Does the Attentional Boost Effect Depend on the Intentionality of Encoding? Investigating the Mechanisms Underlying Memory for Visual Objects Presented at Behaviorally Relevant Moments in Time

Abstract

Pictures in a rapid serial visual presentation (RSVP) stream are better remembered when they are simultaneously presented with targets of an unrelated detection task than when they are presented with distractors. However, it is unclear whether this so-called “attentional boost effect” depends on the intentionality of encoding. While there are studies suggesting that the attentional boost effect even occurs when encoding is incidental, there are several methodological issues with these studies, which may have undermined the incidental encoding instructions. The present study ( N = 141) investigated the role of the intentionality of encoding with an improved experimental design. Specifically, to prevent a spill-over of intentional resources to the pictures in the RSVP stream, the speed of the stream was increased (to four pictures per second) and each picture was presented only once during the course of the experiment. An attentional boost effect was only found when encoding was intentional but not when encoding was incidental. Interestingly, memory performance for incidentally encoded pictures was nevertheless substantially above chance, independently of whether images were presented with search-relevant targets or distractors. These results suggest that the attentional boost effect is a memory advantage that occurs only under intentional encoding conditions, and that perceptual long-term memory representations are formed as a natural product of perception, independently of the presence of behaviorally relevant events.

Grounding the Attentional Boost Effect in Events and the Efficient Brain

“…First, target detection does not reliably increase dualtask interference for ignored background images. This was true even when ignored images were presented very briefly and/ or only one time (e.g., Yebra et al, 2019;Broitman and Swallow, 2020;Hutmacher and Kuhbandner, 2020). Second, at the least, goal-directed attention to the background item increases the magnitude of the ABE (Swallow and Jiang, 2014a;Broitman and Swallow, 2020).…”

“…One factor that may account for the variety of effects of target detection on incidental memory is whether the images could be attended despite instructions to ignore them. As argued by Hutmacher and Kuhbandner (2020), the presence of an ABE for incidentally presented images may depend on how long, and how many times, they are presented. When participants were instructed to memorize the objects presented in 250 ms long trials, they showed a small memory advantage (~2%) for objects that appeared with a target.…”

“…This finding is consistent with an effect of temporal selection on early encoding processes. However, limiting the opportunity to encode an item too much may reduce or eliminate the ABE with visual materials: the ABE is weak when encoding time is limited to 250 ms (Hutmacher and Kuhbandner, 2020).…”

“…However, it also implies that, like the boundary advantage (Swallow et al, 2009, the ABE could incorporate information that is outside the current focus of attention. The results of studies investigating this issue have been mixed: some studies report a boost to ignored or task-irrelevant information (Dewald et al, 2013;Swallow and Jiang, 2014a;Walker et al, 2017;Turker and Swallow, 2019;Yebra et al, 2019;Broitman and Swallow, 2020), others report no effect of target detection on memory for ignored images (Swallow and Jiang, 2011;Leclercq and Seitz, 2012a;Hutmacher and Kuhbandner, 2020), and one study found poorer memory for ignored background words paired with targets (Dewald et al, 2011).…”

The attentional boost effect facilitates the encoding of contextual details: New evidence with verbal materials and a modified recognition task

“…This is an important departure from the study reported by Mulligan et al ( 2016 ), in which participants were only instructed to remember the words. While the use of intentional instructions does not represent an essential element for obtaining the ABE (the effect has been replicated with incidental instructions: Broitman & Swallow, 2020 ; Spataro et al, 2013 ; Swallow & Jiang, 2014 ; but see Hutmacher & Kuhbandner, 2020 ), it may be instead crucial for revealing the influence of target detection on contextual memory when using verbal materials. Specifically, Broitman and Swallow ( 2020 ) showed that both recollection and familiarity estimates were greater for target-paired faces than for distractor-paired faces, regardless of whether the faces were encoded incidentally or intentionally.…”