Much ado about nothing: gradient discontinuities and attention

The research described in this thesis was conducted to determine whether a gradient discontinuity (a gap) in an array of stimuli would also capture attention. A novel task was created to study this; an array of stimuli was presented for a brief period and then removed, a tilted-line target appeared at the gap location or elsewhere. Participants then made a speeded response about the target’s orientation which was found to be faster at gap locations than non-gap locations. The results of this research suggest that a gap discontinuity in a regular array of stimuli can capture attention, and can also serve as a location cue. Moreover, its capacity to do so may differ from that of other types of discontinuitie. These findings indicate that studying the operations involved in the visual analysis of gaps may help us to understand, more generally, how stimuli capture our attention.