- Learnability. The main problem caused by this microwave is the way the fast mechanism works on the controls. For a long time, microwaves would take in the numbers pressed as arguments for the overall time. For example, if you pressed 1 that would input 1 second, and then if you pressed 2 after, it would be 12 seconds. However, with this new mechanism, inputting 1 immediately causes the microwave to start heating up for 1 minute. Although there is small text specifying that these numbers are “One touch start”, said text is small and barely noticeable. I, as a user, had not taken note of it until now. Regardless, it goes again the intuition provided by microwave button affordances: the idea that, with any user interface, the buttons pressed introduce themselves as a continous sequence of numbers. Moreover, it is not expected for a microwave to start cooking if the start button has not been pressed.
- Safety. This change in button behavior introduces a risk in safety and errors. Users are more likely to cook their food for a longer amount of time than is needed, which is irreversible. When using the microwave, I simply stop the time when the amount I originally wanted has elapsed. This introduces space for a multitude of errors.
- Efficiency. Regardless, the mechanism does benefit the efficiency dimension for the microwave’s usability. Having the “One touch start” saves the user a considerable amount of time, rather than having to write “1-0-0” and hit “Start”.
Potential Solution. The main approach to resolve this problem would be to have an optional, pressable “express” option, that allows immediate cooking after the press of a number if activated. However, this would take away from the efficiency benefit of the “One touch start”, as It would now require two steps. Regardless, it is still more efficient than entering a series of numbers, and it would not disturb the regular functionality of the microwave.