How visual working memory handles distraction: cognitive mechanisms and electrophysiological correlates

ABSTRACT

The ability to selectively encode relevant information (filtering ability) is crucial to make best use of the severely limited space that visual working memory (VWM) provides. This review considers why filtering ability is important, how it is measured, and it discusses how filtering might be implemented computationally at the cognitive and neuronal level. Based on theoretical considerations, we explore the possibility that filtering ability involves not only the suppression of irrelevant, but also the enhancement of relevant information – functions that might be implemented by different brain mechanisms; and we review behavioural and electrophysiological data in light of the various resulting model versions. We also highlight that filtering is better understood as coordinated brain network activity, rather than being the function of a single region. Broadcasting of control signals from prefrontal cortex appears critical in upholding information in posterior cortical areas in the absence of distractors. The very same ability might also support selective processing of relevant information in the presence of distractors. These ideas provide a novel explanation for the relation between filtering ability and VWM capacity and thereby (re-)establish a central role of filtering ability in general VWM functioning.

KEYWORDS:

• Selective attention
• biased competition
• executive functions
• neuronal networks
• brain oscillations

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 The present review focuses on the ability to disregard irrelevant information during encoding into VWM. There is also work on shielding already encoded VWM content from distraction occurring during the retention period of the task (e.g., Bonnefond & Jensen, 2012; Feredoes, Heinen, Weiskopf, Ruff, & Driver, 2011). We draw upon this work here only if respective studies on filtering during encoding are lacking. Owing to the present focus, we use the word filtering ability to refer to the ability to selectively encode task-relevant information while disregarding concurrently presented, irrelevant information (distraction).

2 Discrimination between targets and distractors can likely only be achieved by pro-active (i.e., before memory-display onset) tuning of posterior areas according to (frontally communicated) task goals. In a task where distractor presence is unpredictable (as in the Liesefeld et al., 2014, study), this tuning would occur on distractor-absent as well as distractor-present trials and does therefore not produce an effect of distractor presence. Purpose-designed studies are needed to examine this pro-active part of distractor handling (see Vissers, van Driel, & Slagter, 2016, for some indication that such a preparatory mechanism might be reflected in lateralised alpha).

Additional information

Funding

This work was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) under grant MU 773/16-2 (to H.J.M.), LI 2868/3-1 (to H.R.L.), SA 1782/2-2 (to P.S.) and JA 1999/5-1 (to S.N.J.), by the European Research Council (European Commission) under grant ERC StG MEMCIRCUIT (to S.N.J.), and by LMU Munich‘s Institutional Strategy LMUexcellent within the framework of the German Excellence Initiative (to H.J.M. and H.R.L.).