Specifying the precision of guiding features for visual search

Isolating the impact of a visual search template's color and form information on search guidance and verification times

Visual search can be guided by biasing one's attention towards features associated with a target. Prior work has shown that high-fidelity, picture-based cues are more beneficial to search than text-based cues. However, typically picture cues provide both detailed form information and color information that is absent from text-based cues. Given that visual resolution deteriorates with eccentricity, it is not clear that high-fidelity form information would benefit guidance to peripheral objects - much of the picture benefit could be due to color information alone. To address this, we conducted a search task with eye-tracking that had four types of cues that comprised a 2 (text/pictorial cue) × 2 (no color/color) design. We hypothesized that color information would be important for efficient search guidance while high-fidelity form information would be important for efficient verification times. In Experiment 1 cues were a colored picture of the target, a gray-scaled picture of the target, a text-based cue that included color (e.g., "blue shoe"), or a text-based cue without color (e.g., "shoe"). Experiment 2 was a replication of Experiment 1, except that the color word in the text-based cue was presented in the precise color that was the dominant color in the target. Our results show that high-fidelity form information is important for efficient verifications times (with color playing less of a role) and color is important for efficient guidance, but form information also benefits guidance. These results suggest that different features of the cue independently contribute to different aspects of the search process.

Task-adaptive changes to the target template in response to distractor context: Separability versus similarity

Theories of attention hypothesize the existence of an attentional template that contains target features in working or long-term memory. It is frequently assumed that the template contains a veridical copy of the target, but recent studies suggest that this is not true when the distractors are linearly separable from the target. In such cases, target representations shift "off-veridical" in response to the distractor context, presumably because doing so is adaptive and increases the representational distinctiveness of targets from distractors. However, some have argued that the shifts may be entirely explained by perceptual biases created by simultaneous color contrast. Here we address this debate and test the more general hypothesis that the target template is adaptively shaped by elements of the distractor context needed to distinguish targets from distractors. We used a two-dimensional target and separately manipulated the linear separability of one dimension (color) and the visual similarity of the other (orientation). We found that target shifting along the linearly separable color dimension was dependent on the similarity of targets-to-distractors along the other dimension. The target representations were consistent with a postexperiment strategy questionnaire in which participants reported using color more when orientation was hard to use, and orientation more when it was easier to use. We conclude that the target template is task-adaptive and exploit features in the distractor context that most predictably distinguish targets from distractors to increase visual search efficiency. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Good-enough attentional guidance

Theories of attention posit that attentional guidance operates on information held in a target template within memory. The template is often thought to contain veridical target features, akin to a photograph, and to guide attention to objects that match the exact target features. However, recent evidence suggests that attentional guidance is highly flexible and often guided by non-veridical features, a subset of features, or only associated features. We integrate these findings and propose that attentional guidance maximizes search efficiency based on a 'good-enough' principle to rapidly localize candidate target objects. Candidates are then serially interrogated to make target-match decisions using more precise information. We suggest that good-enough guidance optimizes the speed-accuracy-effort trade-offs inherent in each stage of visual search.

Mandating Limits on Workload, Duty, and Speed in Radiology

Research has not yet quantified the effects of workload or duty hours on the accuracy of radiologists. With the exception of a brief reduction in imaging studies during the 2020 peak of the COVID-19 pandemic, the workload of radiologists in the United States has seen relentless growth in recent years. One concern is that this increased demand could lead to reduced accuracy. Behavioral studies in species ranging from insects to humans have shown that decision speed is inversely correlated to decision accuracy. A potential solution is to institute workload and duty limits to optimize radiologist performance and patient safety. The concern, however, is that any prescribed mandated limits would be arbitrary and thus no more advantageous than allowing radiologists to self-regulate. Specific studies have been proposed to determine whether limits reduce error, and if so, to provide a principled basis for such limits. This could determine the precise susceptibility of individual radiologists to medical error as a function of speed during image viewing, the maximum number of studies that could be read during a work shift, and the appropriate shift duration as a function of time of day. Before principled recommendations for restrictions are made, however, it is important to understand how radiologists function both optimally and at the margins of adequate performance. This study examines the relationship between interpretation speed and error rates in radiology, the potential influence of artificial intelligence on reading speed and error rates, and the possible outcomes of imposed limits on both caseload and duty hours. This review concludes that the scientific evidence needed to make meaningful rules is lacking and notes that regulating workloads without scientific principles can be more harmful than not regulating at all.

From "satisfaction of search" to "subsequent search misses": a review of multiple-target search errors across radiology and cognitive science

For over 50 years, the satisfaction of search effect has been studied within the field of radiology. Defined as a decrease in detection rates for a subsequent target when an initial target is found within the image, these multiple target errors are known to underlie errors of omission (e.g., a radiologist is more likely to miss an abnormality if another abnormality is identified). More recently, they have also been found to underlie lab-based search errors in cognitive science experiments (e.g., an observer is more likely to miss a target 'T' if a different target 'T' was detected). This phenomenon was renamed the subsequent search miss (SSM) effect in cognitive science. Here we review the SSM literature in both radiology and cognitive science and discuss: (1) the current SSM theories (i.e., satisfaction, perceptual set, and resource depletion theories), (2) the eye movement errors that underlie the SSM effect, (3) the existing efforts tested to alleviate SSM errors, and (4) the evolution of methodologies and analyses used when calculating the SSM effect. Finally, we present the attentional template theory, a novel mechanistic explanation for SSM errors, which ties together our current understanding of SSM errors and the attentional template literature.

Search for the Unknown: Guidance of Visual Search in the Absence of an Active Template

Can you efficiently look for something even without knowing what it looks like? According to theories of visual search, the answer is no: A template of the search target must be maintained in an active state to guide search for potential locations of the target. Here, we tested the need for an active template by assessing a case in which this template is improbable: the search for a familiar face among unfamiliar ones when the identity of the target face is unknown. Because people are familiar with hundreds of faces, an active guiding template seems unlikely in this case. Nevertheless, participants (35 Israelis and 33 Germans) were able to guide their search as long as extrafoveal processing of the target features was possible. These results challenge current theories of visual search by showing that guidance can rely on long-term memory and extrafoveal processing rather than on an active search template.

Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy

Errors in radiologic interpretation are largely the result of failures of perception. This remains true despite the increasing use of computer-aided detection and diagnosis. We surveyed the literature on visual illusions during the viewing of radiologic images. Misperception of anatomical structures is a potential cause of error that can lead to patient harm if disease is seen when none is present. However, visual illusions can also help enhance the ability of radiologists to detect and characterize abnormalities. Indeed, radiologists have learned to exploit certain perceptual biases in diagnostic findings and as training tools. We propose that further detailed study of radiologic illusions would help clarify the mechanisms underlying radiologic performance and provide additional heuristics to improve radiologist training and reduce medical error.

Categorical cuing: Object categories structure the acquisition of statistical regularities to guide visual search

Recent statistical regularities have been demonstrated to influence visual search across a wide variety of learning mechanisms and search features. To function in the guidance of real-world search, however, such learning must be contingent on the context in which the search occurs and the object that is the target of search. The former has been studied extensively under the rubric of contextual cuing. Here, we examined, for the first time, categorical cuing: The role of object categories in structuring the acquisition of statistical regularities used to guide visual search. After an exposure session in which participants viewed six exemplars with the same general color in each of 40 different real-world categories, they completed a categorical search task, in which they searched for any member of a category based on a label cue. Targets that matched recent within-category regularities were found faster than targets that did not (Experiment 1). Such categorical cuing was also found to span multiple recent colors within a category (Experiment 2). It was observed to influence both the guidance of search to the target object (Experiment 3) and the basic operation of assigning single exemplars to categories (Experiment 4). Finally, the rapid acquisition of category-specific regularities was also quickly modified, with the benefit rapidly decreasing during the search session as participants were exposed equally to the two possible colors in each category. The results demonstrate that object categories organize the acquisition of perceptual regularities and that this learning exerts strong control over the instantiation of the category representation as a template for visual search. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Selective attention to stimulus representations in perception and memory: commonalities and differences

It has been proposed that the deployment of selective attention to perceptual and memory representations might be governed by similar cognitive processes and neural resources. However, evidence for this simple and appealing proposal remains inconclusive, which might be due to a considerable divergence in tasks and cognitive demands when comparing attentional selection in memory versus perception. To examine whether selection in both domains share common attentional processes and only differ in the stimuli they act upon (external vs. internal), we compared behavioral costs or benefits between selection domains. In both domains, participants had to attend a target stimulus from a set of simultaneously presented stimuli or simultaneously active memory representations, respectively, with set, target, or both, being repeated or changed across trials. The results of two experiments delineated principal similarities and differences of selection processes in both domains: While positive priming from stimulus repetition was found in both selection domains, we found no consistent effects of negative priming when shifting the focus of attention to a previously to-be-ignored stimulus. However, priming in the perception task was mainly due to repetitions of the target feature (here: color), whereas for the memory task, repetition of the same set of stimulus representations was most important. We propose that the differences can be attributed to a reduced cognitive effort when the now relevant memory representation had already been pre-activated (even as a distractor) in the previous trial. Additionally, our experiments both underscore the importance of taking stimulus-response associations into account, which may be a hidden factor behind differences between domains. We conclude that any attempt of comparing internal versus external attentional selection has to consider inherent differences in selection dynamics across representational domains.

What do radiologists look for? Advances and limitations of perceptual learning in radiologic search

Supported by guidance from training during residency programs, radiologists learn clinically relevant visual features by viewing thousands of medical images. Yet the precise visual features that expert radiologists use in their clinical practice remain unknown. Identifying such features would allow the development of perceptual learning training methods targeted to the optimization of radiology training and the reduction of medical error. Here we review attempts to bridge current gaps in understanding with a focus on computational saliency models that characterize and predict gaze behavior in radiologists. There have been great strides toward the accurate prediction of relevant medical information within images, thereby facilitating the development of novel computer-aided detection and diagnostic tools. In some cases, computational models have achieved equivalent sensitivity to that of radiologists, suggesting that we may be close to identifying the underlying visual representations that radiologists use. However, because the relevant bottom-up features vary across task context and imaging modalities, it will also be necessary to identify relevant top-down factors before perceptual expertise in radiology can be fully understood. Progress along these dimensions will improve the tools available for educating new generations of radiologists, and aid in the detection of medically relevant information, ultimately improving patient health.

Examining the influence of different types of dynamic change in a visual search task

It has been repeatedly demonstrated that when performing a visual search task, items can pop out of a display such that they are identified rapidly, independent of the number of distractors present. It has been less clear whether this type of pop-out is limited to static displays (e.g., images) or whether it can also occur in scenes containing movement, more akin to how we experience the real world. Recently, Jardine and Moore (Journal of Experimental Psychology: Human Perception and Performance, 42, 617-630, 2016) examined whether pop-out also occurs in displays consisting of dynamic motion - wherein items in the display rotated continuously until a critical frame that would elicit pop-out under static presentation conditions - and found that search was greatly impaired. It remains unclear, however, whether such impairment is exerted equivalently across all types of dynamic motions or if it is specific to orientation. In the present study, we replicate the original Jardine and Moore (Journal of Experimental Psychology: Human Perception and Performance, 42, 617-630, 2016) finding and extend this examination to another dimension - color change. We also explore whether search efficiency can be improved with dynamic context if aspects of the display become predictable. The results suggest that not all types of dynamic change impair search performance. Specifically, oddball color targets continue to pop out even when the items in the display are dynamic. Interestingly, adding predictable context did not aid search accuracy as expected, rather resulting in poorer performance. Taken together, the findings suggest that the influence of dynamic context on search performance is not absolute.