Eye-tracking applications are surveyed in a breadth-first manner, reporting on work from the following domains: neuroscience, psychology, industrial engineering and human factors, marketing/advertising, and computer science. Following a review of traditionally diagnostic uses, emphasis is placed on interactive applications, differentiating between selective and gaze-contingent approaches.

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A breadth-first survey of eye-tracking applications

This paper presents a general theory for the remote estimation of the point-of-gaze (POG) from the coordinates of the centers of the pupil and corneal reflections. Corneal reflections are produced by light sources that illuminate the eye and the centers of the pupil and corneal reflections are estimated in video images from one or more cameras. The general theory covers the full range of possible system configurations. Using one camera and one light source, the POG can be estimated only if the head is completely stationary. Using one camera and multiple light sources, the POG can be estimated with free head movements, following the completion of a multiple-point calibration procedure. When multiple cameras and multiple light sources are used, the POG can be estimated following a simple one-point calibration procedure. Experimental and simulation results suggest that the main sources of gaze estimation errors are the discrepancy between the shape of real corneas and the spherical corneal shape assumed in the general theory, and the noise in the estimation of the centers of the pupil and corneal reflections. A detailed example of a system that uses the general theory to estimate the POG on a computer screen is presented.

General theory of remote gaze estimation using the pupil center and corneal reflections

Effective visual design of e-commerce websites enhances website aesthetics and emotional appeal for the user. To gain insight into how Internet users perceive human images as one element of website design, a controlled experiment was conducted using a questionnaire, interviews, and eye-tracking methodology. Three conditions of human images were created including human images with facial features, human images without facial features, and a control condition with no human images. It was expected that human images with facial features would induce a user to perceive the website as more appealing, having warmth or social presence, and as more trustworthy. In turn, higher levels of image appeal and perceived social presence were predicted to result in trust. All expected relationships in the model were supported except no direct relationship was found between the human image conditions and trust. Additional analyses revealed subtle differences in the perception of human images across cultures (Canada, Germany, and Japan). While the general impact of human images seems universal across country groups, based on interview data four concepts emerged--aesthetics, symbolism, affective property, and functional property--with participants from each culture focusing on different concepts as applied to website design. Implications for research and practice are discussed.

http://ftp.misq.org/skin/frontend/default/misq/pdf/appendices/CyrHeadAppendices.pdf

Exploring human images in website design: a multi-method approach

Colour has the potential to elicit emotions or behaviors, yet there is little research in which colour treatments in website design are systematically tested. Little is known about how colour affects trust or satisfaction on the part of the viewer. Although the Internet is increasingly global, few systematic studies have been undertaken in which the impact of colour on culturally diverse viewers is investigated in website design. In this research three website colour treatments are tested across three culturally distinct viewer groups for their impact on user trust, satisfaction, and e-loyalty. To gather data, a rich multi-method approach is used including eye-tracking, a survey, and interviews. Results reveal that website colour appeal is a significant determinant for website trust and satisfaction with differences noted across cultures. The findings have practical value for web marketers and interface designers concerning effective colour use in website development.

/pdf/colour-appeal-in-website-design-within-and-across-cultures-a-37j0u9uc1t.pdf

Colour appeal in website design within and across cultures: A multi-method evaluation

An eye tracking study was conducted to evaluate specific design features for a prototype web portal application. This software serves independent web content through separate, rectangular, user-modifiable portlets on a web page. Each of seven participants navigated across multiple web pages while conducting six specific tasks, such as removing a link from a portlet. Specific experimental questions included (1) whether eye tracking-derived parameters were related to page sequence or user actions preceding page visits, (2) whether users were biased to traveling vertically or horizontally while viewing a web page, and (3) whether specific sub-features of portlets were visited in any particular order. Participants required 2-15 screens, and from 7-360+ seconds to complete each task. Based on analysis of screen sequences, there was little evidence that search became more directed as screen sequence increased. Navigation among portlets, when at least two columns exist, was biased towards horizontal search (across columns) as opposed to vertical search (within column). Within a portlet, the header bar was not reliably visited prior to the portlet's body, evidence that header bars are not reliably used for navigation cues. Initial design recommendations emphasized the need to place critical portlets on the left and top of the web portal area, and that related portlets do not need to appear in the same column. Further experimental replications are recommended to generalize these results to other applications.

Eye tracking in web search tasks: design implications

Computer interface evaluation using eye movements: methods and constructs

Evaluation of the computer interface is traditionally conducted via checklists, task scenarios, walkthroughs, heuristics and other subjective techniques. Analysis of user's eye movements during user interaction can add more objectivity to these evaluations. The objective of this study was to determine if eye movement behavior is influenced by interface design quality in a manner that can be characterized and used to identify design weaknesses. Eye movement scanpaths were collected from 12 subjects interacting with 4 interfaces utilizing different component grouping strategies. Interface quality ranged from “excellent” to “unacceptable”, as assessed by 50 typical users and 30 interface designers. A series of quantifiable measures were developed to characterize the resulting scanpaths. These measures examined raw scanpath data, fixations and saccades, and their interaction on both a temporal and spatial basis. The measures proved to be good indicators of interface quality. The “good” grouping strategy resul...

Eye Movements and Interface Component Grouping: An Evaluation Method:

This research investigated the feasibility of using eye movement behavior to evaluate computer interface usability. Eleven eye movements measures were used to quantitatively assess interface quality and compared to established usability ratings. Experiments were designed to manipulate interface quality along one of three design concepts: Component Grouping, Representation and Visibility. The interfaces were deliberately designed to provide a range of usability from 'good' to 'poor'. Fifty typical users and thirty industry interface design experts rated interface usability, establishing benchmark assessments for comparison.
The Grouping Experiment presented interface layouts that increasingly mismatch user expectations of component position. Scanpath measures associated with search were significantly (p $<$ 0.05) greater as subject expectations increasingly failed to be met. The Representation Experiment manipulated component representations. Scanpath measures indicative of the extent of information processing significantly (p $<$ 0.05) increase as component representation became inherently less meaningful or distinct. Search related measures also increased as meaningfulness decreased.
The Visibility experiment manipulated the salience of target components relative to other components in the interface. As target component salience increased, search related measures were expected to decrease. However, the majority of the measures were not significantly influenced by component salience (p $>$ 0.05). The lack of effect may have been due to the narrow range of quality differences between the interfaces, suggesting a limit to the sensitivity, not the validity of the scanpath measures.
Factor analysis of the eleven measures resulted in the separation of scanpath measures into three groups: Global Search, Local Search and Processing. A reduced set of six measures was identified as the minimal set that could still quantify the varied spatial and temporal aspects of a scanpath.
Overall, the relative quality assessment based on eye movements corresponded well with the initial usability ratings, providing sufficient evidence for the validity of eye movement characterization as an interface evaluation methodology.

Xerxes P. Kotval

Papers

Computer interface evaluation using eye movements: methods and constructs

Eye Movements and Interface Component Grouping: An Evaluation Method:

Eye movement based evaluation of human-computer interfaces