A well known effect of multitasking is that if you have to switch to do another one, then your performance of both will decrease, in compared to the performance when you do them separately.
However, in my experience, it seems to me that the headache in the prefrontal cortex made by the interruption is lesser when the person doing the multitask receive necessary information via another person, not by looking up by themselves.
For example, I imagine an experiment in which when the participants are focusing to do task A, then they are interrupted and need to do task B. In order to do task B, they need to find a necessary piece of information. Group 1 of participants have to find it by themselves (e.g. google it). Group 2 can find it by asking a staff. Let the number of questions need to be asked, and the time to gather information be the same in both groups. After finishing task B they need to return to task A to finish. Which group has better performance in both task?
Is there any source about this? I search in Google Scholar with the query
multitasking social interaction performance, but the results mostly about interruption during social interaction, or interruption via social media.