In The Oxymoron of Fast Food and Phone Jacks (or was it Phast Phood and Fone Jacks), I alluded to multitasking, and the potential problems associated therewith. While doing some research on fast food, I was simultaneously researching “multitasking”. I found three fascinating pieces on the subject, although I was not terribly surprised by the conclusions stated therein. (Can you believe I used “therewith” and “therein” in the same paragraph? That’s not easy to do!)
So while writing a critique of multitasking in “Oxymoron”, I was doing my own bit of multitasking. And here are the results – three different but related rules associated with multitasking.
Rule #1: There are limits to what you can do at the same time!
There’s the old story about the guy who could not walk and chew gum at the same time. Most of us can do both of these things simultaneously, but everyone has limits.
A John Hopkins University psychology study suggests that a person’s attention is strictly limited. When attention is deployed to one modality (such as talking on a cell phone), it necessarily extracts a cost on another modality (such as driving a car). It’s a classic zero-sum game – the more you focus on one, the less you are able to focus on the other.
This study wired up the brains of some healthy young adults. The subjects viewed a computer display while listening to voices over headphones. When the subjects directed their attention to the visual tasks, the auditory part of the brain recorded decreased activity. Similarly, when they focused on the sounds from the headphones, the visual parts of the brain decreased in activity.
This study suggests that hands-free cell phone devices are not the answer. The problem is not the hands. It’s the brain.
Rule #2: With multitasking, you must expand, not contract, the completion deadline!
Here is a workplace scenario that has happened to us all. Your boss (or your client or your customer) gives you a project which should take about a half-day to complete. He or she is then upset when the project is still not complete two or three weeks later.
It’s not that you slacked off or are incompetent. It’s that you’ve been given 125 projects to do, and you can’t do them all at the same time (see Rule #1). Each project expands the completion time for each of the other projects.
Consider this example analyzed by the management consultants of Focused Performance. You have three projects to complete – project A, project B, and project C. Each project takes four time units to complete. (A time unit can be hours, days, weeks – it doesn’t matter for the analysis).
If you did the projects one at a time, your time would be spent as follows:
AAAABBBBCCCC
This means you would have finished project A after four time units, finished project B after 8 time units, and finished project C after 12 time units.
If, instead, you multitask, you will spend your time bouncing back from project to project. Your time spent might be something like:
AABBCCABCABC
Under this scenario, it would take you 10 time units to finish project A (vs. 4), and 11 time units to finish project B (vs. 8). Both projects A and B would be better off without multitasking.
This analysis doesn’t even take into consideration any loss in efficiency or accuracy caused by shifting focus from A to B to C and back again (see Rule #3).
Nor does it take into consideration what happens in the real world. That is, while you are working on A or B or C, you are required to start D, E, and F.
Rule #3: Shifting mental focus from task to task costs time!
In the example from Rule #2, multitasking did not have an impact upon the completion of project C. It required 12 time units to complete, whether by multitasking or singletasking (is there such a word?).
The fact is that it would take longer to complete project C with multitasking. This is because it takes time for the brain to shift focus from task to task. The more time that is devoted to a single task, the less time is lost in the shift.
An American Psychological Association published study (Executive Control of Cognitive Processes in Task Switching) noted the hidden costs of multitasking. We all exercise these “executive control” processes, within our brain’s prefrontal cortex and other neural regions. With these cognitive processes, we establish priorities among tasks and allocate the mind’s resources to them. We need specific mental resources to perceive, think, and act, and all of these are supervised through executive control.
The study had subjects switch between tasks, such as solving math problems or classifying geometric objects. The researchers measured the speed of performance. The results?
For all types of tasks, the subjects lost time when they had to switch from one task to another. And, the time costs increased with the complexity of the tasks, and with the unfamiliarity of the tasks.
The researchers believe that two distinct stages are involved in executive control of task shifting. One is “goal shifting” – “I want to do this now instead of that”. The other is “rule activation” – “I’m turning off the rules for that and turning on the rules for this”. Both stages are required in the shift from task to task.
Rule #4: Multitasking reduces your level of comprehension!
If you are still reading this piece, it means that you were probably multitasking when you read the first two paragraphs. If you were singletasking at the time, you would have learned that we are only presenting three rules of multitasking, not four, and you would have stopped reading by now.
Note: The original piece in Wolverine Café had some additional links to the various studies, but I could not find them when I reposted this in 2019.