Eye Tracking Web Usability

This research seeks to obtain a deep understanding of the cognitive factors and the CCIRs in the customer’s DMP that influence online hotel reservations. Ocular indices (i.e.

MyTobii Eye Tracking Device) enable researchers to determine what abstracts a computer user is indeed reading and viewing, for how long and in what order. This gives the researcher the opportunity to extract more accurate conclusions regarding hotel websites and what actually a potential client sees and what makes him to go to another hotel website for his booking.Eye tracking is possible to trace a lot of CCIRs used and required during the decision making process of any task (i.e. hotel booking). It is a useful tool in order to open the ‘black box’ of online decision making and to study the computational processes used by participants to make these decisions (Willemsen and Johnson 2009).

Rayner (1998), cited in Granka et al (2004), states that eye fixations are defined as a spatially stable gaze lasting for approximately 200-300 milliseconds, during which visual attention is directed to a specific area of the visual display. Fixations represent the instances in which information acquisition and processing is able to occur and thus, fixations are the indices for the evaluation of this research.

According to Ofcom Research Document (Ofcom, 2009), decision making can be the result of two separate mental processes:

a. Reasoned decision making: bring to mind previous experiences and their conscious evaluation. For the purposes of the research, Critical Decision Method is going to be used.

b. Heuristic decision making: in order to analyze the heuristic part, Applied Cognitive Task Analysis in combination with Eye Tracking Device (MyTobii) is going to be used.

Following, Kominkova (2008); Haddioui and Khaldi (2011) eye tracking is the process of measuring either the point of gaze ("where we are looking") or the motion of an eye relative to the head. According to MyTobii user manual, MyTobii eye control system allows a research respondent to interact directly with objects (i.e. websites) on a computer screen simply by looking at them. MyTobii is based on an eye tracking technology, which keeps track of the user’s gaze as well as the location of objects on the screen and estimates what actions the user intends to initiate based on the eye movements.

90 Tracking people’s eye movements benefit Human – Computer Interaction and researchers to understand visual based information processing and the factors impact the whole process. According to Goldberg and Wichansky (2003), most commercial eye-tracking systems available today measure point-of-regard by the “corneal- reflection /pupil-centre”

method. Poole and Ball (2005), eye trackers usually consist of a standard desktop computer with an infrared camera mounted beneath (or next to) a display monitor, with image processing software to locate and identify the features of the eye used for tracking. In operation, infrared light from an LED embedded in the infrared camera is first directed into the eye to create strong reflections in target eye features to make them easier to track. The light enters the retina and a large proportion of it is reflected back, making the pupil appear as a bright, well defined disc (known as the “bright pupil” effect). The corneal reflection (or first Purkinje image) is also generated by the infrared light, appearing as a small, but sharp, glint (Figure below).

Figure 24: Corneal reflection and bright pupil as seen in the infrared camera image

Source: Haddioui and Khaldi (2011)

Calibration of the equipment is necessary because there are differences in the size and shape of individuals’ eyes. It is proposed that calibration should be repeated throughout testing to maintain an accurate record (Poole and Ball, 2005, Haddioui and Khaldi 2011).

Large offsets (long green lines, Figure below) can be caused by various factors such as, the user not actually focusing on the point, the user being distracted during the calibration or the eye tracker not being set up correctly. It is important that a video camera was recording the entire process of the participants in order to give control to the researcher and in order to capture any un-said cues.

91 Figure 25: The Tobii x50 can do eye tracking at gaze angle up to 35º out from the center of the built in camera

Source: www.tobii.com

6.8.1 Apparatus: The research was performed with a Tobii x50 eye tracker that should be placed below the screen (or the surface that is to be studied), vertically aligned with the center of the screen, horizontally aligned with the screen in two directions (thereby leaving only one angle of rotation allowed), placed as close below the screen as possible, placed so that the person sitting in front of the eye tracker will sit at an approximate distance of 61 cm (or 24 inches) from the eye tracker, placed so that the gaze angle of the person being eye tracked never will exceed 35º as long as he looks at the screen, this allows for eye tracking on a 21” TFT screen if the Tobii x50 is set up right in front of this screen (tobii.com). As a result, the participants could move freely in the limited area that the tracking system can record their eye movements.

Eye Tracking tests were performed in Psychology Laboratory of European University, Nicosia (Figure 26). The Laboratory is divided into two rooms with a window in the middle. One of them is the Tobii Room, having a computer with an eye tracker device and screen recording capabilities (Model Tobiix50), a conference table that interviews, brain storming and other surveys are prepared. The other room is the operator room, where the participants and the screen of the Tobii test are observed. Additionally, this room has microphones, amplifiers and computers for further analysis. It is important that Tobii room is soundproof. Moreover, a video camera was used so as to capture as much information as possible during recording and to capture all think aloud data from respondents.

92 Figure 26: Psychology Laboratory of European University, 2010