Control over attentional capture within 170 ms by long-term memory control settings: Evidence from the N2pc.

Observers adopt attentional control settings (ACSs) based on their goals that guide the capture of attention: Searched-for stimuli capture attention, and stimuli that are not searched for do not. While previous behavioural research indicates that observers can adopt long-term memory (LTM) ACSs (Giammarco et al. Visual Cognition, 24, 78-101, 2016), it seems surprising that representations in LTM could guide attention quickly enough to control attentional capture. To assess the claim that LTM ACSs exert control over early attentional orienting, we recorded electroencephalography while participants studied and searched for 30 target objects in an attention cueing task. Participants reported the studied target and ignored the preceding cues. To control for perceptual evoked responses, on each trial we presented two cue objects (one studied and one nonstudied). Even though participants were instructed to ignore the cues, studied cues produced the N2pc event-related potential, indicating early attentional orienting that was preferentially directed towards the studied cue versus the nonstudied cue. Critically, the N2pc was detectable within 170 ms, confirming that LTM ACSs rapidly control early capture. We propose an update to contemporary models of attentional capture to account for rapid attentional guidance by LTM ACSs.

Repetition enhances the effects of activated long-term memory.

Recent research indicates that visual long-term memory (vLTM) representations directly interface with perception and guide attention. This may be accomplished through a state known as activated LTM, however, little is known about the nature of activated LTM. Is it possible to enhance the attentional effects of these activated representations? And furthermore, is activated LTM discrete (i.e., a representation is either active or not active, but only active representations interact with perception) or continuous (i.e., there are different levels within the active state that all interact with perception)? To answer these questions, in the present study, we measured intrusion effects during a modified Sternberg task. Participants saw two lists of three complex visual objects, were cued that only one list was relevant for the current trial (the other list was, thus, irrelevant), and then their memory for the cued list was probed. Critically, half of the trials contained repeat objects (shown 10 times each), and half of the trials contained non-repeat objects (shown only once each). Results indicated that repetition enhanced activated LTM, as the intrusion effect (i.e., longer reaction times to irrelevant list objects than novel objects) was larger for repeat trials compared with non-repeat trials. These initial findings provide preliminary support that LTM activation is continuous, as the intrusion effect was not the same size for repeat and non-repeat trials. We conclude that researchers should repeat stimuli to increase the size of their effects and enhance how LTM representations interact with perception.

Getting it right from the start: Attentional control settings without a history of target selection.

Observers can adopt attentional control settings that regulate how their attention is drawn to salient stimuli in the environment. Do observers choose their attentional control settings voluntarily, or are they primed in a bottom-up manner based on the stimuli that the observer has recently attended and responded to (i.e., target-selection history)? In the present experiment, we tested these two accounts using a long-term memory attentional control settings paradigm, in which participants memorized images of 18 common visual objects, and then searched for those objects in a spatial blink task. Unbeknownst to participants, we manipulated priming by dividing the set of target objects into two subsets: nine objects appeared frequently as targets in the spatial blink task (frequently primed objects), and nine infrequently (infrequently primed objects). We assessed attentional capture by presenting these objects as distractors in the spatial blink task and measuring their effect on task accuracy. We found that both subsets of objects captured attention more than non-studied objects, and frequently primed objects did not capture attention more than infrequently primed objects. Moreover, a follow-up analysis revealed that all studied objects captured attention, even before those objects had appeared as targets in the spatial blink task. These findings suggest that priming through target-selection history plays little-to-no role in long-term memory attentional control settings. Rather, these findings align with a growing body of evidence that attentional control settings are primarily implemented through voluntary control.

No role for activated long-term memory in attentional control settings.

Visual spatial attentional capture is contingent on an observer's goals, or attentional control settings. Recent research has demonstrated that observers can adopt attentional control settings based on numerous visual objects represented in episodic long-term memory (LTM). But why do LTM representations that comprise an attentional control set bias attentional capture, when other LTM representations do not? In the present study, we tested the activated LTM account-that LTM representations form an attentional control set if, and only if, they are represented in activated LTM-by mixing a working memory task to test for representation in activated LTM, with a spatial blink task to test for the state of participants' attentional control settings. In Experiments 1 and 2, inducing participants to represent complex visual objects in activated LTM did not result in those objects forming an attentional control set. In Experiment 3, we found a dissociation between activated LTM and attentional control settings; objects that were represented in activated LTM produced greater intrusion effects (indicating representation in activated LTM) than objects that were part of an attentional control set, yet smaller capture effects. These results do not support the activated LTM account. We conclude that representation in activated LTM is not the factor that determines which LTM representations comprise an attentional control set, and discuss the implications of these findings for research on attentional templates and hybrid visual and memory search. (PsycINFO Database Record (c) 2020 APA, all rights reserved).