Returning to previously visited pages after traversing the World Wide Web is challenging for most users in that they have to remember where they have been. According to a World Wide Web usability survey, revisiting pages is a main problem for users navigating the Web [8]. The survey reports that 13.41% of the users surveyed were not able to find pages already visited. In an attempt to facilitate revisiting pages and perhaps provide a significant addition to the "Back" feature, history mechanisms have been incorporated in Web browsers such as Netscape 4.0 and Internet Explorer 4.0 (IE). Overall the "Back" feature is not an efficient tool for revisiting Web pages because of such problems: (1) it does not contain all of the history, (2) the history is linear, (3) and the history is not saved in between sessions. A browser companion tool called PadPrints has also been designed to aid in revisiting pages by dynamically building a graphical history-map of pages previously visited [3]. PadPrints functions with a traditional Web browser without any necessary modifications to the browser. For the purpose of our experiment, history is defined as the collection of previously visited Web pages.

History keeping is a cognitive challenge because it is difficult to find a single visualization for the World Wide Web that would be most useful and effective for all users. We have not quite understood whether one history visualization, linear, tree-structured, textual, or graphical, will suffice or be more useful, or whether a combination of these history visualizations is necessary for Web navigation. In addition, we adopt the perspective that visual representations are data structures for expressing knowledge [5]. They help in problem-solving and discovery by providing a useful, efficient representation for expressing information. Cognitive efficiency occurs when perceptual inferences replace difficult cognitive comparisons and computations. Another related cognitive challenge is maintaining a sense of what you are looking at and where it is with respect to the rest of the data when navigating through large data spaces such as the World Wide Web [4].

The motivation for this study stems from a desire to assess the usefulness of history mechanisms in Web browsers. We hoped to learn about whether the history mechanism in one browser results in precise, efficient performance over another when revisiting pages. We also hoped to gain insight into what aspects of the history mechanisms are frustrating to users in an effort to suggest improvements for such features for future implementations.

Netscape’s history is a list of pages previously visited. The user is able to clear the pages in the history and specify a number of days after which the pages in the history should expire. The list can be sorted in ascending or descending order. The list can be viewed by title, location, first-visited page, last visited page, expiration or visit count. There is an option to search in the history list in which the user selects and specifies the parameters. The "Back" button, of course, is always an option, a time-consuming one if you have to go back several pages to get to the one you are looking for.

In addition to the "Back" button, Internet Explorer provides small downward arrows beside the "Back" or "Forward" button which allows you to see a list of the last few pages visited. From that list, the user is able to select a page. IE’s "History" feature has a list of folders that contain Web sites visited in previous days and weeks. By clicking on a folder or a URL, a page can be displayed. Like Netscape, the user can specify the number of days that pages are saved in the History list.

PadPrints displays a left-to-right hierarchical history of web pages visited [1]. A node in the hierarchy shows a title along with a small graphic of the page. The hierarchy is built as the user travels from one page to another. As users access pages from the web browser, those pages are shown in PadPrints. Unless the page is already in the hierarchy, pages are added as subnodes of the current node in the hierarchy. By clicking on a page in PadPrints, the corresponding page is displayed in the browser.

A previous study in Web navigation entitled, Revisitation Patterns in World Wide Web Navigation, reports that 58% of an individual’s pages are revisits and that users continually add new pages into their collection of visited pages [3]. This study also reported that people tend to visit pages frequently, browse in very small clusters of related pages, and generate only short sequences of repeated URL paths. After comparing various history mechanisms, it was concluded that the stack-based prediction method prevalent in commercial browsers is inferior to just showing the last few recently visited pages without any duplicates.

The purpose of our experiment was to observe navigation styles inherent in the history mechanisms of the browsers and browser tools. Our study focused on the history styles of Netscape 4.0, Internet Explorer 4.0, and PadPrints. We attempted to discover which tool’s history feature would provide for the best performance times in revisiting Web pages.

Another study, How Users Repeat their Actions on Computers: Principles for Design of History Mechanisms, made observations on how frequently users repeat their actions on interactive systems using usage data from many users over a period of months. The observation influenced the design guidelines specifically for history mechanisms and generally for current user interfaces. The focus was on the repetition of command lines and the probability of the next line given an ordered history list of previous commands.

Graphical versus textual representations of history put less emphasis on recall and more focus on recognition, facilitating revisiting Web pages and decreasing performance times. For this reason, graphical history mechanisms, such as the one used in PadPrints, will allow easier navigation when revisiting Web pages. A hierarchical page structure retaining the organizational and visual properties of pages along with their position in the hierarchy may improve recognition of a visited page and provide quicker access [10]. As the pages become smaller and smaller, especially highly textual pages, the visual properties might not provide any useful information.

In addition, we adopt the perspective that visual representations are data structures for expressing knowledge [5]. They help in problem-solving and discovery by providing a useful, efficient representation for expressing information.

We predict that the subjects will not complete the history-related tasks in a shorter period of time using PadPrints compared to Netscape or Internet Explorer. However, user satisfaction ratings will be significantly higher with PadPrints as a companion to either of the browsers.

Top | Credits | Introduction | Literature Review | Experiment | Results | Discussion | Conclusions | Acknowledgements | References | Appendices

Last Modified: May 11,1998