The Israeli researchers used “continuous flash suppression,” a powerful masking technique, to render images invisible. A series of rapidly changing, randomly colored patterns was flashed into one eye while a photograph of a person carrying out some task was slowly faded into the other eye. For a few seconds, the picture is completely invisible, and the subject can see only the colored shapes. Because the images become progressively stronger, eventually they will break through, and the subject will see them. It is like Harry Potter’s cloak of invisibility fading with time and revealing what is underneath.
The fascinating aspect of the Mudrik study is that the time to become visible depends on the content of the image. Realistic scenes that depict a woman placing a pizza into an oven, a boy taking aim with a bow and arrow, or a basketball player dunking a ball into a hoop took 2.64 seconds to become visible, whereas unnatural scenes were masked for only 2.50 seconds, a small but significant difference. That is, the unconscious mind detected something incongruent about these pictures: a woman puts a chessboard into the oven, the cocked arrow is replaced by a tennis racket, and the basketball becomes a watermelon. The psychologists made sure that both congruent and incongruent images were truly invisible and could not be distinguished from one another when masked in this way. This discovery implies that the unconscious can recognize something is amiss in these images, that the object handled by the person in the image is not appropriate to the context.
How the mind recognizes that something is wrong is puzzling. Maybe because the vast and tangled neural networks of the cerebral cortex that encode images have learned that certain objects go together but others do not (akin to the software programs—bots—that Google and other search engines employ to trawl the Internet to list all images, sentences and Web pages so when you search for them they are readily accessible). Given the sheer infinite number of possible pairings of objects and context, is this solution likely to be done by the brain? Or maybe the masking techniques suppress visibility of the image but do not fully eliminate conscious access to them? Only more research will tell. In this way, we shall ultimately know the capabilities of the cognitive unconscious and the truly essential function that consciousness plays in our life.
This article was originally published with the title Probing the Unconscious Mind.