Oculomotor capture by search-irrelevant features in visual working memory: on the crucial role of target–distractor similarity

Abstract

When searching for varying targets in the environment, a target template has to be maintained in visual working memory (VWM). Recently, we showed that search-irrelevant features of a VWM template bias attention in an object-based manner, so that objects sharing such features with a VWM template capture the eyes involuntarily. Here, we investigated whether targetdistractor similarity modulates capture strength. Participants saccaded to a target accompanied by a distractor. A single feature (e.g., shape) defined the target in each trial indicated by a cue, and the cue also varied in one irrelevant feature (e.g., color). The distractor matched the cue's irrelevant feature in half of the trials. Nine experiments showed that target-distractor similarity consistently influenced the degree of oculomotor capture. High target-distractor dissimilarity in the search-relevant feature reduced capture by the irrelevant feature (Experiments 1, 3, 6, 7). However, capture was reduced by high target-distractor similarity in the search-irrelevant feature (Experiments 1, 4, 5, 8). Strong oculomotor capture was observed if target-distractor similarity was reasonably low in the relevant and high in the irrelevant feature, irrespective of whether color or shape were relevant (Experiments 2 and 5). These findings argue for involuntary and object-based, top-down control by VWM templates, whereas its manifestation in oculomotor capture depends crucially on target-distractor similarity in relevant and irrelevant feature dimensions of the search object.

Memory-driven capture occurs for individual features of an object

“…Specifically, while the matching color may more easily stand-out among non-matching colors due to top-down salience attached to this color, the matching orientation might not be as distinguishable among non-matching orientations. This is consistent with stronger guidance for features that are more distinct [51][52][53][54] .…”

Visual working memory and action: Functional links and bi-directional influences

“…The functional links between visual working memory and action discussed above are at the heart of this review. Complementary mutual influences that one may describe as “involuntary” or “non-adaptive” – and in some cases “automatic” (but see Carlisle & Woodman, 2011 ; Foerster & Schneider, 2020 ; Neumann, 1984 ; Olivers et al, 2011 ) – are also informative. The rationale is as follows: if visual working memory and action are fundamentally intertwined in the brain, then these two functions should influence each other, even when such influences are not adaptive to the laboratory task at hand.…”

“…The content of visual working memory can involuntarily affects our actions ( Figure 1 (a), route IV), with the vast majority of evidence for this to date coming from oculomotor behaviour. For example, task-irrelevant visual inputs whose features (e.g., colour) match the content of visual working memory have been shown to capture attention and to affect eye movements toward them (Bahle et al, 2018 ; Beck et al, 2012 ; Foerster & Schneider, 2020 ; Hollingworth & Luck, 2009 ; Olivers et al, 2006 ; Soto et al, 2006 ) – especially when these representations are in a “prioritised state” ready for upcoming use (de Vries et al, 2020 ; Olmos-Solis et al, 2017 ; van Loon et al, 2017 ). Saccade trajectories too have been shown to be affected by the contents of visual working memory.…”

Attentional guidance by irrelevant features depends on their successful encoding into working memory.

“…The guidance by integrated feature templates was observed not only for saccadic responses (Foerster & Schneider, 2018), but also for perceptual judgments (Foerster & Schneider, 2019) and mouse clicks (Kerzel & Andres, 2020). The relevant and irrelevant dimensions (i.e., color and shape) can be selected arbitrarily, but with the limitation that features on the relevant dimension are less discriminable than features on the irrelevant dimension (Foerster & Schneider, 2020).…”

“…Evidence for the object-based guidance of attention with integrated feature templates was provided by Foerster and Schneider (2018, 2019, 2020). Foerster and Schneider asked their participants to memorize a target shape that was presented at the beginning of the trial.…”