Go Back One Step

Examples:

The "Back" button on a Web browser
The "Back" button on a wizard
Turning back a page in a physical book or magazine
The "Undo" feature on some computer applications

Context: The artifact allows a user to move through spaces (as in Navigable Spaces), or steps (as in Step-by-Step Instructions), or a linear Narrative, or discrete states.

Problem: How can the artifact make navigation easy, convenient, and psychologically safe for the user?

Forces:

Users tend to explore a navigable artifact in a tree-like fashion, going down paths that look interesting, then back up out of them, then down another path.
The user may want to temporarily look back at the previous space or state they were in.
If the user gets into a space or a state that they don't want to be in, they will want to get out of it in a safe and predictable way.
The user is more likely to explore an artifact if they are assured that they can easily get out of an undesired state or space; that assurance engenders a feeling of security.

Solution: Provide a way to step backwards to the previous space or state. If possible, let the user step backwards multiple times in a row, thus allowing them to backtrack as far as they want.

Resulting Context: Having a "back" function implies having a "forward" function; it's more of a convenience than a distinct pattern, but Web browsers have set up this expectation, so your users may be unpleasantly surprised if it's not there. Also, Go Back to a Safe Place is a logical pattern to use in addition to this one.

If the user knows they can step backwards multiple times, they may then expect that they can see the history through which they are backtracking -- in other words, their Interaction History.

Notes: A 1994 paper on the usage of Web browsers discovered that on average, the use of the "Back" button accounted for 40% of a user's actions. This was second only to following an actual link, which made up 52%. (In contrast, the "Forward" button only accounted for 2%.) Reference: "Characterizing Browsing Strategies in the World-Wide Web," by Lara D. Catledge and James E. Pitkow.

Comments to: jtidwell@alum.mit.edu
Last modified May 17, 1999