Bad UI of the Week: The Mitten Mouse
Jef Raskin, user interface pioneer and father of the Macintosh UI, insisted that the Apple mouse only have one button because more than one would confuse the user. Anyone who has worked tech support and had to explain the concept of "right-clicking" will agree that this is, in many cases, valid.
In later years, he decided that humans had more than one finger, and so could deal with a multi-button mouse. He did place a conditional on this, however, saying that the buttons should be labeled with their use. Systems like RiscOS, where the left button was for selection, the middle for menu, and the right for alternative selection (typically rectangular rather than line-based) have borne this out.
So was the single-button mouse a mistake for the Macintosh? The single-button mouse certainly hasn’t harmed the machine’s market share to a noticeable degree. While it is still a minority platform, it is doing far better than most of the other systems dating from the same era that went for the multi-button approach.
Most power users, over the years, have bought third-party mice with multiple buttons. Even Apple now ships a multi-button mouse with the pro machines, but keeps the single button for the consumer line. What effect does this have on Mac software?
Mac users can right-click by holding Ctrl while they click, but this is not easy for all users. Left-handed users of Apple laptops, for example, have to cross their hands in a particularly uncomfortable way if they wish to press the Ctrl key with their right hand while using the trackpad with their left.
The biggest outcome has been that Mac software has all been designed on the assumption that there is only one button available. Over the years, the one niche which has always been faithful to the Mac interface has been the artist segment of the market. Is this because Macs foster creativity? Perhaps because you can’t be an artist with a PC? Or is it that a lot of artists favor a graphics tablet interface over a mouse, and a tablet only really allows one-button clicking ergonomically? Tapping the pen on the tablet simulates a click. Tapping while holding a button can be used for a right-click, but this is not particularly easy compared to using the left button.
The mouse, it turns out, is fairly rare among pointing devices in that access to both (or all) buttons is almost equally easy. This is not even true of the most common mouse replacements such as trackpads. Typically, the thumb rests on one button with these devices. Clicking the other requires moving it, sometimes even looking (moving your attention away from the screen) to check you are pressing the right one.
It is not surprising, then, that Apple has started to do well now that laptop sales are beginning to pass desktop sales; they get an interface that is easy to use with a single-button trackpad for free. The ultimate irony? The latest MacBooks have the first ergonomic mechanism for right-clicking I have found on a trackpad—holding down two fingers on the pad while clicking the button.
The moral of this story is that it is sometimes possible to design a good user interface by mistake. Most people would agree that the single-button mouse is a bad idea. It is not an effective use of the fingers that most people have. By forcing UI designers to work within the constraints of the single-button input device, however, the Mac interface grew to be very easy to use with a variety of other pointing devices. Something like RiscOS, which made good use of a three-buttoned mouse, would be much harder to use on a laptop, and almost impossible on a touch-screen.