You may be interested in Raymonde Carroll's Cultural Misunderstandings, which is about differences in French vs American cultures and how these manifest in everyday affairs. Much of the second chapter ("Conversation") is devoted to puzzling out the differences between what you call the interrupt culture, and Carroll classifies as the norm for French conversation, vs the wait culture, which for her is the norm for American conversation.

A few quotations (there's much more on this in the book):

a party, in a university town in the United States, in honor of a well-known French academic. The host and most of the guests are French. There are a few scattered Americans. The French academic, who has just been introduced to an American historian, looks interested. “I’m very interested in history . . . Are you familiar with Z (famous American historian)?” “Yes.” “What do you think of his latest book?” The American responds, talking about what he thinks of the book in question. The Frenchman, having stopped listening at a certain point, is glancing around the living room, and he eagerly widens the circle when another Frenchman approaches and “brutally interrupts” the conversation with a joke. The newcomer turns to the American, “What are you working on right now?” The latter, who has learned his lesson, responds briefly with “Oh, the same thing” and makes a joke. This little scene was described to me by the American in question, who added, “I really don’t understand French people; they only pretend to ask questions. This behavior especially surprised me coming, as it did, from such a famous man. He had no need to ask the question if he wasn’t interested in the answer. Of course I wasn’t going to fall into the same trap twice, so I joked ‘French-style’ instead of answering.” Americans often expressed surprise in my presence at the fact that French people, “who claim to be very big on manners,” are themselves so “rude”: “they interrupt you all the time in conversation,” “they finish your sentences for you,” “they ask you questions and never listen to the answer,” and so on. French people, on the other hand, often complain that American conversations are “boring,” that Americans respond to the slightest question with a “lecture,” that they “go all the way back to Adam and Eve,” and that they “know nothing about the art of conversation.”

[...]Let’s see what happens in a simple conversation between two French people. I (the speaker) look at my interlocutor, watch for signs of boredom or inattention. If the other person’s gaze begins to stray, to wander, I change my behavior, my tactic, or the subject, or else I cut myself short to allow him or her to speak. Of course, we are not talking about what truly happens in most cases but of the norm, the “ideal” situation which remains unchanged, no matter how often the rule is broken. In the inverse case (someone is speaking to me), I have several means at my disposal to intervene or to indicate that I want to speak: facial expressions, lips which open as if to say something but remain silent, slight body movements, or gestures. If this does not obtain the desired result and I still am unable to speak, I must make use of other signs—a barely audible inhalation which indicates that I am going to speak, a discreet sigh, a chopped-off word—or the stratagems of last resort—“speaking of which” “funny you should mention that”—which in general have nothing to do with the preceding conversation but rather indicate that I would like to say something too. If I start to look distracted or take on a vacant stare, it is to indicate, in what is still an acceptable manner, that I am ready to abandon the conversation since there is no place in it for me. If this has no effect, my only hope lies in the intervention of a third party (a friend met fortuitously on the street, a host or hostess, a guest, or a table companion at a meal or party) to save me from this “pain in the neck.” If worse comes to worst, I can avail myself of the excuses that have the disadvantage of being obvious: a telephone call to make, something urgent to tell someone else that I almost forgot, and the like. When I am pushed to this extreme, I am really resentful at the other for having “cornered” me, for having “kept me” (and therefore held me against my wishes), for having “monopolized the conversation” for “hours”—in short, for not having “given” me a chance to speak, that is, for having refused me all meaningful presence.

[...]American conversation is closer to a hike with two or more people in unknown territory than to a game on familiar territory—hence the need immediately to situate the participants (the territory) and the importance of cooperation. Each person will contribute to the exploration according to his or her knowledge and capacities. We may return from this hike with our hands empty or full, depending on the moment, the mood, and the quality of each person’s contribution. Consequently, if I (an American) am unsure of my information, I do not pretend to know but let whoever might know more speak. But if I have something to “contribute,” I can speak as long as seems necessary to respond to a question, to share my information. And I will listen to the other in the same way when it is his or her turn, no matter what the other’s style may be. And since when I am finished, I will spontaneously stop speaking, the other person will wait for this silence, different from that of a thoughtful pause, to speak in turn. Any other kind of behavior would look like an insulting interruption to me; I would interpret it as a sign of lack of interest or, even worse, as frivolous and annoying, as contributing nothing more than “noise,” “senseless commotion,” or signs of “impatience” to the conversation. In short, the interruption is more a commentary on the person who interrupts than on the person who is interrupted. We can now understand why Americans are shocked by the “rudeness” of French people who “interrupt you all the time.”