What's this 'scotomisation' in The Da Vinci Code?

Also in this week's column:

• What lies within: Life in the human body
• What happened to haemophiliacs before blood supplies were safe?
• Is the brain-sex theory founded in fact?

What's this "scotomisation" in the The Da Vinci Code?

Asked by Rita Hamblyn of New York City

In the current blockbuster film, The Da Vinci Code, there is an important scene where Robert Langdon (Tom Hanks), Sophie Neveu (Audrey Tautou), and Sir Leigh Teabing (Ian McKellan) discuss the possible hidden images in Leonardo da Vinci's masterpiece, The Last Supper.

Does the picture depict John the Apostle or Mary Magdalene? Are there signs that Mary and Jesus are married? Where in the picture is the Holy Grail? Is it there at all?

At one point in this scene, Sir Leigh refers to scotomisation - a word not in the current vocabulary of most film goers - and he hardly explains its meaning. Understanding this concept is one of the keys to unlocking the mystery within a mystery within a mystery: Why people perceive differently what's in The Last Supper, the artistic and historical mysteries surrounding it, and the mystery of why there's all the excitement about The Da Vinci Code book and movie.

"Scotomisation" is the psychological tendency in people to see what they want to see and not see what they don't want to see - in situations, in themselves, in anything, even in a painting - due to the psychological impact that seeing (or not seeing) would inflict.

In this case, it is one of the most famous paintings of all time and an icon in the faith of millions of Christians. The emotional power of this is considerable. It is no wonder then that The Da Vinci Code book and film have been so controversial throughout the world.

Perception involves seeing and processing information through the filter of our intellect and our emotions. That's why people often see the same thing differently. Scotomisation can be a false denial but also a false affirmation of our perceptions.

The term used in behavioral science is borrowed from the science of optics and ophthalmology. “Scotoma” is from the Greek word skotos (to darken) and means a spot on the visual field in which vision is absent or deficient.

The French psychiatrist Rene Laforgue (1894-1962) is thought to be the first to have used the term in a psychiatric sense. In a 1925 letter to Sigmund Freud, Laforgue wrote that "scotomisation corresponds to the wish that is infantile...not to acknowledge the external world but to put the ego itself into its place..."

At the time, Laforgue was talking about denial and repression in schizophrenics, but the term can have a more general application.

Psychiatrist R.D. Laing (1927-1989) describes scotomisation as a process of an individual psychologically denying the existence of anything they see with their own eyes that they really don’t want to see and hence don't want to believe.

He writes in Interpersonal Perception (1966) that scotomisation is "our ability to develop selective blind spots regarding certain kinds of emotional or anxiety-producing events". So it may be a matter of faith with the evidence of The Da Vinci Code.

Seeing is believing, but not always.

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to s.juan@edfac.usyd.edu.au