The Limbic Brain: Lewis, Amini and Lannon believe there are even more profound processes operating in our fourth quadrant – processes that reside not in our highly-evolved cerebral cortex, but in our more primitive limbic system (located in our mid-brain). The limbic brain serves four important functions that relate directly to the nature and dynamics of our interpersonal relationships. First, the limbic brain establishes our mood. This, in turn, sets the table for the quality (and outcomes) of our interpersonal relationships. Mood is a general tone that is influenced by events and internal physiological operations which may be far removed from the specific relationship in which we are participating. Yet, mood is a critical part of relationship and is generally an unconscious component of Quad Four.
Second, the limbic brain monitors both our internal bodily environment and the internal state of other organisms (particularly other people). The way in which we feel about another person is strongly influenced by such factors as our blood pressure, heart rate, digestive processes, and even the temperature of our body. All of this is monitored by the limbic brain, which in turn offers Quad Four interpretations of what these physiological processes mean in terms of our relationship with this other person. While these processes may be primarily influenced by other environmental conditions and by our current mood, we tend to look to our immediate relationships when identifying the “cause” of how we feel. We also interpret how the other person is feeling about us—this is a capacity called “limbic resonance.” We are taught how to do this delicate monitoring during our childhood and primarily in relationship with people who parent us. Without this resonance, we are lost. Lewis, Amani and Lannon suggest that there are severe consequences when we lack resonance. We either become superficial in our relationships with other people (looking for external clues, having few internal cues) or grow indifferent to the welfare of other people (experiencing no resonance—or empathy—regarding anyone else.)
A third function of the limbic brain concerns nonverbal communication. Our limbic brain produces our facial expressions and other nonverbal expressions that we can’t directly control (Quad One: External). These nonverbal expressions, in turn, influence how other people see us (Quad Two) and how they chose to interact with us – thus, further reinforcing the interpersonal templates that we hold in our implicit memory.
A fourth function is perhaps of greatest importance in terms of the quality of interpersonal relationships which we find and create during our lives. Lewis, Amini and Lannon suggest that the limbic brain produces our capacity (and strong desire) to attach to other people. They note that we are attracted to specific people in part because our limbic brain releases certain opiates when we are in the physical presence of these people. Even more broadly, a baby learns what love feels like through his attachment to a mothering figure and through the intricate and reciprocal interplay of emotional states, and physical connectedness (touching, viewing, seeing, smelling) between parent and child. Through this interplay, the child learns not only what loves feels like, but also how to establish a loving relationship. This interpersonal learning (stored in Quad Four) may be appropriate or it may be terribly flawed.1K Club