This year I will finally be able to put some effort into PDQMac.com, the site I’ve set up with the aim of improving people’s interface productivity. If there’s a key underlying point to what I’ll be doing with that site, it is this:

Productivity is all about muscle memory.

So I’d better explain what that means before I go any further. Let’s start with the fact that nearly all of us have learned how to drive a car and have a memory of that learning process. There are quite a few physical things that have to be learned in order to drive a car that you simply did not know before you started to drive; including managing the accelerator, brake, steering, winkers, and stick-shift (if you learned on a stick-shift car.) You were, no doubt, told how all of these controls worked, but you couldn’t drive properly just because you knew how to with your thinking brain. You had to keep practicing until your body learned how to use these controls. And nowadays, years after, you never think about most of the controls or how you use them because they are perfectly stored in your “muscle memory.”

Muscle memory is the automation of behavior and most of what we do, including for example, how we pronounce words, involves muscle memory. As regards computer interfaces, the simple truth is that the PC interface has not been designed with muscle memory in mind. In fact, at times it seems to be designed almost to defeat muscle memory. So let’s forget that abysmal interface for the moment and talk about interfaces that are built with muscle memory in mind.

1. Guns and Fighter Planes. You may have noticed that an AK47 has no drop-down menus. Does that surprise you? The popularity of the AK47 (I’m no gun expert by the way) is generally that it’s dependable, easy to maintain and the interface is true point and shoot. Although fighter planes are far more complex than guns, the design of fighter planes follows the same principle. You really don’t want the pilot who is caught in a dogfight to be wandering whether the “Shoot Cannons” command is on the Format Menu or the Tools Menu.
2. Cars. Once Ford got the driving interface buttoned down on the Model T, all cars that came after adopted very similar interfaces, to the point where now, when you change cars, your learning curve is minimal – usually a few minutes. A software writer I know, whom I’ve discussed this topic with at length, tells me that it took a few attempts to get the Model T right, with the first model T using controls that were based on farm machinery. Notice how much more of a learning curve can be involved when a major revision of Windows or MS Office occurs. Sometimes users even have to be retrained.
3. Games Machines. Luckily we have games machines to prove indisputably that computer interfaces can be very productive. And notice how successful both the iPhone and the Wii have been, partly I suspect because they’ve added interface features that are very effective in terms of muscle memory.

This gets me to the point where I think I can define what a “muscle memory interface” is:

It is one that is built so that controlling the device or environment can be done with minimal need to engage the thinking part of the brain.

The very fact of the keyboard and mouse, and the need to switch between them makes it very difficult to establish muscle memory in some usage contexts and in other contexts, the tendency is for the user to remember really slow ways to do things. Yes, actions get committed to muscle-memory, but the outcome is not productive.

The software writer I mentioned above (Tim Negris) has written an application for manipulating photos. It runs on Windows and every effort has been made to design it with muscle memory in mind. Over the next few days I will be using it and I’ll give it a full review when Ive used it enough to comment on its interface.