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A four-dot mask that surrounds and is presented simultaneously with a briefly presented target will reduce a person's ability to identity that target if the mask persists beyond target offset and attention is divided (Enns & Di Lollo, 1997, 2000). This masking effect, referred to as common onset masking, reflects reentrant processing in the visual system and can best be explained with a theory of object substitution (Di Lollo, Enns, & Rensink, 2000). In the present experiments, we investigated whether Gestalt grouping variables would influence the strength of common onset masking. The results indicated that (1) masking was impervious to grouping by form, similarity of color, position, luminance polarity, and common region and (2) masking increased with the number of elements in the masking display.

The task-choice procedure provides a way for assessing whether stimuli are processed immediately upon presentation and in parallel with other cognitive operations. In this procedure, the task changes on a trial-by-trial basis and the cue informing participants about the task appears either before or simultaneously with the target, which is either degraded or clear. Of interest is whether the effect of stimulus clarity will disappear when the cue is presented simultaneously with the target, suggesting capacity-free processing, or whether the effect of stimulus clarity will remain, suggesting target processing is delayed. Besner and Care developed this procedure using nonword targets and found that phonological information was not extracted in parallel with deciphering the task cue. The current experiment examined whether phonological and orthographic information could be extracted from word and nonword stimuli in a capacity-free manner. Results indicate that in both tasks some processing does occur in a capacity-free manner when words are used but not when nonwords are used. These data may be consistent with interactive activation models which posit top-down lexical connections that facilitate the extraction of sublexical codes.