Mechanisms of priming of pop-out: Stored representations or feature-gain modulations?

Abstract

Previous research has shown that repetition of a task-relevant attention-capturing feature facilitates popout search. This priming of pop-out effect is due to some residual memory from recent trials. We explore two possible mechanisms of priming of pop-out: a top-down attentional benefit from a memory of the previous target representation that is stored in visual short-term memory (VSTM) and a bottom-up change of attentional gains from perceptual features of the previously attended target. We manipulated participants' ability to form a memory trace in VSTM by occupying it with a distractor task and found that occupying VSTM did not interfere with priming of pop-out. We next manipulated attentional gains associated with feature values by inserting an irrelevant task between pop-out searches. We found that the color of the target from the intervening perceptual task influenced pop-out search: The current pop-out search was facilitated when the intervening task's target matched the target color of the pop-out search. These results suggest that priming of pop-out might not be due to a memory trace of the previous targets in VSTM but, rather, might be due to changes in attentional control based on priming from relatively low-level feature representations of previously attended objects.

Exploring the contributions of spatial and non-spatial working memory to priming of pop-out

“…Experiment 1A replicated the findings from Lee et al (2009): The magnitude of PoP was not influenced by a concurrent non-spatial VWM task. More importantly, Experiment 1B demonstrated that the magnitude of PoP decreased when spatial VWM was loaded.…”

“…Experiment 1 was designed as a replication and extension of Lee et al's (2009) study. In Experiment 1A, we loaded nonspatial VWM while participants performed a color-oddball task in the periphery, and in Experiment 1B, we simply changed the load to a spatial VWM load.…”

“…Furthermore, despite Lee et al's (2009) finding, VWM may still play a role in PoP, because not all types of representations stored in VWM were investigated in that study. Baddeley and Hitch (1974;Baddeley, 2000;Baddeley & Logie, 1999) proposed a multicomponent model of working memory, which postulates that a memory is composed of subdivisions of specified functions-such as the phonological loop, episodic buffer, and visuospatial sketchpad.…”

“…Concerning the allocation of attention to each item, it has also been proposed that the template of target representation would be stored in VWM, and that it would bias attention in favor of the processing of an item similar to the target's representation (Desimone & Duncan, 1995;Duncan & Humphreys, 1989). Lee et al (2009;see also Mozer, Shettel, & Vecera, 2006) directly investigated whether VWM plays a role in PoP, by adopting a dual-task paradigm. In their experiments, participants were asked to maintain four colored patches in VWM while they performed a color-oddball search task.…”

“…This result indicates that a spatial VWM task exclusively impaired search because maintaining the spatial locations presented in the VWM task impaired spatial attention. Lee et al (2009) only tested the influence of loading nonspatial VWM on PoP, and did not investigate the possible effects of loading spatial VWM. Their rationale was that loading VWM would significantly decrease PoP if VWM was the mechanism responsible for PoP.…”