Dissociating compatibility effects and distractor costs in the additional singleton paradigm

Visual-cortical enhancement by acoustic distractors: The effects of endogenous spatial attention and visual working memory load

Past work has shown that when a peripheral sound captures our attention, it activates the contralateral visual cortex as revealed by an event-related potential component labelled the auditory-evoked contralateral occipital positivity (ACOP). This cross-modal activation of the visual cortex has been observed even when the sounds were not relevant to the ongoing task (visual or auditory), suggesting that peripheral sounds automatically activate the visual cortex. However, it is unclear whether top-down factors such as visual working memory (VWM) load and endogenous attention, which modulate the impact of task-irrelevant information, may modulate this spatially-specific component. Here, we asked participants to perform a lateralized VWM task (change detection), whose performance is supported by both endogenous spatial attention and VWM storage. A peripheral sound that was unrelated to the ongoing task was delivered during the retention interval. The amplitude of sound-elicited ACOP was analyzed as a function of the spatial correspondence with the cued hemifield, and of the memory array set-size. The typical ACOP modulation was observed over parieto-occipital sites in the 280-500 ms time window after sound onset. Its amplitude was not affected by VWM load but was modulated when the location of the sound did not correspond to the hemifield (right or left) that was cued for the change detection task. Our results suggest that sound-elicited activation of visual cortices, as reflected in the ACOP modulation, is unaffected by visual working memory load. However, endogenous spatial attention affects the ACOP, challenging the hypothesis that it reflects an automatic process.

Diminishing sensitivity and absolute difference in value-driven attention

Kim and Beck (2020b) demonstrated that value-driven attention is based on relative value rather than absolute value, suggesting that prospect theory is relevant to our understanding of value-driven attention. To further this understanding, the present study investigated the impacts of diminishing sensitivity on value-driven attention. According to diminishing sensitivity, changes in outcomes have greater impacts nearer the reference point of 0 than farther from the point. Thus, the difference between $1 and $100 looms larger than that between $901 and $1000, due to their different ratios (100/1 > 1000/901). However, according to the absolute difference hypothesis, the differences should have similar impacts due to the absolute differences being the same (100 – 1 = 1000 – 901). Experiment 1 investigated whether diminishing sensitivity operates in the modified value-driven attention paradigm while controlling the impact of absolute differences. In the training phase, 100-point and 1000-point color targets had references of 1-point and 901-point color targets, respectively. In the test phase, 100-point color distractors attracted attention more than 1000-point color distractors, supporting the diminishing sensitivity hypothesis. Experiment 2 examined the absolute difference hypothesis while controlling the impact of diminishing sensitivity. Contrary to the absolute difference hypothesis, the test phase showed that 1000-point color distractors (compared with 10-point colors for a 990 absolute difference in the training phase) failed to attract attention more than 100-point color distractors (compared with 1-point colors, for a 99 absolute difference). These results suggest that diminishing sensitivity rather than absolute difference influences value-driven attention, further supporting the relevance of prospect theory to value-driven attention.

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.

Reward history modulates perceptual load effects

The reward history of a stimulus can yield strong attentional selection biases. Indeed, attentional capture can be triggered by previously rewarded items which are neither salient nor relevant for the ongoing task, even when selection is clearly counter-productive to actually obtain the reward outcome. Therefore, value-driven attentional capture (VDAC) has been argued to be an automatic attention mechanism. Our study aimed at putting the VDAC automaticity directly to the test. For this purpose, the Load Theory offers a comprehensive framework where distraction is observed under low but not high perceptual load condition. Nevertheless, if VDAC is indeed automatic, distraction by reward-stimuli should be observed on both perceptual load conditions. We used a feature vs. conjunction discrimination of a go/no-go cue to manipulate perceptual load. As expected, our results revealed that perceptual load decreased interference produced by low-reward distractor. However, this effect was not significant for high-reward distractor, giving support to VDAC automaticity. We discussed our results in light of the Load Theory literature and we strongly encourage to consider reward history along with perceptual load in determining attentional capture.

Detection costs and contingent attentional capture

Peripheral cues reduce reaction times (RTs) to targets at the cued location with short cue-target SOAs (cueing benefits) but increase RTs at long SOAs (cueing costs or inhibition of return). In detection tasks, cueing costs occur at shorter SOAs and are larger compared with identification tasks. To account for effects of task, detection cost theory claims that the integration of cue and target into an object file makes it more difficult to detect the target as a new event, which is the principal task-requirement in detection tasks. The integration of cue and target is expected to increase when cue and target are similar. We provided evidence for detection cost theory in the modified spatial cueing paradigm. Two types of cues (onset, color) were paired with two types of targets (onset, color) in separate blocks of trials. In the identification task, we found cueing benefits with matching (i.e., similar) cue-target pairs (onset-onset, color-color) and no cueing effects with nonmatching cue-target pairs (onset-color, color-onset), which replicates previous work. In the detection task, cueing effects with matching cues were reduced and even turned into cueing costs for onset cues with onset targets, suggesting that cue-target integration made it more difficult to detect targets at the cued location as new events. In contrast, the results for nonmatching cue-target pairs were not affected by task. Furthermore, the pattern of false alarms in the detection task provides a measure of similarity that may explain the size of cueing benefits and costs.

Effect of task set-modulating attentional capture depends on the distractor cost in visual search: evidence from N2pc

Previous studies have confirmed that attention can be modulated by the current task set while involuntarily captured by salient items. However, little is known on which factors the modulation of attentional capture is dependent on when the same stimuli with different task sets are presented. In the present study, participants conducted two visual search tasks with the same search arrays by varying target and distractor settings (color singleton as target, onset singleton as distractor, named as color task, and vice versa). Ipsilateral and contralateral color distractors resulted in two different relative saliences in two tasks, respectively. Both reaction times (RTs) and N2-posterior-contralateral (N2pc) results showed that there was no difference between ipsilateral and contralateral color distractors in the onset task. However, both RTs and the latency of N2pc showed a delay to the ipsilateral onset distractor compared with the contralateral onset distractor. Moreover, the N2pc observed under the contralateral distractor condition in the color task was reversed, and its amplitude was attenuated. On the basis of these results, we proposed a parameter called distractor cost (DC), computed by subtracting RTs under the contralateral distractor condition from the ipsilateral condition. The results suggest that an enhanced DC might be related to the modification of N2pc in searching for the color target. Taken together, these findings provide evidence that the effect of task set-modulating attentional capture in visual search is related to the DC.