How many controls does a device need? The fewer the controls the easier it looks to use and the easier it is to find the relevant controls. As the number of controls increases, specific controls can be tailored for specific functions. The device may look more and more complex but will be easier to use.
We studied this relationship in our laboratory … We found that to make something easy to use, match the number of controls to the number of functions and organize the panels according to function. To make something look like it is easy, minimize the number of controls.
How can these conflicting requirements be met simultaneously? Hide the controls not being used at the moment. By using a panel on which only the relevant controls are visible, you minimize the appearance of complexity. By having a separate control for each function, you minimize complexity of use. It is possible to eat your cake and have it, too.
Whether with cake in hand, mouth, or both, I would note that easy saying is not necessarily easy doing. There’s still a considerable amount of art in making that heuristic work for any specific situation.
One aspect of that art is deciding what functions it makes sense to expose at all. Fewer functions means fewer controls and less apparent complexity. Catherine Powell’s Customer-Driven Knob was revelatory for me on this:
Someone said, “Let’s just let the customer set this. We can make it a knob.”
Okay, yes, we could do that. But how on earth is the customer going to know what value to choose?
As in my first post about The Design of Everyday Things, I find myself drawn to comparisons with The Shape of Actions. In this case, it’s the concept of RAT, or Repair, Attribution and all That, the tendency of users to adapt themselves to accommodate the flaws in their technology.
When I wrote about it in The RAT Trap I didn’t use the word design once, although I was clearly thinking about it:
A takeaway for me is that software which can exploit the human tendency to repair and accommodate and all that – which aligns its behaviour with that of its users – gives itself a chance to feel more usable and more valuable more quickly.
Sometimes I feel like I’m going round in circles with my learning. But so long as I pick up something interesting – a connection, a reinforcement, a new piece of information, an idea – frequently enough I’m happy to invest the time.