Individual differences predict low prevalence visual search performance

Reduced low-prevalence visual search detriment with increasing age: Implications for cognitive theories of aging and real-world search tasks

When performing multiple successive visual searches, low-prevalence targets are at elevated risk of being missed. This has important implications for real-world visual search tasks, such as diagnostic medical imaging (e.g., searching for a cancer) and airport baggage security screening (e.g., searching for a weapon), which are characterized by low-prevalence targets and potentially dire consequences of target misses. Previous work on low-prevalence visual search indicates that individuals who spontaneously respond more slowly miss fewer targets, which has been attributed to higher quitting thresholds predicting better performance. Previous aging research indicates that older adults typically respond more slowly across multiple task contexts. This has been attributed to both intrinsic limitations in processing speed and a strategic trade-off to prioritize accuracy with increasing age. Synthesizing these two separate lines of research, here we tested whether older adults had a higher quitting threshold and/or slower processing speed in low-prevalence visual search, and the consequences of these for the magnitude of the low-prevalence visual search detriment. We recruited a large sample (N = 380) across a range of ages (20-80 years) and had them search for targets under low- and high-prevalence conditions. Older adults had both slower processing speed and higher quitting thresholds. Older adults were moderately less susceptible to the low-prevalence detriment, and this relationship was mediated by countervailing effects: slower processing speed exacerbated older adults' low-prevalence detriment, whereas elevated quitting threshold mitigated it. Theoretical implications for cognitive aging and practical implications for professional visual search tasks are discussed.

AAPM WGPE report 394: Simulated error training for the physics plan and chart review

BACKGROUND

Simulated error training is a method to practice error detection in situations where the occurrence of error is low. Such is the case for the physics plan and chart review where a physicist may check several plans before encountering a significant problem. By simulating potentially hazardous errors, physicists can become familiar with how they manifest and learn from mistakes made during a simulated plan review.

PURPOSE

The purpose of this project was to develop a series of training datasets that allows medical physicists and trainees to practice plan and chart reviews in a way that is familiar and accessible, and to provide exposure to the various failure modes (FMs) encountered in clinical scenarios.

METHODS

A series of training datasets have been developed that include a variety of embedded errors based on the risk-assessment performed by American Association of Physicists in Medicine (AAPM) Task Group 275 for the physics plan and chart review. The training datasets comprise documentation, screen shots, and digital content derived from common treatment planning and radiation oncology information systems and are available via the Cloud-based platform ProKnow.

RESULTS

Overall, 20 datasets have been created incorporating various software systems (Mosaiq, ARIA, Eclipse, RayStation, Pinnacle) and delivery techniques. A total of 110 errors representing 50 different FMs were embedded with the 20 datasets. The project was piloted at the 2021 AAPM Annual Meeting in a workshop where participants had the opportunity to review cases and answer survey questions related to errors they detected and their perception of the project's efficacy. In general, attendees detected higher-priority FMs at a higher rate, though no correlation was found between detection rate and the detectability of the FMs. Familiarity with a given system appeared to play a role in detecting errors, specifically when related to missing information at different locations within a given software system. Overall, 96% of respondents either agreed or strongly agreed that the ProKnow portal and training datasets were effective as a training tool, and 75% of respondents agreed or strongly agreed that they planned to use the tool at their local institution.

CONCLUSIONS

The datasets and digital platform provide a standardized and accessible tool for training, performance assessment, and continuing education regarding the physics plan and chart review. Work is ongoing to expand the project to include more modalities, radiation oncology treatment planning and information systems, and FMs based on emerging techniques such as auto-contouring and auto-planning.

An investigation of cardiac vagal tone over time and its relation to vigilance performance: a growth curve modeling approach

Introduction

Research over the last couple of decades has demonstrated a relationship between psychophysiological measures, specifically cardiac functions, and cognitive performance. Regulation of the cardiac system under parasympathetic control is commonly referred to as cardiac vagal tone and is associated with the regulation of cognitive and socioemotional states. The goal of the current study was to capture the dynamic relationship between cardiac vagal tone and performance in a vigilance task.

Method/Results

We implemented a longitudinal growth curve modeling approach which unveiled a relationship between cardiac vagal tone and vigilance that was non-monotonic and dependent upon each person.

Discussion

The findings suggest that cardiac vagal tone may be a process-based physiological measure that further explains how the vigilance decrement manifests over time and differs across individuals. This contributes to our understanding of vigilance by modeling individual differences in cardiac vagal tone changes that occur over the course of the vigilance task.

Emphasizing responder speed or accuracy modulates but does not abolish the distractor-induced quitting effect in visual search

When a highly salient distractor is present in a search array, it speeds target absent visual search and increases errors during target present visual search, suggesting lowered quitting thresholds (Moher in Psychol Sci 31(1):31-42, 2020). Missing a critical target in the presence of a highly salient distractor can have dire consequences in real-world search tasks where accurate target detection is crucial, such as baggage screening. As such, the current study examined whether emphasizing either accuracy or speed would eliminate the distractor-generated quitting threshold effect (QTE). Three blocks of a target detection search task which included a highly salient distractor on half of all trials were used. In one block, participants received no instructions or feedback regarding performance. In the remaining two blocks, they received instructions and trial-by-trial feedback that either emphasized response speed or response accuracy. Overall, the distractor lowered quitting thresholds, regardless of whether response speed or response accuracy was emphasized in a block of trials. However, the effect of the distractor on target misses was smaller when accuracy was emphasized. It, therefore, appears that while the distractor QTE is not easily eradicated by explicit instructions and feedback, it can be shifted. As such, future research should examine the applicability of these and similar strategies in real-world search scenarios.

Delayed onsets are not necessary for generating distractor quitting thresholds effects in visual search

Salient distractors lower quitting thresholds in visual search. That is, when searching for the presence of a target among filler items, a large heterogeneously coloured distractor presented at a delayed onset produces quick target-absent judgements and increased target-present errors. The aim of the current study was to explore if the timing of the salient distractor modulates this Quitting Threshold Effect (QTE). In Experiment 1, participants completed a target detection search task in the presence or absence of a salient singleton distractor that either appeared simultaneously with other search items or appeared at a delayed onset (i.e., 100 ms or 250 ms after other array items appeared). In Experiment 2, a similar method was used, except that the salient singleton distractor appeared simultaneously, 100 ms before, or 100 ms after the other array items. Across both experiments, we observed robust distractor QTEs. Regardless of their onset, salient distractors decreased target-absent search speeds and increased target-present error rates. In all, the present findings suggest that delayed onsets are not required for lowered quitting thresholds in visual search.

Working Memory Capacity Depends on Attention Control, but Not Selective Attention

Working memory and attention are interrelated constructs that are sometimes even considered indistinguishable. Since attention is not a uniform construct, it is possible that different types of attention affect working memory capacity differently. To clarify this issue, we investigated the relationship between working memory capacity and various components of attention. The sample consisted of 136 healthy adult participants aged 18 to 37 years (M = 20.58, SD = 2.74). Participants performed tasks typically used to assess working memory (operation span, change detection, simple digit span, and adaptive digit span tasks), selective attention (visual search task), and attention control (Stroop and antisaccade tasks). We tested several models with working memory and attention, either as a unitary factor or being divided into selective attention and attention control factors. A confirmatory factor analysis showed that the model with three latent variables-working memory capacity, attention control, and selective attention-fit the data best. Results showed that working memory and attention are distinct but correlated constructs: working memory capacity was only related to attention control, whereas attention control was related to both constructs. We propose that differences in working memory capacity are determined only by the ability to maintain attention on the task, while differences in the ability to filter out non-salient distractors are not related to working memory capacity.

Interactive influences of emotion and extraversion on visual attention

INTRODUCTION

Emotion has been shown to influence selective visual attention. However, studies in this field have revealed contradictory findings regarding the nature of this influence. One possible explanation for the variation in findings is that affective inter-individual differences impact both attention and emotion and may therefore moderate any influence of emotion on attention. The current work is a novel investigation of the effects of induced emotional states and the traits of extraversion and neuroticism on visual attention. This allowed a direct investigation of any impact of extraversion and neuroticism on the way in which emotion influences attention.

METHODS

Participants were induced into positive, neutral, and negative emotional states before completing a change detection flicker task in which they were required to locate a change to a real-world scene as quickly and accurately as possible.

RESULTS

Participants scoring higher in extraversion were more accurate but slower at detecting changes. Importantly, this was particularly evident when induced into a negative emotional state compared to a neutral emotional state. Neuroticism had no impact on attention.

CONCLUSIONS

The current study provides evidence that extraversion can moderate the influence of negative emotion upon visual attention and may help to explain some of the contradictory findings in this research area. When considered independently, increased trait levels of extraversion were associated with improved change detection. Individuals higher in extraversion appear better equipped to regulate negative emotion compared to individuals lower in extraversion, supporting research linking extraversion to affective reactivity and models of psychopathology.

Perceptual Load and Sex-Specific Personality Traits

The impact of sex-specific personality traits has often been investigated for visuospatial tasks such as mental rotation, but less is known about the influence of personality traits on visual search. We investigated whether the Big Five personality traits Extroversion (E), Openness (O), Agreeableness (A), Conscientiousness (C), and Neuroticism (N) and the Autism Quotient (AQ) influence visual search in a sample of N = 65 men and women. In three experiments, we varied stimulus complexity and predictability. As expected, latencies were longer when the target was absent. Pop-out search was faster than conjunction search. A large number of distracters slowed down reaction times (RTs). When stimulus complexity was not predictable in Experiment 3, this reduced search accuracy by about half. As could be predicted based on previous research on long RT tails, conjunction search in target absent trials revealed the impact of personality traits. The RT effect in visual search of the accelerating "less social" AQ score was specific to men, while the effects of the "more social" decelerating Big Five Inventory factors agreeableness and conscientiousness were specific to women. Thus, sex-specific personality traits could explain decision-making thresholds, while visual stimulus complexity yielded an impact of the classic personality traits neuroticism and extroversion.

Exaggerated prevalence effect with the explicit prevalence information: The description-experience gap in visual search

Despite the increasing focus on target prevalence in visual search research, few papers have thoroughly examined the effect of how target prevalence is communicated. Findings in the judgment and decision-making literature have demonstrated that people behave differently depending on whether probabilistic information is made explicit or learned through experience, hence there is potential for a similar difference when communicating prevalence in visual search. Our current research examined how visual search changes depending on whether the target prevalence information was explicitly given to observers or they learned the prevalence through experience with additional manipulations of target reward and salience. We found that when the target prevalence was low, learning prevalence from experience resulted in more target-present responses and longer search times before quitting compared to when observers were explicitly informed of the target probability. The discrepancy narrowed with increased prevalence and reversed in the high target prevalence condition. Eye-tracking results indicated that search with experience consistently resulted in longer fixation durations, with the largest difference in low-prevalence conditions. Longer search time was primarily due to observers re-visited more items. Our work addressed the importance of exploring influences brought by probability communication in future prevalence visual search studies.

Face search in CCTV surveillance

Background

We present a series of experiments on visual search in a highly complex environment, security closed-circuit television (CCTV). Using real surveillance footage from a large city transport hub, we ask viewers to search for target individuals. Search targets are presented in a number of ways, using naturally occurring images including their passports and photo ID, social media and custody images/videos. Our aim is to establish general principles for search efficiency within this realistic context.

Results

Across four studies we find that providing multiple photos of the search target consistently improves performance. Three different photos of the target, taken at different times, give substantial performance improvements by comparison to a single target. By contrast, providing targets in moving videos or with biographical context does not lead to improvements in search accuracy.

Conclusions

We discuss the multiple-image advantage in relation to a growing understanding of the importance of within-person variability in face recognition.

Electronic supplementary material

The online version of this article (10.1186/s41235-019-0193-0) contains supplementary material, which is available to authorized users.

Using Eye Movements to Understand how Security Screeners Search for Threats in X-Ray Baggage

There has been an increasing drive to understand failures in searches for weapons and explosives in X-ray baggage screening. Tracking eye movements during the search has produced new insights into the guidance of attention during the search, and the identification of targets once they are fixated. Here, we review the eye-movement literature that has emerged on this front over the last fifteen years, including a discussion of the problems that real-world searchers face when trying to detect targets that could do serious harm to people and infrastructure.

Eye movement feedback fails to improve visual search performance

Many real-world searches (e.g., radiology and baggage screening) have rare targets. When targets are rare, observers perform rapid, incomplete searches, leading to higher miss rates. To improve search for rare (10% prevalence) targets, we provided eye movement feedback (EMF) to observers during their searches. Although the nature of the EMF varied across experiments, each method informed observers about the regions of the display that had not yet been inspected. We hypothesized that feedback would help guide attention to unsearched areas and increase the proportion of the display searched before making a target-absent response, thereby increasing accuracy. An eye tracker was used to mark fixated areas by either removing a semiopaque gray overlay (Experiments 1 and 4) as portions of the display were fixated or by adding the overlay once the eye left a segment of the image (Experiments 2 and 4). Experiment 3 provided automated EMF, such that a new region was uncovered every 540 milliseconds. Across experiments, we varied whether people searched for “Waldo” in images from “Where’s Waldo?” search books or searched for a T among offset Ls. We found weak evidence that EMF improves accuracy in Experiment 1. However, in the remaining experiments, EMF had no effect (Experiment 4), or even reduced accuracy (Experiments 2 and 3). We conclude that the one positive result we found is likely a Type I error and that the EMF method that we used is unlikely to improve visual search performance.