Dan Stern describes “vitality affects” as effervescent, variable characteristics of feeling that separate active from immobile. These feeling states are induced by temporary shifts in essential life processes - motivation, appetite, and tension. Vitality affects are different from discrete categorical affects in that the former can be experienced not only during the performing of a categorical signal but also in an action that has no intrinsic categorical affect signal. Stated differently, vitality affects are patterned changes in affect occurring over time, while categorical affects are driven by distinct levels of activation and arousal. These fundamental differences underlie Stern’s argument that mother-child attunement must occur primarily through vitality affects; since attunement appears to be a fluid process, it must be associated with dynamic, not discrete, categorical affect surges.
In defining vitality affects Stern also gives examples of their connection to the performance of any behavior and their relationship with three fundamental modalities of perception: intensity, time, and shape. For instance, whether or long or short, rhythm can be presented or identified through seeing, listening, smelling, touching, or tasting. According to Stern, the omnipresent existence of vitality affects in behavior regardless of the type of perception makes them essential for inclusion in affect categories that describe caregiver’s subjective inner states during acts of attunement.
Finally, vitality affects demonstrate how attunement is an ongoing, often unconscious process; this is critical. If attunement is unconscious, the capacity for one person to “be with” another can transcend behavioral imitation, verbal reinforcement, “mirroring”, and the common understanding of empathy (all largely conscious occurrences). Thus, Stern’s argument for vitality affects not only describes mother-child attunement but lends understanding for the interconnectedness of human beings.