Scientists seem to agree that humans are not really able to multi-task. Checking your phone messages while driving, or replying to every email the second they pop up is not very healthy.
This got me thinking. The stereo types are as follows: the extravert manager proudly claims that the above rule is incorrect, she can easily maintain dozens of email, phone, and live conversations in parallel. The introvert coder thinks the above is absolutely true, the buzzing of the microwave in the background kills her concentration.
I think the manager is actually not multi-tasking that much, and the coder might do a bit of it. If you are a manager, your task is to juggle lots of people and keep everything moving. I would consider this as one task.
If you are coding, you might find yourself rewriting 10 different modules, updating a database, fixing the front end, all in one, all components are open in the editor and the system won’t work unless you fixed all of them. That’s a bit more than one task.
So, I think it all depends on what you all a task.