Abstract
What is the mechanism that underlies contextual cueing? The effect was initially thought to be the product of memory for the repeated context guiding attention to the target location. Recent work has disputed this explanation pointing to the absence of decreased search slopes (derived from Response Time x Set Size functions) in contextual cueing, a criterion used for establishing the presence of attentional guidance in standard search. However, we argue that the candidate source of guidance in contextual cueing – memory for the repeated displays – is fundamentally different than that of standard search tasks. It is this difference, rather than a lack of attentional guidance, that explains the failure to observe decreased search slopes in contextual cueing. While the quality of guidance derived from feature dimensions of the display in standard search is constant across set sizes, as set size increases in a contextual cueing task, so does the burden on the memory system. I.e., the smaller set size displays are easier to remember and thus offer better quality guidance than the larger set sizes. To directly investigate the availability/strength of memory traces for the repeated displays we utilized a measure of interference in a standard contextual cueing task. After learning had occurred and the contextual cueing effect was present, the location of the target in each repeated display was changed. This manipulation resulted in increased mean response times (interference) in the repeated condition after the change. The magnitude of interference varied inversely with set size indicating that the availability of context memory is contingent upon the amount of information contained within the display. These findings indicate that a lack of decreased search slopes alone is insufficient to discount attentional guidance as the mechanism underlying contextual cueing.