Attentional Capture From Inside vs. Outside the Attentional Focus

In this study, we jointly reported in an empirical and a theoretical way, for the first time, two main theories: Lavie’s perceptual load theory and Gaspelin et al.’s attentional dwelling hypothesis. These theories explain in different ways the modulation of the perceptual load/task difficulty over attentional capture by irrelevant distractors and lead to the observation of the opposite results with similar manipulations. We hypothesized that these opposite results may critically depend on the distractor type used by the two experimental procedures (i.e., distractors inside vs. outside the attentional focus, which could be, respectively, considered as potentially relevant vs. completely irrelevant to the main task). Across a series of experiments, we compared both theories within the same paradigm by manipulating both the perceptual load/task difficulty and the distractor type. The results were strongly consistent, suggesting that the influence of task demands on attentional capture varies as a function of the distractor type: while the interference from (relevant) distractors presented inside the attentional focus was consistently higher for high vs. low load conditions, there was no modulation by (irrelevant) distractors presented outside the attentional focus. Moreover, we critically analyzed the theoretical conceptualization of interference using both theories, disentangling important outcomes for the dwelling hypothesis. Our results provide specific insights into new aspects of attentional capture, which can critically redefine these two predominant theories.

Computational Neuroimaging of Cognition-Emotion Interactions: Affective and Task-similar Interference Differentially Impact Working Memory

Cognition depends on resisting interference and responding to relevant stimuli. Distracting information, however, varies based on content, requiring distinct filtering mechanisms. For instance, affective information captures attention, disrupts performance and attenuates activation along frontal-parietal regions during cognitive engagement, while recruiting bottom-up regions. Conversely, distraction matching task features (i.e. task-similar) increases fronto-parietal activity. Neural mechanisms behind unique effects of different distraction on cognition remain unknown. Using fMRI in 45 adults, we tested whether affective versus task-similar interference show distinct signals during delayed working memory (WM). We found robust differences between distractor types along fronto-parietal versus affective-ventral neural systems. We studied a hypothesized mechanism of this effect via a biophysically-based computational WM model that implements a functional antagonism between affective/cognitive neural 'modules'. This architecture reproduced experimental effects: task-similar distractors increased, whereas affective distractors attenuated cognitive module activity while increasing affective module signals. The model architecture suggested that task-based connectivity may be altered in affective-ventral vs. fronto-parietal networks depending on distractor type. Empirically, affective interference significantly increased connectivity within the affective-ventral network, but reduced connectivity between affective-ventral and fronto-parietal networks, which predicted WM performance. These findings detail an antagonistic architecture between cognitive and affective systems, capable of flexibly engaging distinct distractions during cognition.

Polarity-dependent Effects of Biparietal Transcranial Direct Current Stimulation on the Interplay between Target Location and Distractor Saliency in Visual Attention

Visual attention allows the allocation of limited neural processing resources to stimuli based on their behavioral priorities. The selection of task-relevant visual targets entails the processing of multiple competing stimuli and the suppression of distractors that may be either perceptually salient or perceptually similar to targets. The posterior parietal cortex controls the interaction between top–down (task-driven) and bottom–up (stimulus-driven) processes competing for attentional selection, as well as spatial distribution of attention. Here, we examined whether biparietal transcranial direct current stimulation (tDCS) would modulate the interaction between top–down and bottom–up processes in visual attention. Visual attention function was assessed with a visual discrimination task, in which a lateralized target was presented alone or together with a contralateral, similar or salient, distractor. The accuracy and RTs were measured before and during three stimulation sessions (sham, right anodal/left cathodal, left anodal/right cathodal). The analyses demonstrated (i) polarity-dependent effects of tDCS on the accuracy of target discrimination, but only when the target was presented with a similar distractor; (ii) the tDCS-triggered effects on the accuracy of discriminating targets, accompanied by a similar distractor, varied according to the target location; and (iii) overall detrimental effects of tDCS on RTs were observed, regardless of target location, distractor type, and polarity of the stimulation. We conclude that the observed polarity, distractor type, and target location-dependent effects of biparietal tDCS on the accuracy of target detection resulted from both a modulation of the interaction between top–down and bottom–up attentional processes and the interhemispheric competition mechanisms guiding attentional selection and spatial deployment of attention.

Eye movements as indicator of solution knowledge in anagram solving

The current study attempted to replicate the results of Ellis et al. (2011) in an extended way. In the original study Ellis et al. demonstrated that eye movements may indicate the solution knowledge prior to response. They compared viewing times on the distractor letter vs. solution letters. Viewing time on distractor letter started decreasing since several seconds prior to response both in insight and non-insight trials. We added two additional parameters of anagrams: solution-word frequency and frequency of cooccurrence (“agglutination”) of the distractor letter with the solution letters. Low-frequency words and/or stimuli with high agglutinating distractor were solved less often and longer than others, with the effect of distractor type only for the low-frequency words. Eye-tracking data analysis revealed that either in insight and non-insight trials distractor did not differ from solution letters in the first half of the solving process, but had fewer viewing time in the second half of the solving process. In the more difficult stimuli (by solution- word frequency and distractor type) distractor was revealed later than in easier ones or did not differ at all. Eye-tracking data on viewing time on distractor vs. solution letters were in accordance with the Ellis et al.’s results and the anagram difficulty factors.

Impact of Quality of the Image, Orientation, and Similarity of the Stimuli on Visual Search for Faces

Evidence from a series of visual-search experiments suggests that detecting an upright face amidst face-like distractors elicits a pattern of reaction times that is consistent with serial search. In four experiments the impact of orientation, number of stimuli in the display, and similarity of stimuli on search rates was examined. All displays were homogeneous. Trials were blocked by distractor type for three experiments. In the first experiment search rates for faces amidst identical faces rotated by 180° were examined. No advantage was evidenced in searching for an upright face. The impact of the quality of the face representation was examined in the second experiment. Search rates are reported for a line-drawn and a digitized image of a face amidst identical faces rotated by 180°. Search was faster for digitized than for line-drawn faces. The findings of the first experiment for orientation were replicated. In the third and fourth experiments the impact of disrupting the facial configuration in distractors was examined and performance was contrasted for blocked and mixed trials, respectively, with the same stimulus set. Reaction times increased with the number of distractors in the display in all but the nonface condition, which produced a shallow slope suggestive of parallel search. Search amidst other distractors appeared to involve the conjoining of a specific set of features with specific spatial relations. The hierarchy of relevant configural dimensions was inconsistent across these two experiments, suggesting that the symmetry, top-down order of features, orientation of the face, and predictability of the distractor type may have an interactive effect on search strategies.

Distractor Ratio and Grouping Processes in Visual Conjunction Search

According to feature integration theory, conjunction search is conducted via a serial self-terminating search. However, effects attributed to search processes operating on the entire display may actually reflect search restricted to elements defined by a single feature. In experiment 1 this question is addressed in a reaction-time (RT) paradigm by varying distractor ratios within an array of fixed size. For trials in which the target was present in the array, RT functions were roughly symmetric, the shortest RTs being for extreme distractor ratios, and the longest RTs being for arrays in which there were an equal number of each distractor type. This result is superficially consistent with Zohary and Hochstein's interpretation that subjects search for only one distractor type and are able to switch search strategy from trial to trial. However, negative-trial data from experiment 1 cast doubt on this interpretation. In experiment 2 the possible role of ‘pop out’ and of distractor grouping in visual conjunction search is investigated. Results of experiment 2 suggest that grouping may play a more important role than does distractor ratio, and point to the importance of the spatial layout of the target and of the distractor elements in visual conjunction search. Results of experiment 2 also provide clear evidence that groups of spatially adjacent homogeneous elements may be processed as a unit.