Ronald A. Rensink¹ (); ¹University of British Columbia

Although inattentional blindness (IB) has been the focus of many studies, questions remain as to its nature. First, does the failure to report an item result from a lack of attention, or a lack of expectation? Second, does it correspond to a failure to consciously experience the item, or to remember it—i.e., is it a form of blindness or amnesia? And third, how is functionality affected when visual experience is not reported? Earlier attempts to answer these questions had various limitations. To overcome these, a locked-onset technique had a test item briefly appear while other items around it were tracked (Rensink, VSS 2005). Test items were in 50% of 300 trials given to each observer. If IB results from a lack of expectation, test items should almost always be seen; in contrast, the diversion of attention due to tracking should cause these to be missed. In addition, test items were endogenous cues. If cues reported as unseen differ in their effect from those reported as seen, it would imply that cues reported as unseen were not briefly experienced (and thus acted normally) before being forgotten. Four kinds of cue were used: (i) simple arrow, (ii) arrow embedded in a circle, (iii) triangle embedded in a square, or (iv) reversed arrow; these were shown for 100, 200, or 600 ms. Running 30 observers per condition indicates that (i) IB is due to a lack of attention rather than expectation, (ii) it mostly reflects a failure of perception rather than memory, and (iii) the absence of conscious visual experience during IB slows the extraction of figural elements. These results suggest that much of visual processing occurs in the absence of conscious visual experience, with such experience enabling the control of selective attentional processing, allowing perception to be sped up in nonroutine situations.