The effects of visual lobe training with easy and difficult targets on changes of visual lobe shape characteristics and visual search performance

This study aimed to study the effects of training on visual lobe shape characteristics with two levels of target difficulty (an easy target O and a difficult target V) and to study the transfer effect from lobe shape training to visual search performance. It was found that there was a noticeable improvement in lobe area and roundness for the difficult target lobes with the difficult target training groups, and that lobe area and roundness showed greatest sensitivity to the effects of training. The easy target lobes for the difficult target training group did not show any differences between pretest and posttest. There was a narrowing of differences in shape parameters between the two target difficulties from pretest to posttest after lobe mapping practice, suggesting that such practice could minimize lobe shape differences for different job difficulties. Search task practice was found to improve search performance, but lobe training produced no additional benefit for search time. Correlation analysis between lobe shape parameters and search time showed that a significant relationship existed only for the long time search task, indicating that mathematical models previously developed for search performance prediction may not be valid for short time search tasks.

Relevance to industry

This research showed the relative sensitivity of different lobe shape indexes from training and indicated the importance of selecting an appropriate level of target difficulty for enhancing training effectiveness.     

Effects of speed,motion type,and stimulus size on dynamic visual search: A study of radar human–machine interface

Human visual perception behavior in dynamic environments could be affected by the motion properties of stimuli. The purpose of this study was to investigate the effects of motion type, size, and speed of stimulus on visual search performance and visual comfort in both single- and double-target tasks. Twenty participants attended an experiment in which they finished two tasks at three speeds (low, medium, and high), in two motion types (flicker, uniform), with varied levels of stimulus size (small, medium, and large) on a display. The search time, accuracy, critical flicker frequency, visual comfort, and cognitive load were recorded to provide a comprehensive understanding of participants' visual preferences during the experiment.The results indicated the increasing speed would weaken participants performance on visual search tasks; Medium-sized stimuli were recommended considering search efficiency and cost-effectiveness; More importantly, the present study also found that flicker motion led to better task performance in the low-speed task, due to increased alertness and lead physiological arousal effects, which may imply the past studies have overstated the negative effects of flickering in dynamic environments.     

A blessing,not a curse: Experimental evidence for beneficial effects of visual aesthetics on performance

The present experiment investigated the effect of visual aesthetics on performance. A total of 257 volunteers completed a series of search tasks on a website providing health-related information. Four versions of the website were created by manipulating visual aesthetics (high vs. low) and usability (good vs. poor) in a 2 × 2 between-subjects design. Task completion times and error rates were used as performance measures. A main effect of usability on both error rates and completion time was observed. Additionally, a significant interaction of visual aesthetics and usability revealed that high aesthetics enhanced performance under conditions of poor usability. Thus, in contrast to the notion that visual aesthetics may worsen performance, visual aesthetics even compensated for poor usability by speeding up task completion. The practical and theoretical implications of this finding are discussed.     

Evaluation of a job‐aiding tool in inspection systems

Visual inspection plays a very important role in ensuring quality in the manufacturing and service industries. Two determinants of inspection performance are visual search and decision‐making. Improvement in any one of the components will have an impact on system performance. Job‐aids, accompanied by training, have proven to be effective in enhancing accuracy and reducing search time in visual inspection systems. This article aims to investigate the effects of search strategy along with task complexity and pacing on inspection performance using a job‐aiding tool. To facilitate the experiments, an enhanced job‐aiding tool in a simulated visual inspection environment was developed. This tool enables an inspector to track his or her search path in visual inspection systems. A pilot study and two experiments were conducted using this tool. The pilot study examined the effectiveness of the job‐aiding tool. The first experiment studied the effect of search strategy and task complexity on inspection system performance and the second experiment studied the impact of search strategy, task complexity, and pacing on system performance. Results from this research can be used to better design an inspection system. © 2007 Wiley Periodicals, Inc.     

Biases on visual warnings during multiple target visual searches on mine monitoring interface

With the continuous development of human–computer interaction, some industrial monitoring systems have gradually evolved from a single monitoring device to a comprehensive monitoring system platform, and multi-objective visual search is particularly important in the field of industrial monitoring. This study investigates the effect of conceptual and perceptual biases on similarity bias in multiple target visual searches and proposes relevant design strategies that can be applied to warning interfaces. The results of two experiments show that the effect of the similarity bias is due to the combined effects of conceptual and perceptual similarities, and on this basis, we propose a design strategy for the interface of a gas extraction monitoring system used in mines in a third experiment. An existing interface to monitor gas extraction and a proposed interface with modifications made to the existing interface are evaluated. The results confirm that the modified interface effectively improves visual search performance during multiple target visual searches. The research findings are important for reducing cognitive decision errors during related monitoring work and ensuring the performance of the mine gas safety monitoring system interfaces. The findings can also guide the designing of visual warning elements of different targets for other monitoring interfaces.     

Use of aiding and feedback in improving visual search performance for an inspection task

The objective of this research is to evaluate the effect of providing online feedback, process, and process plus performance on visual search performance for a printed circuit board inspection task. A training aid was developed that provided process and process plus performance feedback and enabled a comparison between the two feedback strategies. Two search strategies—search by area and search by component—were adopted to complete the task, and their sensitivity to the type of feedback and search performance was evaluated. Providing process plus performance feedback helped in improving speed and accuracy, whereas area search strategy proved beneficial in improving search speed for both feedback strategies. Graphical feedback on the component location helped in locating more component defects than area defects. © 2003 Wiley Periodicals, Inc. Hum Factors Man 13: 115–136, 2003.     

The use of expert knowledge in the development of simulations for train driver training

The current study was undertaken to inform the development of simulations for improving train driver’s decision making under degraded track conditions. Trains are sophisticated heavy machinery and their performance is ever increasing resulting in the driving task becoming more complex and progressively dominated by cognitive and perceptual skills. A critical part of reducing the potential for train driver error and of increasing performance lies in the appropriate design of simulation training. In the current study a cognitive task analysis, using the critical decision method (CDM) was undertaken using a focus group research design. The process resulted in increased knowledge of expert train driver decision-making processes. Across four major incidents analyzed 11 decision points, 17 cues, 30 essential responsive actions and 45 possible errors where identified. The use of these results for supporting the design of simulation training and associated performance measures is discussed.     

Effects of speed–accuracy instructions on oculomotor scanning and target recognition in a simulated baggage X-ray screening task

Visual search tasks are often carried out under high levels of time stress. Transportation security screeners, for example, face demands to achieve high levels of accuracy while maintaining rapid passenger throughput. An experiment examined the strategies by which operators regulate visual search performance under such conditions. Observers performed a simulated baggage-screening task under instructions to emphasise either response speed or accuracy. Behavioural measures and eye movements were recorded. Observers made fewer and briefer fixations under emphasise-speed than under emphasise-accuracy instructions. Losses in accuracy were produced by more frequent failures to fixate on targets and a decrease in the detection rate of non-fixated targets. The likelihood with which observers detected a fixated target was similar across speed–accuracy instructions. Results will inform efforts to model visual search in naturalistic tasks, allowing more accurate prediction of response times and error rate and may aid the design of training programmes and other interventions to improve search performance under stress.     

The perception of hazard I. Hazard analysis and the contribution of visual search to hazard perception

Rockfall accidents are an important determinant of safety performance in deep level mining. Previous research which is reviewed suggests that a lack of skill in perceiving warnings of imminent danger may be an important factor contributing to this kind of accident. The perceptual task of mine workers is described briefly and a survey of the visual characteristics of dangerous rock is reported upon. The visual search performance of mine workers in a stope simulator, designed on the basis of the survey results, was studied. The findings show not only that novice mine workers, when compared with experienced men, lack the ability to search adequately in a simulation of dangerous rock, but also that their search skills can be improved significantly by training.     

A multi-level approach of evaluating crew resource management training: a laboratory-based study examining communication skills as a function of team congruence

The article proposes a multi-level approach for evaluating communication skills training (CST) as an important element of crew resource management (CRM) training. Within this methodological framework, the present work examined the effectiveness of CST in matching or mismatching team compositions with regard to hierarchical status and competence. There is little experimental research that evaluated the effectiveness of CRM training at multiple levels (i.e. reaction, learning, behaviour) and in teams composed of members of different status and competence. An experiment with a two (CST: with vs. without) by two (competence/hierarchical status: congruent vs. incongruent) design was carried out. A total of 64 participants were trained for 2.5 h on a simulated process control environment, with the experimental group being given 45 min of training on receptiveness and influencing skills. Prior to the 1-h experimental session, participants were assigned to two-person teams. The results showed overall support for the use of such a multi-level approach of training evaluation. Stronger positive effects of CST were found for subjective measures than for objective performance measures.

Statement of Relevance: This work provides some guidance for the use of a multi-level evaluation of CRM training. It also emphasises the need to collect objective performance data for training evaluation in addition to subjective measures with a view to gain a more accurate picture of the benefits of such training approaches.     

Effectiveness of auditory and tactile crossmodal cues in a dual-task visual and auditory scenario

Abstract

In this study, we examined how spatially informative auditory and tactile cues affected participants’ performance on a visual search task while they simultaneously performed a secondary auditory task. Visual search task performance was assessed via reaction time and accuracy. Tactile and auditory cues provided the approximate location of the visual target within the search display. The inclusion of tactile and auditory cues improved performance in comparison to the no-cue baseline conditions. In comparison to the no-cue conditions, both tactile and auditory cues resulted in faster response times in the visual search only (single task) and visual–auditory (dual-task) conditions. However, the effectiveness of auditory and tactile cueing for visual task accuracy was shown to be dependent on task-type condition. Crossmodal cueing remains a viable strategy for improving task performance without increasing attentional load within a singular sensory modality.

Practitioner Summary: Crossmodal cueing with dual-task performance has not been widely explored, yet has practical applications. We examined the effects of auditory and tactile crossmodal cues on visual search performance, with and without a secondary auditory task. Tactile cues aided visual search accuracy when also engaged in a secondary auditory task, whereas auditory cues did not.     

How information within the perceptual span guides visual search and aids perception

We explore the guiding effect of task-related information appearing within the perceptual span on visual search based on elements such as the range of effective information attention within the perceptual span and the orientation of task-related objects. In the first experiment, we recorded reaction time and eye movement data of 48 subjects performing a visual search task for target information in the navigation interface and divided them into four experimental groups according to the perceptual span (within or outside the range) and orientation (left or right) of the task-related information. The experimental results showed that: (a) task-related information appearing within the perceptual span had a guiding effect on target search; and (b) the right side closer to the target in task search have better performance in guiding. In the second experiment, eye-movement experiments of the navigation interface based on the eye-movement processing theoretical model of linguistics showed that: (a) within the perceptual span, the shifting of attention causing eye movements (saccade) and brings gaze into the area of interest, and (b) the perceptual span moves with attention shifts. This study provides evidence for cognitive processing of information responses within the perceptual span and dynamic adjustment of perceptual span location and provides a reliable method for effective information presentation and visual layout in navigation interfaces, with a view to providing reference and learning for related studies.     

基于异构CMP的改进蚁群优化任务调度策略

为提高异构CMP任务调度执行效率,充分发挥异构CMP的异构性和并行能力,提出一种基于异构CMP的改进蚁群优化任务调度算法--IACOTS。IACOTS算法首先建立任务调度模型、路径选择规则和信息素更新规则,使蚁群算法能够适用于异构CMP任务调度问题。同时通过采用动态信息素更新、相遇并行搜索策略和引入遗传算法中的变异因子对基本的蚁群算法进行优化,克服蚁群算法搜索时间过长和“早熟”现象。通过仿真实验获得的结果表明,IACOTS算法执行效率优于现有的遗传算法,完成相同的任务需要的迭代次数最少,能有效降低程序执行时间,适用于异构CMP等大规模并行环境的任务调度。     

Use of job aid to promote systematic search under different levels of task complexity

Job aids of various kinds have improved visual‐inspection performance. In particular, these job aids include a dynamic pointer that traces a systematic scan path across a search field. The efficacy of this specific job aid, however, has only been verified under a limited set of conditions. Moreover, the effectiveness of this job aid is a function of the speed of the pointer. Thus, it remains to be determined what pointer speeds will yield the best performances under a wide range of conditions. These conditions are defined here by four of the following task‐complexity factors: background density, fault rate, target conspicuity, and fault mix; the performance measure used is search accuracy. In general, increasing either the speed of the cursor or task complexity degraded accuracy, and the optimal pointer speed was specific to the conditions. © 2002 Wiley Periodicals, Inc.     

Interactions of perceptual and conceptual processing: Expertise in medical image diagnosis

In this study, we selected medical image diagnosis as a task to investigate how expertise influences the relations between perceptual and conceptual processing. In an experiment, participants, namely five novices and five experts, made diagnoses on 13 CT images. We obtained two types of data concerning verbal protocols and manipulating computational systems. The segments related to perceptual and conceptual processing were extracted from these data, and the interrelations of the two components were analyzed. Consequently, we confirmed three salient features in the experts: (1) the experts verbalized more types of findings and more types of hypotheses than novices; (2) the experts generated several hypotheses in the early phases of the task; and (3) they newly verbalized many perceptual features during conceptual activities, and verbalized conceptual words during perceptual activities. These results suggest that expertise in medical image diagnosis involves not only the development of both perceptual and conceptual processing, but also the development of an ability to connect the two components.     

Influence of social presence on eye movements in visual search tasks

Abstract

This study employed an eye-tracking technique to investigate the influence of social presence on eye movements in visual search tasks. A total of 20 male subjects performed visual search tasks in a 2 (target presence: present vs. absent) × 2 (task complexity: complex vs. simple) × 2 (social presence: alone vs. a human audience) within-subject experiment. Results indicated that the presence of an audience could evoke a social facilitation effect on response time in visual search tasks. Compared with working alone, the participants made fewer and shorter fixations, larger saccades and shorter scan path in simple search tasks and more and longer fixations, smaller saccades and longer scan path in complex search tasks when working with an audience. The saccade velocity and pupil diameter in the audience-present condition were larger than those in the working-alone condition. No significant change in target fixation number was observed between two social presence conditions.

Practitioner Summary: This study employed an eye-tracking technique to examine the influence of social presence on eye movements in visual search tasks. Results clarified the variation mechanism and characteristics of oculomotor scanning induced by social presence in visual search.     

The neural dynamics for hysteresis in visual perception

The hysteresis in the perception has been observed in many perceptual experiments, but little is known about the underlying dynamical mechanism. We simulate a visual discrimination task, as an example of hysteresis in the perception, using a spiking neuron network and the corresponding slow dynamic system. The hysteresis in visual perception has been reproduced in our simulation. We find that hysteresis is influenced by the change speed of the external stimuli and the excitatory recurrent interaction inside the selective neuron pool. The slow dynamic system reveals the dynamical mechanism underlying the hysteresis: emerging from the lag between the response of neural system and the fast change external stimuli when the slow dynamic system has a single steady state; emerging from the multiple steady states regardless of the change speed of the external stimuli. In particularly, the multiplicity of the steady state of the slow dynamic system comes from the codimension three swallowtail catastrophe which exhibits two interacting cusp catastrophes.     

Integrating complex information with object displays: psychophysical evaluation of outlines

The interactive use of visual interface tools has diversified the use of visualisations. This article reviews the relevant aspects of interaction and challenges the sufficiency of traditional evaluation criteria developed for static graphs. Traditionally, the problem for statisticians has been to maintain perceptual discriminability of details, when quantities of data increase. Currently, however, even non-professional users need to integrate qualitatively different kinds of information. The review of task requirements indicates the use of a visual outline: (1) visual tools can facilitate parallel separation of individual data entities and integration of their features and (2) more focused comparisons require visual memory due to eye movements. The article reports psychophysical experiments that measure performance accuracy and response latency conditioned by the above task requirements. The impact of shape and colour on performance interacted with display times; the times were shorter (100 ms) or longer (1 s) than the duration of typical gaze fixation. The features of graphs in the experiments were derived from a popular internet service. Thus, we describe methods for evaluating visual components of real services and provide general guidelines for visual design of human–computer interaction.     

Gaze behavior of spotters during an air-to-ground search

OBJECTIVE: This study was designed to develop methods for evaluating the gaze behaviors of spotters during air-to-ground search and to compare field-derived measures with previous lab results. Secondary aims were to assess adherence to a prescribed scan path, evaluate search effectiveness, and determine the predictors of task success. BACKGROUND: Crashed aircraft must be located quickly to minimize loss of life, often requiring visual search from the air. METHOD: Eye movements were measured in 10 volunteer spotters while they searched from the air for ground targets. Visual acuity, contrast levels, and performance on a lab-based search task were also measured. RESULTS: Results were similar to those of previous lab-based studies of air-to-ground search. Task success could be predicted best from a combination of gaze and laboratory variables, and as in previous research, experience was not one of them. CONCLUSIONS: In both lab and field research, performance is poor. Improvements in air search and rescue success will depend upon improvements in training, the refinement of scan tactics, changes to the task methods or environment, or modifications to parameters of the search exercise. APPLICATION: Spotters were unable to reliably search their assigned area, which has implications for the current search training program and in-the-air protocol.     

Micro-crack inspection in heterogeneously textured solar wafers using anisotropic diffusion

This paper proposes a machine vision scheme for detecting micro-crack defects in solar wafer manufacturing. The surface of a polycrystalline silicon wafer shows heterogeneous textures, and the shape of a micro-crack is similar to the multi-grain background. They make the automated visual inspection task extremely difficult.