Applying Hick’s Law to the Firefox context menus
23 July, 2012 § 25 Comments
Almost exactly a year ago I wrote about applying Fitts’ Law to commonly used buttons. Fitts’ Law is pretty well known among user experience professionals and front-end developers as it can be used to make commonly accessed user interface elements much easier to target. Hick’s law is probably less known, but its effectiveness is just as great.
Hick’s law “describes the time it takes for a person to make a decision as a result of the possible choices they have.” This law can be applied to the number of options for a question on a form, the number of dishes offered on a restaurant menu, as well as the number of menu items on a context menu.
In the case of Firefox’ context menus, we were able to remove a very seldomly used menuitem (“Send Link…”), and combine the “Reload” and “Stop” buttons.
Our new heatmap data showed us that only 0.89% of users clicked on the “Send Link…” menuitem. This is not really a surprise, given that the location for the majority of webpages can be found by looking at the location bar. This is in contrast with “Send Image…” which was used by 3.34% of users. “Send Image…” likely has higher usage because the majority of image URLs are not available in the primary UI.
Combining “Reload” and “Stop” gives us another nice win because the two states are mutually exclusive and the combination reflects the default state of the two actions in our location bar. Making this change led to discussions about removing the “Forward” menuitem when it is disabled, similar to how we remove the Forward button in the navigation toolbar when it is disabled. While removing the “Forward” menuitem would align with internal consistency, it would also make the remaining menuitems more ambiguous (“Back” and “Reload”).
The disappearance of the Forward button in the navigation toolbar does not make the Back button ambiguous. The back button is visually connected to the location bar (signifying a relationship between the two items), and the arrow describes moving backwards. If the context menu only contained “Back” and “Reload”, or potentially “Back” and “Stop”, then there is a much greater chance of confusion as to what “Back” really does. In other words, the presence of “Forward” helps to provide a navigational context for the other menuitems in their group.