Abstract
Inattentional blindness refers to the failure to see an unexpected stimulus under conditions of inattention. What if an expected stimulus was absent under the same conditions? This study explores the role of attention and expectation in perception using the Mack and Rock (1998) inattention procedure. Observers were asked to report the longer arm of a cross briefly presented in the periphery while simultaneously a color filled circle, alternating between blue and yellow, was present at fixation on every trial except for the critical trials in the inattention, divided and full attention conditions. On the critical trials, after reporting the longer cross arm, observers were immediately asked whether they had noticed anything different. If they responded "yes", they were asked to describe what. If they responded "no", they were also asked to describe what they saw on the last trial. In the inattention condition, only 3 of 15 participants reported being aware that the colored circle was absent. The remaining 12 participants reported seeing either a blue or yellow circle, which, of course, was not there. In the divided attention condition, 7 of the 15 subjects were unaware of the circle's absence and they too thought they saw a colored circle while in the full attention control condition all but one participant were aware of the circle's absence. Clearly there is a significant difference between the awareness of an absent stimulus in the inattention and full attention conditions (p = .000, Fisher's exact test). Our results are difficult to attribute to fast forgetting and argue: for the necessity of attention for awareness; against an attention-free phenomenal consciousness, and suggest that attention is not only required to see an unexpected stimulus but also to perceive the absence of an expected one. The results also underline the role of expectation in perceiving.
Meeting abstract presented at VSS 2016