When I use my left eye to center on someone else's left eye I find myself mimicking the expressions almost below the level of my conscious control. It feels as if I am developing a new independent usage of my left facial muscles as an effect of the mimicking. It is not at a level at which the right side is able to express but something very new for me. There seems to be a connection between empathy and muscle mimicking. My sense is my left eye/ face has been underdeveloped as I would exclusively focus on the right side of the face of others.
Empathy of either sort relies on unconscious mimicry: “empathic individuals exhibit nonconscious mimicry of the postures, mannerisms, and facial expressions of others (the ) to a greater extent than nonempathic individuals” (Carr et al., 2003). The ability to mimic is key to the empathic process of relaying information from one brain area to another via “mirror neurons”:
That finding is evidence that unintentional speech imitation extends to lipreading, even for normal hearing individuals with no formal lipreading experience, they wrote in a paper titled "Alignment to Visual Speech Information."