The location but not the attributes of visual cues are automatically encoded into working memory

Although it has been well known that visual cues affect the perception of subsequent visual stimuli, relatively little is known about how the cues themselves are processed. The present study attempted to characterize the processing of a visual cue by investigating what information about the cue is stored in terms of both location ("where" is the cue) and attributes ("what" are the attributes of the cue). In 11 experiments subjects performed several trials of reporting a target letter and then answered an unexpected question about the cue (e.g., the location, color, or identity of the cue). This surprise question revealed that participants could report the location of the cue even when the cue never indicated the target location and they were explicitly told to ignore it. Furthermore, the memory trace of this location information endured during encoding of the subsequent target. In contrast to location, attributes of the cue (e.g., color) were poorly reported, even for attributes that were used by subjects to perform the task. These results shed new light on the mechanisms underlying cueing effects and suggest also that the visual system may create empty object files in response to visual cues.