Investigating the suitability of online eye tracking for psychological research: Evidence from comparisons with in-person data using emotion-attention interaction tasks.

The future is bound to bring rapid methodological changes to psychological research. One such promising candidate is the use of webcam-based eye tracking. Earlier research investigating the quality of online eye-tracking data has found increased spatial and temporal error compared to infrared recordings. Our studies expand on this work by investigating how this spatial error impacts researchers' abilities to study psychological phenomena. We carried out two studies involving emotion-attention interaction tasks, using four participant samples. In each study, one sample involved typical in-person collection of infrared eye-tracking data, and the other involved online collection of webcam-based data. We had two main findings: First, we found that the online data replicated seven of eight in-person results, although the effect sizes were just 52% [42%, 62%] the size of those seen in-person. Second, explaining the lack of replication in one result, we show how online eye tracking is biased toward recording more gaze points near the center of participants' screen, which can interfere with comparisons if left unchecked. Overall, our results suggest that well-powered online eye-tracking research is highly feasible, although researchers must exercise caution, collecting more participants and potentially adjusting their stimulus designs or analytic procedures.

Complex background information slows down parallel search efficiency by reducing the strength of interitem interactions.

In the laboratory, visual search is often studied using uniform backgrounds. This contrasts with search in daily life, where potential search items appear against more complex backgrounds. In the present study, we examined the effects of background complexity on a parallel visual search under conditions where objects are easily segregated from the background. Target-distractor similarity was sufficiently low such that search could unfold in parallel, as indexed by reaction times that increase logarithmically with set size. The results indicate that when backgrounds are relatively simple (sandy beach with water elements), search efficiency is comparable to search using a solid background. When backgrounds are more complex (child bedroom or checkerboard), logarithmic search slopes increase compared to search on solid backgrounds, especially at higher levels of target-distractor similarity. The results are discussed in terms of different theories of visual search. It is proposed that the complex visual information occurring in between distractors slows down individual distractor rejection times by weakening the strength of interitem interactions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The impact of focused attention on emotional evaluation: An eye-tracking investigation.

Emotional well-being depends on the ability to successfully engage a variety of coping strategies to regulate affective responses. Most studies have investigated the effectiveness of emotion regulation (ER) strategies that are deployed relatively later in the timing of processing that leads to full emotional experiences (i.e. reappraisal and suppression). Strategies engaged in earlier stages of emotion processing, such as those involved in attentional deployment, have also been investigated, but relatively less is known about their mechanisms. Here, we investigate the effectiveness of self-guided focused attention (FA) in reducing the impact of unpleasant pictures on the experienced negative affect. Participants viewed a series of composite images with distinguishable foreground (FG, either negative or neutral) and background (BG, always neutral) areas and were asked to focus on the FG or BG content. Eye-tracking data were recorded while performing the FA task, along with participants' ratings of their experienced emotional response following the presentation of each image. First, proving the effectiveness of self-guided FA in down-regulating negative affect, focusing away from the emotional content of pictures (BG focus) was associated with lower emotional ratings. Second, trial-based eye-tracking data corroborated these results, showing that spending less time gazing within the negative FG predicted reductions in emotional ratings. Third, this reduction was largest among subjects who habitually use suppression to regulate their emotions. Overall, the present findings expand the evidence regarding the FA's effectiveness in controlling the impact of emotional stimuli and inform the development of training interventions emphasizing attentional control to improve emotional well-being. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Distractor-distractor interactions in visual search for oriented targets explain the increased difficulty observed in nonlinearly separable conditions.

The linear separability effect refers to a benefit in search performance observed in a feature-search task, where target and distractor features vary along a continuous feature dimension: Search performance is best when there is a boundary in feature space that separates the distractor features from the target feature. However, the role that distractor heterogeneity plays in this effect is not well understood. Here, we reexamined this effect in the context of a new predictive procedure from Lleras et al. (2019) that quantifies the impact of distractor heterogeneity on search performance. Experiments 1A and 1B measured people's performance in homogeneous search conditions where they searched for the target among one type of distractor. The parameters observed in Experiments 1A and B were then used to predict search times in Experiments 2 and 3, where the target was presented in heterogeneous displays containing two types of distractors. The results show that total variance accounted for was 95% to 98%, without including any factor indexing the linear separability rule. The results demonstrate that heterogeneous search in orientation space is a function of target-distractor similarity and interitem interactions. The study highlights the robustness of the predictive procedure and demonstrates the generalizability of the method to estimate interitem interactions to new stimulus types. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Irrelevant features of distractors in intervening visual search tasks cause active visual working memory interference - the more difficult the search task, the more interference it causes.

Visual working memory (VWM) content disrupts visual search performance when there is a singleton in the search array that is similar to the content in VWM, even when this singleton is task irrelevant. Typically, the memory-similar singleton captures attention, which results in slower search performance for memory-similar conditions compared to conditions where memory-similar content is absent. Recently, it has also been shown that VWM content may be affected when memory-similar stimuli are processed. Specifically, it appears that VWM representations bias toward memory-similar information that is processed but not memory-dissimilar information. Here, we test whether the bias caused by processing memory-similar information is an active interference process (growing with engagement with the memory-similar stimuli) or a passive interference process (indifferent to the engagement with memory-similar stimuli). To test this, observers were tasked with memorizing a single color followed by a search task. The search task was either easy or difficult, and the search items could either be memory-similar or memory-dissimilar. Critically, the target in the search task was defined by its shape, so the color of the search items was irrelevant to the search task. At the end of each trial, participants reported the color in memory using a continuous report color wheel. The results showed that VWM representations drifted towards the irrelevant color of the search items in the memory-similar conditions, and this effect was larger in the difficult search condition. The results provide evidence that VWM representations receive active interference from processing memory-similar stimuli.

Predicting how surface texture and shape combine in the human visual system to direct attention.

Objects differ from one another along a multitude of visual features. The more distinct an object is from other objects in its surroundings, the easier it is to find it. However, it is still unknown how this distinctiveness advantage emerges in human vision. Here, we studied how visual distinctiveness signals along two feature dimensions-shape and surface texture-combine to determine the overall distinctiveness of an object in the scene. Distinctiveness scores between a target object and distractors were measured separately for shape and texture using a search task. These scores were then used to predict search times when a target differed from distractors along both shape and texture. Model comparison showed that the overall object distinctiveness was best predicted when shape and texture combined using a Euclidian metric, confirming the brain is computing independent distinctiveness scores for shape and texture and combining them to direct attention.

Prioritization in visual attention does not work the way you think it does.

A common assumption in attention theories is that attention prioritizes search items based on their similarity to the target. Here, we tested this assumption and found it wanting. Observers searched through displays containing candidates (distractors that cannot be confidently differentiated from the target by peripheral vision) and lures (distractors that can be). Candidates had high or low similarity to the target. Search displays were either candidate-homogeneous (all items of same similarity) or candidate-heterogeneous (equal numbers of each similarity). Response times to candidate-heterogeneous displays were equivalent to the average of high- and low-similarity displays, suggesting that attention was allocated randomly, rather than toward the high-similarity candidates first. Lures added a response time cost that was independent of the candidates, suggesting they were rejected prior to candidates being inspected. These results suggest a "reverse" prioritization process: Distributed attention discards least target-similar items first, while focused spatial attention is randomly directed to target-similar items. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Correction to: A target contrast signal theory of parallel processing in goal-directed search.

During production of the article, Figure 4 was incorrectly used twice in the initial article, so it appeared both as Figure 4 and Figure 5 in the article.

A target contrast signal theory of parallel processing in goal-directed search.

Feature Integration Theory (FIT) set out the groundwork for much of the work in visual cognition since its publication. One of the most important legacies of this theory has been the emphasis on feature-specific processing. Nowadays, visual features are thought of as a sort of currency of visual attention (e.g., features can be attended, processing of attended features is enhanced), and attended features are thought to guide attention towards likely targets in a scene. Here we propose an alternative theory - the Target Contrast Signal Theory - based on the idea that when we search for a specific target, it is not the target-specific features that guide our attention towards the target; rather, what determines behavior is the result of an active comparison between the target template in mind and every element present in the scene. This comparison occurs in parallel and is aimed at rejecting from consideration items that peripheral vision can confidently reject as being non-targets. The speed at which each item is evaluated is determined by the overall contrast between that item and the target template. We present computational simulations to demonstrate the workings of the theory as well as eye-movement data that support core predictions of the theory. The theory is discussed in the context of FIT and other important theories of visual search.

Response interference by central foils is modulated by dimensions of depression and anxiety.

We used a maximum-likelihood-based model selection approach to investigate what aspects of affective traits influence flanker interference in a nonaffective task. A total of 153 undergraduates completed measures of anhedonic depression, anxious arousal, anxious apprehension, and a modified flanker task with two levels of perceptual load. For central foils, the most parsimonious model included load, depression, and anxious arousal. Participants scoring low on the depression and anxious arousal scales exhibited a typical perceptual load effect, with larger interference effects observed under low perceptual load compared with high perceptual load conditions. Increased depression symptoms were associated with a reduced perceptual load effect. However, the load effect reemerged in individuals who scored high on both depression and anxious arousal scales, but to a lesser extent than those scoring low on both. This pattern of results underscores the importance of studying co-occurring affective traits and their interactions in the same sample. For peripherally presented foils, the model that only included load as a factor was more parsimonious than any of the models incorporating affective traits. These findings suggest avenues for future research and highlight the role of diverse affective symptoms on various aspects of nonemotional attentional processing.

The impact of focused attention on subsequent emotional recollection: A functional MRI investigation.

In his seminal works, Endel Tulving argued that functionally distinct memory systems give rise to subjective experiences of remembering and knowing (i.e., recollection- vs. familiarity-based memory, respectively). Evidence shows that emotion specifically enhances recollection, and this effect is subserved by a synergistic mechanism involving the amygdala (AMY) and hippocampus (HC). In extreme circumstances, however, uncontrolled recollection of highly distressing memories may lead to symptoms of affective disorders. Therefore, it is important to understand the factors that can diminish such detrimental effects. Here, we investigated the effects of Focused Attention (FA) on emotional recollection. FA is an emotion regulation strategy that has been proven quite effective in reducing the impact of emotional responses associated with the recollection of distressing autobiographical memories, but its impact during emotional memory encoding is not known. Functional MRI and eye-tracking data were recorded while participants viewed a series of composite negative and neutral images with distinguishable foreground (FG) and background (BG) areas. Participants were instructed to focus either on the FG or BG content of the images and to rate their emotional responses. About 4 days later, participants' memory was assessed using the R/K procedure, to indicate whether they Recollected specific contextual details about the encoded images or the images were just familiar to them - i.e., participants only Knew that they saw the pictures without being able to remember specific contextual details. First, results revealed that FA was successful in decreasing memory for emotional pictures viewed in BG Focus condition, and this effect was driven by recollection-based retrieval. Second, the BG Focus condition was associated with decreased activity in the AMY, HC, and anterior parahippocampal gyrus for subsequently recollected emotional items. Moreover, correlation analyses also showed that reduced activity in these regions predicted greater reduction in emotional recollection following FA. These results demonstrate the effectiveness of FA in mitigating emotional experiences and emotional recollection associated with unpleasant emotional events.

Predicting how color and shape combine in the human visual system to direct attention.

Objects in a scene can be distinct from one another along a multitude of visual attributes, such as color and shape, and the more distinct an object is from its surroundings, the easier it is to find it. However, exactly how this distinctiveness advantage arises in vision is not well understood. Here we studied whether and how visual distinctiveness along different visual attributes (color and shape, assessed in four experiments) combine to determine an object's overall distinctiveness in a scene. Unidimensional distinctiveness scores were used to predict performance in six separate experiments where a target object differed from distractor objects along both color and shape. Results showed that there is mathematical law determining overall distinctiveness as the simple sum of the distinctiveness scores along each visual attribute. Thus, the brain must compute distinctiveness scores independently for each visual attribute before summing them into the overall score that directs human attention.

Fixed-target efficient search has logarithmic efficiency with and without eye movements.

Stage 1 processing in visual search (e.g., efficient search) has long been thought to be unaffected by factors such as set size or lure-distractor similarity (or at least to be only minimally affected). Recent research from Buetti, Cronin, Madison, Wang, and Lleras (Journal of Experimental Psychology: General, 145, 672-707, 2016) showed that in efficient visual search with a fixed target, reaction times increase logarithmically as a function of set size and, further, that the slope of these logarithmic functions is modulated by target-distractor similarity. This has led to the proposal that the cognitive architecture of Stage 1 processing is parallel, of unlimited capacity, and exhaustive in nature. Such an architecture produces reaction time functions that increase logarithmically with set size (as opposed to being unaffected by it). However, in the previous studies, eye movements were not monitored. It is thus possible that the logarithmicity of the reaction time functions emerged simply as an artifact of eye movements rather than as a reflection of the underlying cognitive architecture. Here we ruled out the possibility that eye movements resulted in the observed logarithmic functions, by asking participants to keep their eyes at fixation while completing fixed-target efficient visual search tasks. The logarithmic RT functions still emerged even when participants were not allowed to make eye movements, thus providing further support for our proposal. Additionally, we found that search efficiency is slightly improved when eye movements are restricted and lure-target similarity is relatively high.

Parallel, exhaustive processing underlies logarithmic search functions: Visual search with cortical magnification.

Our lab recently found evidence that efficient visual search (with a fixed target) is characterized by logarithmic Reaction Time (RT) × Set Size functions whose steepness is modulated by the similarity between target and distractors. To determine whether this pattern of results was based on low-level visual factors uncontrolled by previous experiments, we minimized the possibility of crowding effects in the display, compensated for the cortical magnification factor by magnifying search items based on their eccentricity, and compared search performance on such displays to performance on displays without magnification compensation. In both cases, the RT × Set Size functions were found to be logarithmic, and the modulation of the log slopes by target-distractor similarity was replicated. Consistent with previous results in the literature, cortical magnification compensation eliminated most target eccentricity effects. We conclude that the log functions and their modulation by target-distractor similarity relations reflect a parallel exhaustive processing architecture for early vision.

The role of crowding in parallel search: Peripheral pooling is not responsible for logarithmic efficiency in parallel search.

Recent results from our laboratory showed that, in fixed-target parallel search tasks, reaction times increase in a logarithmic fashion with set size, and the slope of this logarithmic function is modulated by lure-target similarity. These results were interpreted as being consistent with a processing architecture where early vision (stage one) processes elements in the display in exhaustive fashion with unlimited capacity and with a limitation in resolution. Here, we evaluate the contribution of crowding to our recent logarithmic search slope findings, considering the possibility that peripheral pooling of features (as observed in crowding) may be responsible for logarithmic efficiency. Factors known to affect the strength of crowding were varied, specifically: item spacing and similarity. The results from three experiments converge on the same pattern of results: reaction times increased logarithmically with set size and were modulated by lure-target similarity even when crowding was minimized within displays through an inter-item spacing manipulation. Furthermore, we found logarithmic search efficiencies were overall improved in displays where crowding was minimized compared to displays where crowding was possible. The findings from these three experiments suggest logarithmic efficiency in efficient search is not the result peripheral pooling of features. That said, the presence of crowding does tend to reduce search efficiency, even in "pop-out" search situations.

Attentional effect on contrast appearance: From enhancement to attenuation.

Does attention alter appearance? Recent studies have shown that an exogenous cue tends to increase the perceived contrast of a low-contrast stimulus. In the present study we systematically studied the attentional effect over a wide range of contrast levels (15% to 60%). Besides replicating the enhancement at lower contrast levels with higher comparative tasks (Experiment 1), the data revealed a cue-induced attenuation in apparent contrast at higher contrast levels with lower comparative tasks (Experiment 2) and same/different judgment task (Experiment 3). This attenuation effect was robust at the individual level, and it was not due to response bias or sensory interactions (Experiments 3 and 4). These results suggest that attention modulates contrast appearance and this effect depends on both the contrast level and the type of judgment task used. We propose that our findings can be understood through contrast gain mechanism on supersatuating neurons, whose response increases first as the stimulus intensity increases, but decrease the responses after the peak. This surprising phenomenon offers insights for the underlying neural mechanisms of visual processing. (PsycINFO Database Record

Can we "apply" the findings of Forster and Lavie (2008)? On the generalizability of attentional capture effects under varying levels of perceptual load.

Perceptual Load theory states that the degree of perceptual load on a display determines the amount of leftover attentional resources that the system can use to process distracting information. An important corollary of this theory is that the amount of perceptual load determines the vulnerability of the attention system to being captured by completely irrelevant stimuli, predicting larger amounts of capture with low perceptual load than with high perceptual load. This prediction was first confirmed by Forster and Lavie (2008). Here, we report 6 experiments that followed up on those earlier results, where we find that in many cases, the opposite pattern is obtained: attentional capture increased with increasing perceptual load. Given the lack of generalizability of the theory to new experimental contexts with fairly minor methodological differences, we conclude that Perceptual Load may not be a useful framework for understanding attentional capture. The theoretical and applied importance of these findings is discussed. In particular, we caution against using this theory in applied tasks and settings because best-use recommendations stemming from this theory regarding strategies to decrease distractibility may in fact produce the opposite effect: an increase in distractibility (with distractibility being indexed by the magnitude of the capture effect). (PsycINFO Database Record

Exploring the contributions of spatial and non-spatial working memory to priming of pop-out.

Priming of pop-out (PoP) refers to the facilitation of performance that occurs when a target-defining feature is repeated across consecutive trials in a pop-out oddball search task. The underlying mechanism of PoP has been poorly understood and raises important questions about how our visual system is guided by past experiences, even during bottom-up processing. Lee, Mozer, and Vecera (Attention, Perception, & Psychophysics, 71, 1059-1071, 2009) demonstrated that PoP remained unaffected by a concurrent non-spatial visual working memory (VWM) load, and they concluded that PoP occurs through feature gain modulation, essentially eliminating the contribution of memory representations in VWM to PoP. In the present study, we followed up on those results by (a) replicating the null effect of non-spatial VWM load on PoP and (b) examining the effect of spatial VWM load on PoP. The results showed that spatial VWM load does interfere with PoP, supporting the notion that spatial VWM is involved in PoP. In Experiment 2, we extended this finding by manipulating VWM load and observing its consequence on the magnitude of PoP. Increasing spatial VWM load decreased the amount of PoP observed, in a dose-dependent manner, whereas changes in non-spatial VWM load did not. Contrary to Lee et al.'s conclusions, these results suggest that VWM resources appear to contribute to the occurrence of PoP, supporting the theory that PoP is, in fact, a multilevel process in which the deployment of spatial attention, relying on VWM representations, plays an important role.

Oh, the number of things you will process (in parallel)!

We highlight the importance of considering the variance produced during the parallel processing stage in vision and present a case for why it is useful to consider the "item" as a meaningful unit of study when investigating early visual processing in visual search tasks.