Posts Tagged ‘feedback’

Wednesday Wii: Bad Indicators

March 10, 2010

A key rule in designing user interfaces, particularly for control systems, is that they should make it clear to the user what the current state of the system is. This is particularly important in training systems, because you want the user to learn the right thing. The “line and bar” indicators in many of the Wii Fit exercises are bad indicators because they don’t provide the right feedback, and the scoring system is flawed because its response range is too narrow.

In a typical line and bar exercise, like the Lunge, you increase the weight on the Wii Fit board to drive a red bar up until it hits a blue line. Depending on the amount of control you are expected to have, you either hold the top of the bar inside the (wider) line, or you simply drive ahead until you cross the line. Conceptually, this is a good way to learn to control your weight placement and to encourage you to learn the physical moves (deep knee bends, deep upper body bends) needed to do so. In practice, there are two problems:

1. In some exercises, like the Spine Extension, you can’t see the line and bar, because you are bent over, or are facing away from the indicator. Nintendo tried to solve this with an audible signal. If you are outside the bar you hear a steady drumbeat. If you are inside the bar the sound changes to a bell, that slowly fades away as you reach the center. Unfortunately, the sounds don’t differentiate between being over or under the bar, I think — there may be subtle tonal differences that I can’t pick out over the voice of the trainer telling me to count with her. Normally, you would think this isn’t a problem. When you are as out of shape as I am, it’s rare that you can even hit the bar, let alone overshoot it. Except that there are exercises and poses where I tend to undershoot when my right foot is forward, and overshoot when I use the left. This is particularly a problem when I have to cheat, say, when I bend my knee instead of stretching my sciatic nerve three inches longer than it was designed to be. So, why would I want to cheat? Don’t the cute girl in spandex, and the handsome frat-jock with the mullet keep telling me to maintain good form at all costs? Read on.

2. Still reading? Good. The second problem I have with the line and bar is that you don’t get any score unless you have crossed or come very close to the line. No score. Zero. How can I tell if I am improving if I can’t compare my scores? My form may be exquisite, but am I getting that extra half-inch compared with last week? If I cheat slightly, get closer, maybe just enough for the bar to kiss the edge of the line and switch back and forth from bell to drum, then maybe I can get enough of a score that I can start seeing progress. (I’ll talk more about this in a future post.)

The solutions? Well, why not try using a different tone, depending on if you are high or low? In fact, why not try using an actual tone instead of a drum? That way I won’t have to wait a couple of beats for my brain to kick into gear. In the early days of radio beacon navigation, you heard dashes if you were on one side of the beam, and dots if you were on the other, and they combined into a solid tone when you were right on. This meant you had a continuous confirmation that you were on course. On the Wii Fit, you get silence. Does silence mean you are where you need to be, or does it mean the sound card has failed. Should I look up and see? Secondly, give points for effort. Not a lot. But if I grunt and wheeze and move the red line a third of the way up, then give me a point, or a tenth of a point. With those two changes I will be able to keep my head down, or sideways, or whatever, and concentrate on my form, knowing that I will be guided to the proper place and that I will be able to track my progress as I go. Is that too much to ask?