Take It Down a Notch

There's this guy at the CVS I frequent who is amazingly efficient at checking out customers. So efficient, in fact, that it's actually somewhat jarring. The moment I start to put my stuff on the counter he immediately asks for my CVS card, but I don't even have my wallet out yet! The actual scanning happens at light-speed, and as soon as that receipt touches flesh it's time to move, because he's already starting the process with the next hapless patron.

As far as time per checkout, this guy could probably win a contest. However, this doesn't lend itself to a very pleasant user experience. I get performance anxiety whenever he checks me out -- what if I can't fish my card out fast enough? can't situate my 12-pack in time? or type in the wrong pin? -- and even when there's a line, I'd rather he just slow down a bit.

Could this ever be the case in interaction design, where efficiency is often preached as a key metric of overall usability? I'm not arguing for designers to intentionally create inefficient experiences, but I do think that sometimes incorporating a brief pause can help the user understand what's happening. Especially in computer applications, where some actions can be processed instantaneously, it can be hard for a user to follow rapid changes on different parts of the screen. This, in turn, can make it tougher to understand causality and create a valid mental model of the system.

Inserting a brief pause gives the designer just enough time to make a changing item blink once, to scroll a list instead of jumping to the end, or to have an item animate into a shopping cart instead of magically teleporting there. These visual effects are one of my favorite applications of web 2.0 technology because they allow designers to change traditional hypertext (a series of instantaneous pages) into a richer, animated experience with vastly more behavioral cues.

Now, if only I could get a "CVS guy 2.0" that would just settle down a bit at the counter...