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July 10, 2012


george storm

The case is at best overstated.

Our multi-tasking capability is undoubtedly limited, and the practical complexity depends on the mix of tasks.
But many "single tasks" that we train ourselves to do are multitasking. Reading aloud comprises several different tasks, as does sight-reading when playing a string instrument (included in doing the latter half-way-decently is automation of eye-to-expected-sound at the same time as eye-to-hand, otherwise sight-reading goes terribly out of tune). Then there are plenty of musicians (choir-masters and repetiteurs) who can sight-read multiple lines on a piano while singing yet another line; you can argue that this is actually multiplexing part of the function, but if it is pure multiplexing we would expect the available speed for each of the tasks to be degraded proportionally to the number of tasks - and there's no evidence for this.

However, I would agree that the most successful multitasking uses different systems within our brains to perform the different tasks. It is likely that the task of listening to multiple conversations simultaneously is achieved via multiplexing, but listening while driving is almost certainly true multitasking (parallel processing - more on this later).
BTW, the reason that new drivers find conversations while driving much more difficult than experienced ones is that much of the training for driving is via the auditory system - and new drivers still using this training method.

On the other hand, I would agree that follwing a map (or any other visual task) while driving is a multiplex function that inevitably detracts from driving capability. On the other hand, the amount of information we need to extract from a satav should be small...
In complete contrast... Such evidence as exists (Helen Beh 1999) appears to show that listening to music at low-to-moderate levels while driving actually improves all aspects of driving performance.
Unsurprisingly, listening to music degrades performance in any task with aditory content - and this includes silent reading (Dalton 2007).


The optical illusion is a great example of how two people can see the same thing and describe it with completely opposite descriptions.

"The cubes have green tops"
"No, they have green bottoms"

The fact that a person cannot simultaneously see the green as top and bottom is far from a disadvantage, it's simply being rational.

A similar arguements to what you are proposing are:

You cannot simulaneously speak English and Spanish, therefore you cannot multitask.
You cannot be in Washington D.C. and Brazil at the same time, therefore you cannot multitask.

A person "sees" a green top or bottom based on the brain trying to make sense out of visual information, once you attribute directionality to it.... the brain fills in the gaps with if **** then ****, otherwise we would have none of these clever optical illusions.

Don Humphrey

Tell me how my Mother could talk on the phone while
preparing supper.

John Dunn

By alternation. My mom did the same thing. Occasionally, there'd be a small mishap, noting lethal of course, but something would maybe boil over.

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