Using Impenetrable Borders in a Graphical Web Browser: Are All Angles Equal?

Impenetrable borders can be created by placing graphical user interface targets (e.g., buttons, scroll bars, etc.) on the edge of a computer display. Research demonstrated that targets with impenetrable borders (edge targets) are selected faster than targets of the same size that are not against the edge of the screen (non-edge targets). This paper discusses the reasons why edge targets are selected faster than non-edge target and points out a critical weakness in past research on impenetrable borders. Specifically, researchers have always placed targets at a 90° angle from the cursor's origin, thus forgoing any ecological validity. Accordingly, an experiment is reported that tests the effectiveness of impenetrable borders when approach angle varies on a graphical web browser interface. Results indicate that impenetrable borders are effective across all of the approach angles used. These results support the recommendation to place commonly used targets at the edge of the screen whenever possible.