Do sudden onsets need to be perceived as new objects to capture attention? The interplay between sensory transients and display configuration.

Yantis and Jonides (1984) and Jonides and Yantis (1988) reported robust involuntary attentional capture by sudden-onsets, the origin of which has been debated. Prominent accounts have highlighted aspects that include the "new object" status of a sudden-onset (Yantis & Hillstrom, 1994) and the substantial luminance changes accompanying their appearance (Gellatly, Cole & Blurton, 1999; Franconeri, Hollingworth & Simons, 2005), including relative differences in the amount of sensory change between target and nontarget items (Pinto, Olivers & Theeuwes, 2008). In this research we dissociate the amount of sensory change accompanying sudden onsets from the extent to which they appear as newly created objects in search displays.

When do luminance changes capture attention?

In two experiments, we examined the ability of task-irrelevant changes in luminance to capture attention in an irrelevant singleton search. By using uniform increment and decrement arrays, we were able to create changes of the same absolute magnitude, but resulting in a singleton with either higher or lower contrast magnitude, relative to other elements in the search array. A condition where a singleton changed contrast polarity without a concomitant change in the overall contrast magnitude was also included.