In job postings I often see the requirement "must be able to multitask". I often wonder if the people who write these job postings have ever held jobs that required intense concentration over time in order to understand and then master hard problems.
In both research and many software development efforts I have found the overhead associated with a context switch to be large. Today I read the following paragraph from a 2010 article that I think nails it.
The nature of the job. The mental stage that psychologists define as "flow" is one of sustained concentration on the task at hand and a pure focus on your attention on a project. In other words, it's the ability to work without interruption on a task until you've found a natural stopping point. A lot of developers strive for flow when they're working, which is why one meeting can blow an entire day's worth of work. It takes time to get in and out of flow and to retrace your steps to the point where you can move forward.
If you are hiring for a position that only needs shallow thinking, go ahead and keep that "must be able to multitask" requirement. But if you are hiring for a position that requires deep thinking on hard problems, you should consider dropping it.