

We have two distinct brain networks whose activity is mutually exclusive: the default mode network and the frontoparietal (AKA central executive or task positive) network. The DMN handles social interactions (among other things), while the FPN handles complex problem-solving—so if you’re engaged in what your brain thinks is a social interaction, it activates the DMN and deactivates the FPN.
Two likely possibilities:
Or perhaps they’ve learned the skill in such a way that the DMN can do it without the FPN—like if they treat it as a form of storytelling.