Abstract
Numerous experiments show that people are unable to report on unattended information. Does this mean that there is no processing in the absence of attention, or merely that this information does not reach awareness? We have developed a paradigm that makes it possible to present hundreds of highly salient stimuli while the subject remains unaware of their presence. This is done by presenting the target stimuli conjoint with a rapid serial presentation of letters where subjects have to focus on. We show, by means of Magneto Encephalography, that during such a condition of sustained inattentional blindness, neural activity related to the segregation of the target stimuli from the background is nonetheless present. When subjects become aware of the stimuli additional activation of the brain is found at a longer latency and a different spatial location. Moreover, once subjects are aware of the target stimuli, there is no interference between the detection of the letters and the detection of the target stimuli. These results support the notion that, while figure-ground segregation is an automatic process, this information does not reach a reportable form of awareness until a minor amount of attention is applied to it.