An eye-tracking study examining information search in transit maps. Using China’s high-speed railway map as a case study

This study investigates the legibility of China’s high-speed railway map through eye-tracking measurement. The information searching process was identified by conducting: (1) Scoping stage – a user performance test and interview to inform the design of the eye-tracking study; (2) In-depth stage – an eye-tracking study. A number of visual design problems with the map have been identified. This research explores user-centered design map solutions and provides detailed design guidance for transit maps. It also demonstrates that eye-tracking is an effective method of evaluating the design quality of a transit map as it can identify design limitations and user needs

Using Eye Movement Data Visualization to Enhance Training of Air Traffic Controllers: A Dynamic Network Approach

The Federal Aviation Administration (FAA) forecasted substantial increase in the US air traffic volume creating a high demand in Air Traffic Control Specialists (ATCSs). Training times and passing rates for ATCSs might be improved if expert ATCSs’ eye movement (EM) characteristics can be utilized to support effective training. However, effective EM visualization is difficult for a dynamic task (e.g. aircraft conflict detection and mitigation) that includes interrogating multi-element targets that are dynamically moving, appearing, disappearing, and overlapping within a display. To address the issues, a dynamic network-based approach is introduced that integrates adapted visualizations (i.e. time-frame networks and normalized dot/bar plots) with measures used in network science (i.e. indegree, closeness, and betweenness) to provide in-depth EM analysis. The proposed approach was applied in an aircraft conflict task using a high-fidelity simulator; employing the use of veteran ATCSs and pseudo pilots. Results show that, ATCSs’ visual attention to multi-element dynamic targets can be effectively interpreted and supported through multiple evidences obtained from the various visualization and associated measures. In addition, we discovered that fewer eye fixation numbers or shorter eye fixation durations on a target may not necessarily indicate the target is less important when analyzing the flow of visual attention within a network. The results show promise in cohesively analyzing and visualizing various eye movement characteristics to better support training. 

Designs and Algorithms to Map Eye Tracking Data with Dynamic Multielement Moving Objects

Design concepts and algorithms were developed to address the eye tracking analysis issues that arise when (1) participants interrogate dynamic multielement objects that can overlap on the display and (2) visual angle error of the eye trackers is incapable of providing exact eye fixation coordinates. These issues were addressed by (1) developing dynamic areas of interests (AOIs) in the form of either convex or rectangular shapes to represent the moving and shape-changing multielement objects, (2) introducing the concept of AOI gap tolerance (AGT) that controls the size of the AOIs to address the overlapping and visual angle error issues, and (3) finding a near optimal AGT value. The approach was tested in the context of air traffic control (ATC) operations where air traffic controller specialists (ATCSs) interrogated multiple moving aircraft on a radar display to detect and control the aircraft for the purpose of maintaining safe and expeditious air transportation. In addition, we show how eye tracking analysis results can differ based on how we define dynamic AOIs to determine eye fixations on moving objects. The results serve as a framework to more accurately analyze eye tracking data and to better support the analysis of human performance

Development of methodologies to analyze and visualize air traffic controllers’ visual scanning strategies

The Federal Aviation Administration (FAA) estimates a 60 million air traffic volume by 2040. However, the available workforce of expert air traffic controllers (ATCs) might not be sufficient to manage this anticipated high traffic volume. Thus, to maintain the same safety standard and service level for air travel, more ATCs will need to be trained quickly. Previous research shows eye tracking technology can be used to enhance the training of the ATC’s by reducing their false alarm rate, thereby helping to mitigate the impact of increasing demand. Methods need to be developed to better understand experts’ eye movement (EM) data so as to incorporate them effectively in ATCs’ training process. However, it’s challenging to analyze ATCs’ EM data for several factors: (i) aircraft representation on radar display (i.e. targets) are dynamic, as their shape and position changes with time; (ii) raw EM data is very complex to visualize, even for the meaningful small duration (e.g. task completion time of 1 min); (iii) in the absence of any predefined order of visual scanning, each ATC employ a variety of scanning strategies to manage traffic, making it challenging to extract relevant patterns that can be taught. To address these aforementioned issues, a threefold framework was developed: (i) a dynamic network-based approach that can map expert ATCs’ EM data to dynamic targets, enabling the representation of visual scanning strategy evolution with time; (ii) a novel density-based clustering method to reduce the inherent complexity of ATCs’ raw EM data to enhance its visualization; (iii) a new modified n-gram based similarity analysis method, to evaluate the consistency and similarity of visual scanning strategies among experts. Two different experiments were conducted at the FAA Civil Aerospace Medical Institute in Oklahoma City, where EM data of 15 veteran ATCs’ (> 20 years of experience) were collected using eye trackers (Facelab and Tobii eye trackers), while they were controlling a high-fidelity simulated air traffic. The first experiment involved en-route traffic scenario (with aircraft above 18,000 feet) and the second experiment consisted of airport tower traffic (aircraft within 30 miles radius from an airport). The dynamic network analysis showed three important results: (i) it can be used to effectively represent which are the important targets and how their significance evolves over time, (ii) in dynamic scenarios, having targets having variable time on display, traditional target importance measure (i.e. the number of eye fixations and duration) can be misleading, and (iii) importance measures derived from the network-based approach (e.g. closeness, betweenness) can be used to understand how ATCs’ visual attention moves between targets. The result from the density-based clustering method shows that by controlling its two parameter values(i.e. spatial and temporal approximation), the visualization of the raw EM data can be substantially simplified. This approximate representation can be used for better training purpose where expert ATC’s visual scanning strategy can be visualized with reduced complexity, thereby enhancing the understanding of novices while maintaining its significant pattern (key for visual pattern mining). Moreover, the model parameters enable the decision-maker to incorporate context-dependent factors by adjusting the spatial (in pixel) and temporal (in milliseconds) thresholds used for the visual scanning approximation. The modified n-gram approach allows for twofold similarity analysis of EM data: (i) detecting similar EM patterns due to exact sequential match in which the targets are focused and/or grouped together visually because of several eye fixation transitions among them, and (ii) unearth similar visual scanning behavior which is otherwise small perturbed version of each other that arise as a result of idiosyncrasies of ATCs. Thus, this method is more robust compared to other prevalent approaches which employ strict definitions for similarity that are difficult to empirically observe in real-life scenarios. To summarize, the three methods developed allow us to apply a comprehensible framework to understand the evolving nature of the visual scanning strategy in complex environments (e.g. air traffic control task) by: (i) by identifying target importance & their evolution; (ii) simplifying visualizing of complex EM strategy for easier comprehension; (iii) evaluating similarity among various visual scanning strategies in dynamic scenarios

The effect of manipulating action observation variables on corticospinal excitability using transcranial magnetic stimulation

Action observation interventions have been shown to contribute to improvements in motor performance and (re)learning. This thesis examined the effect of manipulating action observation variables on corticospinal excitability (CSE) using transcranial magnetic stimulation (TMS), with the aim of informing interventions for motor (re)learning. Eye-tracking and interview techniques were employed in combination with TMS to provide novel explorations for how screen position, visual context, and emotional valence influence CSE, visual attention, and individual experience during action observation. The Pilot Experiment (Chapter 5) tested the appropriateness of both single- and paired-pulse TMS techniques during action observation. Results determined that single-pulse TMS was appropriate for the subsequent experiments included in this thesis. Experiment 1 (Chapter 6) investigated the effect of screen position during action observation on CSE. The results demonstrated greater CSE during action observation on a horizontal, compared to a vertical, screen position, but only once each individual’s viewing preference had been taken into account. Experiment 2 (Chapter 7) investigated the effect of congruent and incongruent contexts on CSE. The results indicated that congruent context during action observation facilitates CSE more than control conditions in contrast to an incongruent visual context. Experiment 3 (Chapter 8) explored the effect of each participant’s most preferred, least preferred, and neutral preference food items involved in an observed reach and grasp action on CSE. The results showed no significant differences between the control condition and observing a reach and grasp of each participant’s personalised least preferred and neutral preference food items. Significant inhibition of CSE was shown during observation of a reach and grasp of each participant’s most preferred food item. The three main experiments in this thesis provide novel contributions to action observation literature by incorporating eye-tracking and interview techniques in combination with TMS to better determine the nature of CSE modulation. Taken together, these findings directly inform both future research and practice in motor (re)learning by highlighting the importance of meaning and context during action observation

Visual communications of transportation system: Using information design to strengthen the legibility of transit maps

This thesis developed design solutions to enhance the legibility of transit maps by using information design knowledge. The author followed a user-centred approach to observe participants' reading behaviour and provide design solutions that meet user needs and expectations. In this study, the transit map is re-defined as an information design material rather than a cartographic map or a computerised diagram. The transit map design is divided into three main topics: information communication, visual design, and user performance. China's high-speed railway map is used as a case study where user performance tests are conducted to ascertain whether re-designing the map according to information design principles improves the map's legibility and makes it more user-friendly. The main focus is on information communication effectiveness, including map legend and instructional systems on the map; and on the visual design elements, including colour system, transit line layout, transfer signs and typography, etc. Finally, design guidance is established for transit maps based on the literature review and on the research findings of this study. This guidance is aimed at providing designers and researchers with both theoretical and practical design suggestions. Several research methods are included in this research study. Literature was reviewed to establish the theoretical basis for the empirical tests and relevant evaluation standards. Eye-tracking testing helped identify the map's strengths and potential design limitations in terms of information communication and visual design. It also assisted in observing users' reading strategies and habits based on the eye-movement data. The user performance tests helped evaluate the legibility of the existing map and the revised maps in terms of reading speed, information searching accuracy and route planning quality. The interviews and questionnaires helped collect users' opinions and suggestions, which reinforced the analysis of the experimental results. The results indicate that information design plays a vital role in transit map design in many aspects. The information communication quality of the map legend can largely affect the legibility of transit maps; users showed a faster reading speed and better information searching accuracy after the necessary instructions were visualised. The colour system showed its unreplaceable advantage in transit map visual design, especially in distinguishing and grouping different categories of travel information and map functions, such as different transit lines, services and icons, etc. In addition, a new colour-coding mode for transit lines that combines both qualitative and sequential schemes was created. Its effectiveness was then tested through usability testing. Users' reading speed and comfort were improved after the colour system was re-coded based on the new standard. This research also breaks Beck style (45°octolinear layout) in transit line schematical layout, widely recognised as "golden standard". The test results show that 60° octolinear layout could be the most suitable layout for the North-south direction middle-complex network. Moreover, the study shows that the visual design of micro visual elements (e.g., interchange icons, station labels) should always assist the information communication of the macro transit line layout. The test results would not be applicable to real-life contexts if the design of individual elements was investigated separately from the whole information design structure. The empirical research findings from this study are an essential contribution and a good demonstration that information design is of great importance to cartographic design. The study demonstrates a successful example that evaluated, improved and tested the legibility of a transit map by using existing information design principles and theories. The principles that then also emerge from this study are a strong contribution to knowledge in the field of information design and will provide valuable insight to researchers and designers. In addition, the methodologies used in the research can also support information design research beyond map design, such as information reading materials that contain various categories of instructions and data