Recent research looking into the inability to detect clearly visible, perceptual changes (Simons, 2000) has demonstrated that our subjective belief in a richly detailed perceptual world might be an illusion. It has been suggested that this phenomenon referred to as change blindness demonstrates the necessity of attention for conscious perception. Based on the growing evidence demonstrating that visual stimuli that have not been perceived may still be encoded (e.g. Mack and Rock, 1998), we explored whether the changed information in a change blindness array is encoded despite its unavailability to consciousness. 10 observers viewed 3X3 randomly generated consonant letter matrices. On each trial, 2 matrices were presented, separated by an 80msec gray field. One of the rows in the second matrix always changed. A cueing tone signaled which row of the second matrix the subject was to report. Subjects were also asked to report whether a change had occurred and to which row. Following their responses subjects were asked to identify a severely degraded letter trigram that was novel, an unchanged row or the changed row. Results showed that when change blindness occurred, subjects were equally as good at decoding the changed row trigrams as those from unchanged rows, both of which were correctly decoded significantly more often than the novel trigrams (p<=.01). We conclude that information about the change is encoded despite its unavailability to consciousness.

Simons, D. J. (2000). Change Blindness and Visual Memory: A Special Issue of the Journal Visual Cognition. Philadelphia, PA: Psychology Press.

Mack, A. & Rock, I. (1998) Inattentional Blindness. Cambridge : MIT Press.