyer illusion were used to support Constructivist theories of perception that demonstrated the role of prior knowledge in interpreting even the most basic of visual figures. To find out more about the history of psychology, click here.
Visual illusions are a powerful method of showing that we do not see the world exactly how it is and also an invaluable teaching and learning tool because they neatly demonstrate psychological phenomena (literally) right in front of your eyes. The power of such psychological ‘trickery’ was really brought home to me last year, when my research group organised a conference (led by Dr Hayley Ness) about ‘Constructions of Evidence’, at which our keynote speaker was Lord Justice Leveson. One of our speakers, Dr Itiel Dror, used a psychological trick to prove to the audience that although we see expertise as a positive attribute, it can actually lead to errors in judgement. The trick he used was this – count the number of ‘f’s in the following sentence:
“finished files are the result of years of scientific study combined with the experience of years”.
Most of the audience, including judges and lawyers, counted a total of 3 ‘f’s – how many did you count (?) – but actually the sentence contains 6 ‘f’s! The problem is that we have developed such an expertise in reading that we tend to disregard less important words such as ‘of’. Itiel’s research has shown that similar mistakes are made by forensic experts, who are as prone to cognitive bias as the rest of us. Trying to convince forensic practitioners that their mind may be playing tricks on them is a very hard task, but it was clear that the demonstration Itiel used had a real impact on them.