I don't really see Mayer as an introvert (or ISFP). Doesn't really interview like an ISFP below either. I don't know much about him really, but that quiet, sensitive image he put off seemed really contrived... an act or a stage he went through, I think.
Yeah, I watched that. He didn't turn in or pause at all. The interviews I have seen with clear cut isfp there was always pausing. Watch Eddie Vedder, he pauses quite a bit. Mayer seems uncomfortable with pauses in that video.