My sister, tested as ISFP, has always been considered wild and outgoing, while I have always been regarded as calm and reasonable. The last time we met with our mother (ESFJ), she talked for an hour with little pause, interrupted only by questions and additions from our mother and by very few remarks from me. In that scene, ISFP clearly seemed the most social of the three types present (ISFP > ESFJ > INTJ). I would say that with people she knows my sister is a very social person; with people she does not know, however, she is often almost shy.
So the thing to consider when attempting to answer the question of this thread is the social context. Is there a neutral context?