Reversal of object-based benefits in visual attention

In divided-attention tasks, observers must make speeded (or near threshold accuracy) judgements concerning two target features in a display. Typically, when the two features belong to the same object they are more rapidly judged than when they belong to separate objects, a pattern of findings referred to here as a “same-object benefit”. However, we note here that many of these studies share common features, in particular the use of pre-exposed, outline, and/or overlapping objects, and their findings may not generalize to other types of display. Building substantially on previous work by Davis, Welch, Holmes, and Shepherd (2001), we show in four new studies that once these features are not present in a divided-attention task, no same-object benefits are reported. Rather we now find “same-object costs”, where features belonging to a single object are less rapidly judged than features belonging to separate objects.