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Examining the Order Effect of Website Navigation Menus With Eye Tracking

Alex J DeWitt

Journal of Usability Studies, Volume 6, Issue 1, November 2010, pp. 39 - 47

Article Contents


Introduction

The order effect is a psychological phenomenon that has been observed since the beginning of the century. It describes a bias in the interpretation of a list of information depending on the order of presentation of that information. An early study on the subject found that content at the beginning of the list was learned better than that in the middle; dubbed the primacy effect, this is thought to be because items seen first are paid more attention and are observed by a fresh mind that has not processed any similar items yet (Deese & Kaufman, 1957). Additionally, the recency effect noted by Murdock (1962) describes items at the end of a list being recalled more accurately as they are still fresh in the reader’s mind.  

The order effect has evolved from the context of “learning” to that of “finding” information, for example, there has been an assumption in the fields of advertising and marketing that placing the most important facts at the beginning and end of a message will optimise its effectiveness amongst potential customers. It is also said to have impacted on political elections, accounting for an increase in votes for candidates at the top of the list (Alvarez, Sinclair, & Hasen, 2006).

The consideration of the order of items is also very much relevant to the design of software, websites, and mobile applications in terms of the architecture of the user interface and placing the most important functions where they will be located the most efficiently for the end user. With the increasing emergence and maturity of usability for exploring the ease of use of software, it is relevant to question the extent of the order effect in this domain. Looking specifically at websites, it is useful to know if indeed there is a significant impact on the navigability of the site depending on the order in which menu items are presented to the user.

This study used an empirical approach to explore the time taken for web users to acquire website navigation menu items by tracking their eye fixations in these areas. The aim was to establish if the placement of a link on a menu—its distance from the middle—affected the average time it took participants to discover it. The hypotheses were that (a) the psychological phenomenon of the order effect would manifest in that items at either end of a menu would be located more quickly than those in the middle and (b) that the items that were relevant to completing the participants’ tasks would be located more quickly through peripheral visual identification of these items

Prior Work

Work by Yu and Roh (2002) examined the effect of different menu designs on an otherwise unchanged website, but did not examine the order of menu items. They found that the user’s searching and browsing performance was affected by the type of menu and that the drop-down menu style yielded better searching performance than a global and local navigation menu or a simple selection menu. However, browsing was found to be fastest when using the global and local navigation menu.

Various studies have addressed the effect of breadth and depth of menu structure on speed and accuracy of task completion, for example, Kiger (1984; as cited in Zaphiris, 1997) experimented with five menu designs with varying breadths and depths of links and found that using a menu of four items each of which contained a sub-menu of 16 items showed the fastest response time with fewest errors. However, in these studies, the participants completed tasks on multiple menus with the same link names in a rotating order, so there may have been some learning effect as to which link name to click on. Additionally, the order of items within each menu was not addressed.

There was very little empirical work that gives guidelines as to the interpretation of eye-tracking data. The overall application of eye tracking to usability is explored in “Using Eye Tracking to Compare Web Page Designs” (Bojko, 2006). This paper used number of gaze fixations as a metric of efficiency to explain usability differences between web page designs and commended the reliability of eye-tracking data and its ability to examine the users’ information searching process rather than just the outcomes of such searches.

The only available study incorporating order effect and eye tracking was made by user experience consultants at Etre, who used eye tracking to examine heatmaps for five popular websites in 2006. They noticed “some evidence of ‘order effects’ in the processing of the left-hand navigation menu” (Etre, 2006, Our Findings section, para 5) on one of these sites. However, insufficient information was provided on their methodology, such as the number and type of participants in the experiment and what the context of looking at the web page was. Additionally, the heatmap was not classified as to whether it represents the number of fixations on menu items or the duration of these fixations. This highlights the need to pursue further research in this area.

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