The Amazon Kindle Illustrates the Degradation of “Back”

The Kindle’s user guide states that readers can use Back to return to their book or magazine after briefly looking up a word, highlighting text, or following a footnote: “Pressing the Back button, located to the right of the select wheel, will bring you back to where you were.” But the nature of hypertext is fundamentally associative. Once we have linked away from our book in the Kindle and looked through several pages in several new texts, what does it mean to go “back” to where we were?

The Amazon Kindle received its share of criticism for “Next Page” and “Prev Page” buttons that are too easy to press unintentionally. But it is the Kindle’s “Back” button that illustrates the fissure that opens up when there is a mismatch between mental and conceptual models. How does “Back,” on a device that promotes itself as a book substitute, fit into our mental models of reading?

A reader leaves a book to browse the Kindle store. Once there, she selects a top-level category, such as blogs, then a subcategory, like news, politics, and opinion, and then uses Next Page and Prev Page to look through several pages of available blog subscriptions. Where should Back now take her? To the home page of the Kindle store? To the page listing all blog subcategories? What about back to the page of the book she was reading? In this scenario Back takes her to the list of blog subcategories, from which she had previously selected news, politics, and opinion. But it is difficult to imagine a rationale for this behavior that would help her predict the results of using Back in future contexts.

The Kindle’s Back button represents a collision between what we have learned in the past 500 years about reading books, and what we know so far about hypertext. Consider what the Kindle user’s guide says about underlined words in a text: “They indicate a link to somewhere else in the material you are reading like a footnote, a chapter, or a web site.” A typical mental model of book reading includes the concept of a footnote and a chapter as being “somewhere else in the material you are reading,” but a website is something else altogether. We put down our books when we look something up on the Internet. If we are reading online, we know we are leaving the current text when we link to another site.

September + October 2008

Back is a flawed concept for the Kindle because it mixes two separate mental models of reading (Web and print), and because Back is hardly a settled concept for Web-based interactions in the first place. Initially, Back was simple to understand and use. The predictability of Back and Forward made risk taking more acceptable for new users. But the No. 1 “design sin” in Jakob Nielsen’s “Top Ten Web Design Mistakes of 1999” was the breaking of Back by coding links so that they open new browser windows or redirect users to the undesired page. Over the years, Back has been degraded further by the use of frames; by forms that send a user’s information to a server for processing; by websites that use Flash animations for navigation; and by rich Internet applications that process information within the context of a single URL.

interactions

These “contingent” implementations make it difficult for users to develop mental models that will allow them to predict what will happen when they use a Back button, whether on the Web, the Kindle, or any other device.

account regardless of the authorization method. But the fact that the choice of authorization method is disguised as a choice of payment account (credit or checking) is damaging to the customer’s efforts to build an understanding of the way their everyday transactions work. The misleading system image confounds learning and understanding.

If you have made the necessary mental accommodation and you understand why you should select credit when you want debit, you might think you understand what happens when you enter a PIN to authorize a credit transaction when that is the default at the checkout. You simply use the same PIN that allows you to take a cash advance from your credit card at an ATM, for example. You are merely choosing to authorize the transaction with your PIN rather than with your signature. But sometimes “credit or debit?” does mean just that: Some credit cards are actually “dual access” cards and can be used as debit cards attached to checking accounts at the issuing bank. The cards themselves do not indicate this dual functionality, and the system provides no indication that in choosing to authorize the transaction with a PIN instead of a signature, the customer is actually requesting that the funds be taken from her checking account rather than her line of credit. The customer has every reason to believe that she is making a credit card purchase, but her choice of PIN-based authorization makes it a debit transaction instead. And of course it is overly generous to call this a “choice,” since the sys-