Visual Perception and Awareness: A Modular System

Celesia, G. G. (2010). Visual perception and awareness: A modular system. Journal of Psychophysiology, 24(2), 62-67. doi:10.1027/0269-8803/a000014

The inability to realize that one is seeing is phenomenal. The ability to not only see, but to be able to comprehend is taken for granted as a biological function in daily life. The following came from Celesia’s collection of case studies over a period of time. All of the participants had some form of lesion in the brain, one of which had a lesion which made communication between the occipital lobe and the rest of the brain impossible. One of the participants, a lady with visual agnosia, could draw out the basic shapes of objects, but never finish them, and she could copy shapes, but could not say what they were. Celesia also had participants among the case study who suffered from blindsight due to lack of blood to the occipital lobe. The participants could find objects asked of them, but did not recall finding them afterwards. In another group of individuals studied who had undergone strokes, participants vocalized only being able to see grays, none vocalized any color in their sight, but several could imagine colors.