Is there a trade-off between central (working memory) load and peripheral (perceptual) processing? To address this question, participants were requested to undertake an n-back task in one of two levels of central/cognitive load (i.e., 1-back or 2-back) in the presence of a to-be-ignored story presented via headphones. Participants were told to ignore the background story, but they were given a surprise memory test of what had been said in the background story, immediately after the n-back task was completed. Memory was poorer in the high central load (2-back) condition in comparison with the low central load (1-back) condition. Hence, when people compensate for higher central load, by increasing attentional engagement, peripheral processing is constrained. Moreover, participants with high working memory capacity (WMC)—with a superior ability for attentional engagement—remembered less of the background story, but only in the low central load condition. Taken together, peripheral processing—as indexed by incidental memory of background speech—is constrained when task engagement is high.

A long lasting debate in selective attention research revolves around the issue of whether irrelevant information is filtered at an early/perceptual processing stage or at a late/cognitive processing stage. Another long lasting debate concerns whether selective attention depends on a single, multi-purpose processing resource or whether it depends on several, independent processing resources. As a reaction to both debates, we have proposed a unified view of attention (Sörqvist, Stenfelt, & Rönnberg, 2012) whereby central/cognitive load modulates peripheral/perceptual processing. Moreover, the unified view of attention embodies a domain-general processing resource – called working memory capacity – that determines people’s capability for attentional/cognitive engagement. Here, we will present data from a recent experiment designed to critically examine this model. Participants undertook a visual-verbal version of the n-back task in various taskdifficulty conditions. Cortical processing of a background sound was measured with an fMRI protocol and individual differences in working memory capacity were measured with a package of three complex-span tasks. Our hypothesis is that higher task difficulty (in the n-back task) will be associated with increased prefrontal cortical activity and decreased auditory-temporal activity. Moreover, the magnitude of this effect should be related to individual differences in working memory capacity.

Two experiments investigated reactive top-down cognitive control of the detrimental influence of spoken distractors semantically related to visually-presented words presented for free recall.  

Experiment 1 demonstrated that an increase in focal task-engagement—promoted experimentally by reducing the perceptual discriminability of the visual target-words—eliminated the disruption by such distracters of veridical recall and also attenuated the erroneous recall of the distracters. A recall instruction that eliminates the requirement for output-monitoring was used in Experiment 2 to investigate whether increased task-engagement shields against distraction through a change in output-monitoring processes (back-end control) or by affecting the processing of the distracters during their presentation (front-end control). Rates of erroneous distracter-recall were much greater than in Experiment 1 but both erroneous distracter-recall and the disruptive effect of distracters on veridical recall were still attenuated under reduced target-word discriminability. Taken together, the results show that task-engagement is under dynamic strategic control and can be modulated to shield against auditory distraction by attenuating distracter-processing at encoding thereby preventing distracters from coming to mind at test.

Performance on visual-verbal tasks is generally impaired by task-irrelevant background speech, which can have consequences for individuals who works in noisy environments (e.g., schools or offices). This study examined the role increased task difficulty plays in shielding against the effects of background speech. This issue was addressed across 4 experiments whereby the level of task difficulty on visual-verbal tasks was manipulated (e.g., by changing the font of a text to one that is harder to read). Experiments 1 to 3 qualified the general finding: that background speech impairs performance on visual-verbal tasks (proofreading and prose memory), but only when task difficulty was low, not when it was high. Moreover, experiment 4 demonstrates that higher task difficulty on the focal task (n-back) also reduces recall on a surprise memory test on the content of a to-be-ignored background story. These results suggest that an increase in task difficulty, which promotes greater task engagement, can shield against the detrimental effects of background speech and also constrain the processing of complex semantic information present in background speech. 

In this article, we outline our view of how concentration shields against distraction. We argue that higher levels of concentration make people less susceptible to distraction for two reasons. One reason is that the undesired processing of the background environment is reduced. For example, when people play a difficult video game, as opposed to an easy game, they are less likely to notice what people in the background are saying. The other reason is that the locus of attention becomes more steadfast. For example, when people are watching an entertaining episode of their favorite television series, as opposed to a less absorbing show, attention is less likely to be diverted away from the screen by a ringing telephone. The theoretical underpinnings of this perspective, and potential implications for applied settings, are addressed.

In this paper, we apply the basic idea of a trade-off between the level of concentration and distractibility to test whether a manipulation of task difficulty can shield against distraction. Participants read, either in quiet or with a speech noise background, texts that were displayed either in an easy-to-read or a hard-to-read font. Background speech impaired prose recall, but only when the text was displayed in the easy-to-read font. Most importantly, recall was better in the background speech condition for hard-to-read than for easy-to-read texts. Moreover, individual differences in working memory capacity were related to the magnitude of disruption, but only in the easy-to-read condition. Making a task more difficult can sometimes facilitate selective attention in noisy work environments by promoting focal-task engagement. 

This article reports 2 experiments that examine techniques to shield against the potentially disruptive effects of task-irrelevant background speech on proofreading. The participants searched for errors in texts that were either normal (i.e., written in Times New Roman font) or altered (i.e., presented either in Haettenschweiler font or in Times New Roman but masked by visual noise) in 2 sound conditions: a silent condition and a condition with background speech. Proofreading for semantic/contextual errors was impaired by speech, but only when the text was normal. This effect of speech was completely abolished when the text was written in an altered font (Experiment 1) or when it was masked by visual noise (Experiment 2). There was no functional difference between the 2 ways to alter the text with regard to the way the manipulations influenced the effects of background speech on proofreading. The results indicate that increased task demands, which lead to greater focal-task engagement, may shield against the distracting effects of background speech on proofreading. 

This paper reviews the current literature on individual differences in susceptibility to the effects of background sound on visual-verbal task performance. A large body of evidence suggests that individual differences in working memory capacity (WMC) underpin individual differences in susceptibility to auditory distraction in most tasks and contexts. Specifically, high WMC is associated with a more steadfast locus of attention (thus overruling the call for attention that background noise may evoke) and a more constrained auditory-sensory gating (i.e., less processing of the background sound). The relation between WMC and distractibility is a general framework that may also explain distractibility differences between populations that differ along variables that covary with WMC (such as age, developmental disorders, and personality traits). A neurocognitive task-engagement/distraction trade-off (TEDTOFF) model that summarizes current knowledge is outlined and directions for future research are proposed.