The original multi-tasking - shifting among subtasks in a compound activity

The August issue of Human Factors has a paper on multi-tasking that I think merits a detailed look. At first, I thought it was another one of those “distracted by technology” studies.  When someone does a better study than Clifford Nass at Stanford (quick PBS interview here or his lab’s page here) I am ready to read it.

But this paper by Brent Morgan at the University of Memphis and his colleagues at Notre Dame were looking at compound tasks– that require the user to do multiple tasks simultaneously.   They used a cockpit simulator but you can imagine different examples in health care and many others.  The basic result of their study is that at lower (easier) levels of multi-tasking, having a good working memory capacity is all you need to multi-task (assuming you have the necessary task-specific skills to do the individual components effectively).  But as the difficulty increases and you get to the maximum of your working memory, having really good task skills becomes more important.  It is these skills that help you effectively shift among sub-tasks in the optimal way as their importance and urgency shifts.  To be frank, this isn’t really that earth shattering, but it is an important study because it puts some certainty behind what many designers might expect and adds some details and refinement.

But what I found most interesting is their speculations at the end.  They suggested a few different multi-tasking “profiles” that I found really intriguing.  First, individuals might have dispositional strategies for multitasking. 

There are some people who are “consistent” multi-taskers.  As difficulty increases, they try to keep up with all of the sub-tasks.  Some are good at it and some are poor at it, but they are consistent across the task list.

There are some people who are “attackers.”  As difficulty increases, they focus more on the hardest tasks and less on the easier ones.

There are some people who are “avoiders.”  As difficulty increases, they focus more on the easier ones and less on the harder ones.  You can get more things checked off your list, but perhaps not the most important ones.

Then we can look at it by context.  Are there some contexts that motivate users across the board to focus on the harder or easier tasks or to be consistent across the board?  Perhaps through incentives?  Or perhaps by good transparency in designing importance and urgency indicators in the UI?

We can also look at the importance of this concept for team building.  If you are putting together a team, is it important to match people who will agree on what needs to be done (all avoiders or all attackers) or is it better to have a diverse group who will naturally gravitate towards different sub-tasks and hopefully all of them will get done?  I don’t know the answer to this one, but I find it really intriguing and important to find out.  Hopefully, a future issue of Human Factors will reveal the answer!!