In a comment, Adam Khan, author of Self-Help Stuff that Works and the MoodRaiser blog, pointed me to the work of John Gottman, a University of Washington psychologist who studies how couples interact.
As a psychologist, Gottman studies behavior, not neurochemistry or brain function. But he has an interesting concept called "bidding for connection." His idea is, we constantly make attempts to connect with others via words, looks, actions, etc. In a good relationship, our bids are answered regularly.
You could look at Gottman's bids as attempts to enter into oxytocin-producing exchanges.
At any rate, on the Gottman Institute website are several fun quizzes, including a quiz that helps you understand the way you tend to bid for connection.