BHR 4: Full UI Standardized Microwave Raquel Dottle and Virginia Pettit
Prototype Version II:
User Profiles: Age Range
Gender
Ethnicity
Occupation
Frequency of Microwave Use
User 1
10-14
Male
White
Student
Daily
User 2
40-49
Male
White
Service Job
Daily
User 3
20-25
Male
White
Student
Weekly
Experiment: What we did: Based on the repeated difficulties users had, we cut out half the buttons, put all the “clutter” functionality in one unobtrusive place, and switched to a dial to minimize the different context slips users would make. We also decreased the size of our prototype to be closer to a real microwave. Finally, we increased the size of the “start” and “cancel” buttons to follow Fitt’s law.
What they did: Users on the whole responded better to this version than any other. We noted significant improvement in number of errors, and less frustration overall. There wasn’t much feedback about the change from a number pad to a dial, but this change removed the confusion we had seen about how to start the microwave. On the whole, users seemed less “lost”; they were able to bridge the gulfs of execution and evaluation much faster than we had seen in previous versions.
Scenarios and test proceedings: Scenario 1: You have some leftover pizza you just pulled out of the fridge that you want to eat. Please show me how you would heat that up. User 1: User paused a while, looking at the buttons a bit confused, then said, “Where’s the time cook? I usually have to press time cook.” He then pressed +30 twice and then pressed start. The microwave then ran for a minute. User 2: He turned the dial clockwise to 45 seconds and then pressed start. User 3: User stated he had no idea how long pizza should go in for. He then turned the dial clockwise to 40 seconds then pressed start.
Scenario 2: You’re making a boxed dinner that has instructions to cook it for 2 and a half minutes. Please do that. User 1: He turned the dial clockwise to 2:30 and then hit start. User 2: The user stated “I usually just hit the 3 button and stop it when it’s done… but there’s not buttons on this one.” He then turned the dial clockwise to 2:30 and pressed start. User 3: User hit the +30 sec button 5 times and then hit start.
Scenario 3: The power went out in your house last night. You need to set the clock on your microwave to the current time. User 1: (Time: 7:30 PM) The user turned the dial clockwise until it reached 7:30 minutes, then hit clock, where it reset to 12:00 AM. He then said “Oh, right! I should have hit the clock button first!” he then turned it clockwise to 7:30 PM. User 2: (Time: 8:00 PM) User hit the clock button and started to turn the dial clockwise, seeing it go from 12:00 AM to 1 AM, 2 AM, etc. He then turned it counter-clockwise to 8:00 PM, remarking that he hopes it goes faster backwards the faster he turns because it would get tedious otherwise. User 3: (Time: 11:00 PM) He hit the clock button and then turned the dial clockwise to 11:00 PM.
Summary of results: It appears that our modified dial and fewer buttons improved user’s experiences with this machine. There were far fewer slips and mistakes, and many users had smaller gulfs of evaluation. However, they didn’t use the additional features at all.
Suggestions for change: Maintain the dial format, because it appears that users find it simplest to use. Figure out a way to balance the additional functionality with discoverability- perhaps some sort of chart? It might be possible to rely on the curiosity of the user to push the button, as those who enjoy that functionality probably would. A/B testing would be beneficial to test changes like this; however,
from a comparison to previous results, this version seems to be the most successful in minimizing user confusion and errors.