I'm looking for quantifiable results from studies; not best guesses please.
I quite frequently find that after an interruption I need to gather my thoughts and refocus on the task I was performing when I was interrupted. The time seems to vary depending on the complexity of the task and how long I've been interrupted for, and sometimes even how worthwhile I perceived the interruption to be.
For example, a pointless interruption costs me more in recovery time than a worthwhile interruption that I can mentally dismiss more easily. I'd very much like to know if there has been any research in this area and what the results show.