Exploring the Nature of Memory Representations Underlying Priming of Pop-out in Visual Search
Bilge, Mustafa Taha
Participants respond to the target stimulus faster in a visual search task when the target item “pops out” among distractor stimuli. Priming of pop-out refers to cases in which repetition of the pop-out feature (e.g., color) from the previous trials further speeds up visual search. Previous attempts at characterizing the memory representations underlying priming of pop-out put forward a specialized memory system evolved to benefit from the repetition of pop-out feature and location of stimuli in the environment (Maljkovic & Nakayama, 1994, 1996). In this dissertation, I primarily used behavioral measures (e.g., reaction time, RT) and event-related potentials (ERPs) (e.g., P3b) associated with working and long-term memory to demonstrate that priming of pop-out could be explained by these canonical memory systems. The results suggest that working memory representations guide attention and this guidance is modulated by the number of distractors. However, sequential repetitions of the pop-out feature modulate both long-term memory and working memory representations and these representations are strategically employed in guidance of attention. Further, repetition of target locations does not modulate either working or long-term memory representations; therefore different memory systems are employed for priming of the pop-out feature and location. Taken together, these results suggest that canonical memory systems, such as working memory and long-term memory, could explain priming of pop-out in particular and memory effects from previous trials that could permeate through the current trial in other visual search tasks in general.