UI Design Newsletter – June, 2009

In This Issue:

Kang and Yoon watched older and younger people use a DVD player and MP3 device. They were interested in whether there was a difference in completing different tasks based on age. They also looked at whether familiarity and experience with such devices would have an impact on task success.

What I found most interesting about this research is that they didn't just watch people and then check off "Yes" or "No" for task completion. They observed and categorized the types of strategies and errors that people use when confronted with a device such as a DVD player or mp3 player.

Here's what they notated about strategies during their observations:

1. Systematic exploration – people are testing and evaluating hypotheses about how the device works and then making plans for the next action to take.
2. Trial and error – less logical than systematic exploration, people are trying various actions without a plan
3. Rigid exploration – repetitive actions without meaningful outcomes, people are doing the same things over and over even if they don't work; there is a lack of self reflection
4. Encapsulation – Focused information searching without an progress in task flow; people continue to search for information even though they aren't making progress in getting the task done

And here's what they notated about errors types:

A) Consequence – They noted 3 types of error consequences:

1. positive (action didn't give the desired result, was indeed an error, but provided information that helped the person achieve a goal)
2. negative errors (action resulted in a dead end)
3. neutral errors (there was no effect on progressing through the task)

B) Performance errors – They noted 3 types of performance errors:

1. commission errors are errors where a person did something that is incorrect, for example, pushing the wrong button
2. omission errors are errors were the person left out or missed a step or didn't press a button when they were supposed to
3. wrong action errors are errors where the person identified what they were supposed to do but didn't do it, for example the person says out loud which button is the right one to press, but then they press the wrong button

So in addition to seeing whether there was a difference between older and younger people in terms of task completion, Kang and Yoon also compared these different strategies and error types.

Here's what they found

Older people (ages 46-59) and younger people (ages 20-29) did not differ on task completion rate, but older people took more steps (and more time) to get the tasks done. This was not related to background knowledge or prior experience, but came from the fact that the older adults made more errors and used more rigid exploration.

Older adults:

• failed to get meaningful hints from the actions they took
• had more motor-control problems which meant they had more wrong action errors
• had as much past knowledge as the younger adults, but they often didn't use their past knowledge
• had a higher level of uncertainty about whether their actions were correct
• felt more time pressure and less satisfaction with the interaction experience

Older adults that did have less background and experience with electronic devices adopted more trial and error strategies.

Summary

This article suggests that we have to be more sophisticated when looking at differences between older and younger adults. We can't just assume that older adults will "have a harder time" with new technology. We need to parse out what "have a harder time" means. I think the categorization of strategies and errors that these researchers used is thoughtful and helps provide a clearer view of user strategy, thought process and errors.

References

Kang, Neung E. and Yoon, Wan C. Age and experience-related user behavior differences in the use of complicated electronic devices. International Journal of Human-Computer Studies, 66, 425-447, 2008.

If you are designing for older adults, it is not just about making the interface simpler and less dependent on technical knowledge. Since they explore in a "rigid" way, I would think it is most important to provide strong feedback for errors. So the error management needs to teach the older adult by indicating clearly that an error or failure has occurred, and then steer the older adult towards a better solution.